This is the
talk page for discussing improvements to the
Climate change article. This is not a forum for general discussion of the article's subject. |
Article policies
|
Find sources: Google ( books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL |
This page is not a forum for general discussion about Climate change. Any such comments may be removed or refactored. Please limit discussion to improvement of this article. You may wish to ask factual questions about Climate change at the Reference desk. |
Frequently asked questions To view an answer, click the [show] link to the right of the question. To view references used by an answer, you must also click the [show] for references at the bottom of the FAQ. Q1: Is there really a scientific consensus on climate change?
A1: Yes. The
IPCC findings of recent warming as a result of human influence are explicitly
recognized as the "consensus" scientific view by the science academies of all the major industrialized countries. No scientific body of national or international standing presently rejects the basic findings of human influence on recent climate. This
scientific consensus is supported by over 99% of publishing climate scientists.
[1]
Q2: How can we say climate change is real when it's been so cold in such-and-such a place?
A2: This is why it is termed "global warming", not "(such-and-such a place) warming". Even then, what rises is the average temperature over time – that is, the temperature will fluctuate up and down within the overall rising trend. To give an idea of the relevant time scales, the standard averaging period specified by the World Meteorological Organisation (WMO) is 30 years. Accordingly, the WMO defines climate change as "a statistically significant variation in either the mean state of the climate or in its variability, persisting for an extended period (typically decades or longer)."
[2] Q3: Can't the increase of CO2 be from natural sources, like volcanoes or the oceans?
A3: While these claims are popular among global warming skeptics,
[3]
[4] including academically trained ones,
[5]
[6] they are incorrect. This is known from any of several perspectives:
Q4: I think the article is missing some things, or has some things wrong. Can I change it?
A4: Yes. Keep in mind that your points need to be based on documented evidence from the peer-reviewed literature, or other information that meets standards of
verifiability,
reliability, and
no original research. If you do not have such evidence, more experienced editors may be able to help you find it (or confirm that such evidence does not exist). You are welcome to make such queries on the article's talk page but please keep in mind that the talk page is for discussing improvements to the article, not discussing the topic. There are many forums that welcome general discussions of global warming, but the article talk page is not such a forum. Q5: Why haven't the graphs been updated?
A5: Two reasons:
Q6: Isn't climate change "just a theory"?
A6: People who say this are abusing the word "theory" by
conflating its common meaning with its scientific meaning.
In common usage, "theory" can mean a hunch or guess, but a
scientific theory, roughly speaking, means a coherent set of explanations that is compatible with observations and that allows predictions to be made. That the temperature is rising is an observation. An explanation for this (also known as a
hypothesis) is that the warming is primarily driven by greenhouse gases (such as CO2 and methane) released into the atmosphere by human activity.
Scientific models have been built that predict the rise in temperature and these predictions have matched observations. When scientists gain confidence in a hypothesis because it matches observation and has survived intense scrutiny, the hypothesis may be called a "theory". Strictly speaking, scientific theories are never proven, but the degree of confidence in a theory can be discussed. The scientific models now suggest that it is "extremely likely" (>95%) to "virtually certain" (>99%) that the increases in temperature have been caused by human activity as discussed in the
IPCC Fifth Assessment Report. Global warming via greenhouse gases by human activity is a theory (in the scientific sense), but it is most definitely not just a hunch or guess. Q7: Does methane cause more warming than CO2?
A7: It's true that methane is more potent molecule for molecule. But there's far less of it in the atmosphere, so the total effect is smaller. The atmospheric lifetime of methane (about 10 years) is a lot shorter than that of CO2 (hundreds to thousands of years), so when methane emissions are reduced the concentration in the atmosphere soon falls, whereas CO2 accumulates in the atmosphere over long periods. For details see the
greenhouse gas and
global warming potential articles.
Q8: How can you say there's a consensus when lists of "skeptical scientists" have been compiled?
A8: Consensus is not the same as unanimity, the latter of which is impractical for large groups. Over 99% of publishing climate scientists agree on anthropogenic climate change.
[1] This is an extremely high percentage well past any reasonable threshold for consensus. Any list of "skeptical scientists" would be dwarfed by a comparably compiled list of scientists accepting anthropogenic climate change. Q9: Did climate change end in 1998?
A9: One of the strongest
El Niño events in the instrumental record occurred during late 1997 through 1998, causing a spike in global temperature for 1998. Through the mid-late 2000s this abnormally warm year could be chosen as the starting point for comparisons with later years in order to produce a cooling trend; choosing any other year in the 20th century produced a warming trend. This no longer holds since the mean global temperatures in 2005, 2010, 2014, 2015 and 2016 have all been warmer than 1998.
[12]
More importantly, scientists do not define a "trend" by looking at the difference between two given years. Instead they use methods such as
linear regression that take into account all the values in a series of data. The
World Meteorological Organisation specifies 30 years as the standard averaging period for climate statistics so that year-to-year fluctuations are averaged out;
[2] thus, 10 years isn't long enough to detect a climate trend. Q10: Wasn't Greenland much warmer during the period of Norse settlement?
A10: Some people assume this because of the island's name. In fact the
Saga of Erik the Red tells us Erik named the new colony Greenland because "men will desire much the more to go there if the land has a good name."
[13] Advertising hype was alive and well in 985 AD.
While much of Greenland was and remains under a large ice sheet, the areas of Greenland that were settled by the Norse were coastal areas with fjords that, to this day, remain quite green. You can see the following images for reference:
Q11: Are the IPCC reports prepared by biased UN scientists?
A11: The
IPCC reports are not produced by "UN scientists". The IPCC does not employ the scientists who generate the reports, and it has no control over them. The scientists are internationally recognized experts, most with a long history of successful research in the field. They are employed by various organizations including scientific research institutes, agencies like
NASA and
NOAA, and universities. They receive no extra pay for their participation in the IPCC process, which is considered a normal part of their academic duties. Q12: Hasn't global sea ice increased over the last 30 years?
A12: Measurements show that it has not.
[14] Claims that global sea ice amounts have stayed the same or increased are a result of
cherry picking two data points to compare, while ignoring the real (
strongly statistically significant) downward trend in measurements of global sea ice amounts.
Arctic sea ice cover is declining strongly; Antarctic sea ice cover has had some much smaller increases, though it may or may not be thinning, and the Southern Ocean is warming. The net global ice-cover trend is clearly downwards. Q13: Weren't scientists telling us in the 1970s that the Earth was cooling instead of warming?
A13: They weren't – see the article on
global cooling. An article in the
Bulletin of the American Meteorological Society has reviewed the scientific literature at that time and found that even during the 1970s the prevailing scientific concern was over warming.
[15] The common misperception that cooling was the main concern during the 1970s arose from a few studies that were sensationalized in the popular press, such as a short nine-paragraph article that appeared in Newsweek in 1975.
[16] (
Newsweek eventually apologized for having misrepresented the state of the science in the 1970s.)
[17] The author of that article has repudiated the idea that it should be used to deny global warming.
[18] Q14: Doesn't water vapour cause 98% of the greenhouse effect?
A14: Water vapour is indeed a major greenhouse gas, contributing about 36% to 70% (not 98%) of the total greenhouse effect. But water vapour has a very short atmospheric lifetime (about 10 days), compared with decades to centuries for greenhouse gases like CO2 or nitrous oxide. As a result it is very nearly in a
dynamic equilibrium in the atmosphere, which globally maintains a nearly constant
relative humidity. In simpler terms, any excess water vapour is removed by rainfall, and any deficit of water vapour is replenished by evaporation from the Earth's surface, which literally has oceans of water. Thus water vapour cannot act as a driver of climate change.
Rising temperatures caused by the long-lived greenhouse gases will however allow the atmosphere to hold more vapour. This will lead to an increase in the absolute amount of water vapour in the atmosphere. Since water vapour is itself a greenhouse gas, this is an example of a positive feedback. Thus, whereas water vapour is not a driver of climate change, it amplifies existing trends. Q15: Is the fact that other solar system bodies are warming evidence for a common cause (i.e. the sun)?
A15: While some solar system bodies show evidence of local or global climate change, there is no evidence for a common cause of warming.
Q16: Do scientists support climate change just to get more money?
A16: No,
Q17: Doesn't the climate vary even without human activity?
A17: It does, but the fact that natural variation occurs does not mean that human-induced change cannot also occur. Climate scientists have extensively studied natural causes of climate change (such as orbital changes, volcanism, and solar variation) and have ruled them out as an explanation for the current temperature increase. Human activity is the cause at the 95 to 99 percent confidence level (see the
IPCC Fifth Assessment Report for details). The high level of certainty in this is important to keep in mind to spot mention of natural variation functioning as a
distraction. Q18: Should we include the view that climate change will lead to planetary doom or catastrophe?
A18: This page is about the science of climate change. It doesn't talk about planetary doom or catastrophe. For a technical explanation, see
catastrophic climate change, and for
paleoclimatic examples see
PETM and
great dying. Q19: Is an increase in global temperature of, say, 3 degrees Celsius (5.4 degrees Fahrenheit) important?
A19: Though it may not sound like much, a global temperature rise of 3 degrees Celsius (5.4 degrees Fahrenheit) is huge in climate terms. For example, the sea level rise it would produce would flood coastal cities around the world, which include most large cities.
Q20: Why are certain proposals to change the article discarded, deleted, or ignored? Who is/was
Scibaby?
A20:
Scibaby is/was a
long term abusive
sock-master (or coordinated group of sock masters) who has created
1,027 confirmed sock puppets, another
167 suspected socks, and probably many untagged or unrecognized ones.
This page lists some recent creations. His modus operandi has changed over time, but includes proposing reasonably worded additions on the talk page that only on close examination turn out to be irrelevant, misinterpreted, or give
undue weight to certain aspects. Scibaby is banned, and Scibaby socks are blocked as soon as they are identified. Some editors silently revert his additions, per
WP:DENY, while others still assume good faith even for likely socks and engage them. Q21: What about this really interesting recent peer-reviewed paper I read or read about, that says...?
A21: There are hundreds of peer-reviewed papers published every month in
respected scientific journals such as
Geophysical Research Letters, the
Journal of Climate, and others. We can't include all of them, but the article does include references to individual papers where there is consensus that they best represent the state of the relevant science. This is in accordance with the "due weight" principle (
WP:WEIGHT) of the
Neutral point of view policy and the "Wikipedia is not an indiscriminate collection of information" principle (
WP:IINFO) of the
What Wikipedia is not policy. Q22: Why does the article define "climate change" as a recent phenomenon? Hasn't the planet warmed and cooled before?
A22: Yes, the planet has warmed and cooled before. However, the term "climate change" without further qualification is widely understood to refer to the recent episode and often explicitly connected with the greenhouse effect. Per
WP:COMMONNAME, we use the term in this most common meaning. The article
Climate variability and change deals with the more general concept. Q23: Did the CERN
CLOUD experiment prove that climate change is caused not by human activity but by cosmic rays?
A23: No. For cosmic rays to be causing global warming, all of the following would have to be true, whereas only the italicized one was tested in the 2011 experiment:
[28]
Q24: I read that something can't fix climate change. Is this true?
A24: Yes, this is true for all plausible single things including: "electric cars", "planting trees", "low-carbon technology", "renewable energy", "Australia", "capitalism", "the doom & gloom approach", "a Ph.D. in thermodynamics". Note that it is problematic to use the word "fix" regarding climate change, as returning the climate to its pre-industrial state currently appears to be feasible only over a timeframe of thousands of years. Current efforts are instead aimed at mitigating (meaning limiting) climate change. Mitigation is strived for through the combination of many different things. See
Climate change mitigation for details. References
|
This article is written in British English, which has its own spelling conventions (colour, travelled, centre, defence, artefact, analyse) and some terms that are used in it may be different or absent from other varieties of English. According to the relevant style guide, this should not be changed without broad consensus. |
Climate change is a featured article; it (or a previous version of it) has been identified as one of the best articles produced by the Wikipedia community. Even so, if you can update or improve it, please do so. | ||||||||||||||||||||||||||||
This article appeared on Wikipedia's Main Page as Today's featured article on June 21, 2006, and on October 31, 2021. | ||||||||||||||||||||||||||||
|
This
level-3 vital article is rated FA-class on Wikipedia's
content assessment scale. It is of interest to multiple WikiProjects. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
This article has been
mentioned by multiple media organizations:
|
The
contentious topics procedure applies to this page. This page is related to
climate change, which has been
designated as a contentious topic. Editors who repeatedly or seriously fail to adhere to the purpose of Wikipedia, any expected standards of behaviour, or any normal editorial process may be blocked or restricted by an administrator. Editors are advised to familiarise themselves with the contentious topics procedures before editing this page. |
Other talk page banners | |||||||||||||
|
On 3 August 2020, it was proposed that this article be moved from Global warming to Climate change. The result of the discussion was moved. |
|
Index
1,
2,
3,
4,
5,
6,
7,
8,
9,
10 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 41, 42, 43, 44, 45, 46, 47, 48, 49, 50 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 61, 62, 63, 64, 65, 66, 67, 68, 69, 70 71, 72, 73, 74, 75, 76, 77, 78, 79, 80 81, 82, 83, 84, 85, 86, 87, 88, 89, 90 91, 92, 93, 94, 95 |
This page has archives. Sections may be automatically archived by Lowercase sigmabot III when more than 8 sections are present. |
Which of the following sections should be used in the Food and health section?
Robert McClenon ( talk) 04:47, 17 April 2024 (UTC) RfC restarted Bogazicili ( talk) 17:24, 18 May 2024 (UTC)
A.
Human health
The World Health Organization (WHO) calls climate change the greatest threat to global health in the 21st century. [1] Over 100 scientists writing in The Lancet have warned about the irreversible harms it poses. [2] According to the World Economic Forum, the most likely future scenario is of 14.5 million deaths caused by climate change by 2050. [3] Of those, 8.5 million deaths are associated with flooding, mostly because flooded areas expand the range of malaria. By 2050, the range of vector-borne diseases may expand to reach 500 million more people. Saltwater intrusion caused by sea level rise will also add over 800,000 cases of hypertension in coastal areas. [4]
Under the same scenario, around 1.6 million people will die in heatwaves by 2050, primarily those aged 65 and older, and 300,000 more will be killed by wildfires. [5] 30% of the global population currently live in areas where extreme heat and humidity are already associated with excess deaths. [6] By 2100, 50% to 75% of the global population would live in such areas. [7] p. 988 These and other climate change impacts are also expected to substantially increase the burden of stress-related mental health conditions. [8] The overall healthcare costs from climate change impacts would exceed 1$ trillion by 2050. [9] If the emissions continue to increase for the rest of century, then over 9 million climate-related deaths would occur annually by 2100. p.63
Food supply
Climate change has strong impacts on agriculture in the low latitudes, where it threatens both staple crops and important cash crops like cocoa and coffee. p.788 Agriculture will experience yield gains at high latitudes, but will also become more vulnerable to pests and pathogens. p.794 Extreme weather events adversely affect both food and water security, and climate change increases their frequency. p.9 Food prices spike after climate shocks. p.794 An increase in drought in certain regions could cause 3.2 million deaths from malnutrition by 2050, primarily in children under five. Many more children would grow up stunted as the result. [10] Under higher warming, global livestock headcounts could decline by 7-10% by 2050, as less animal feed will be available. p.748 Marine animal biomass decreases by 5% with every degree of warming, reducing fishery yields. p.718
In isolation, climate change is expected to increase the risk of hunger for 8 to 80 million people by 2050. p.725 However, total crop yields have been increasing since the middle of the 20th century due to agricultural improvements, and in spite of climate change. [11] p.832 By 2050, the overall number of people suffering from undernourishment and the associated health conditions is likely to decrease by tens to hundreds of millions. [12] Food security only worsens by 2050 in some combinations of severe climate change and low socioeconomic development, [13] but if the emissions remain high, it will likely decrease after 2050. This would be due to diminishing fisheries and livestock counts, and due to more frequent and severe crop failures. p.797
B.
The World Health Organization calls climate change the greatest threat to global health in the 21st century. [14] Over 100 scientists writing in The Lancet have warned about the irreversible harms it poses. [15] Extreme weather events affect public health, and food and water security. [16] [17] p. 9 Temperature extremes lead to increased illness and death. [18] [19] Climate change increases the intensity and frequency of extreme weather events. [20] p.9 It can affect transmission of infectious diseases. [21] [22] According to the World Economic Forum, 14.5 million more deaths are expected due to climate change by 2050. [23] 30% of the global population currently live in areas where extreme heat and humidity are already associated with excess deaths. [24] By 2100, 50% to 75% of the global population would live in such areas. [25] p. 988
While total crop yields have been increasing in the past 50 years due to agricultural improvements, climate change has already slowed the rate of yield growth. p. 9 Fisheries have been negatively affected in multiple regions. p. 9 Agricultural productivity was negatively affected in mid- and low-latitude areas, while some high latitude areas were positively affected. p.9 An increase in drought in certain regions could cause 3.2 million deaths from malnutrition by 2050 and stunting in children. [26] With 2C warming, global livestock headcounts could decline by 7-10% by 2050, as less animal feed will be available. p.748 If the emissions continue to increase for the rest of century, then over 9 million climate-related deaths would occur annually by 2100. p.63
C. Something else - Please provide a complete section.
Please enter A, B, or C (with the text) in the Survey. Please do not respond to the statements of other editors in the Survey.
Climate change is the greatest threat to global health in the 21st century. [27]. [28] [29] [30] p. 9 [31] [32] Climate change increases the intensity and frequency of extreme weather events [33] p.9 leading to increased illness and death. [34] [35]
Currently
- 30% of the global population live in extreme heat and humidity associated with excess deaths. [36]
- Food prices spike after climate shocks. p.794
- Climate change has slowed the rate of yield growth. p. 9 [37] p.832 p.9 p.788
- Fisheries have been negatively affected in multiple regions. p. 9
2050, The most likely scenario
- 14.5 million deaths [38] by flooding and malaria [39], malnutrition by droughts, heatwaves, wildfires. [40]
- risk of hunger for 8 to 80 million people. p.725 Many children grow up stunted. [41] p.797 [42]
- Agriculture yield gains at high latitudes, but more vulnerable to pests and pathogens. p.794
- With 2C warming, global livestock headcounts declines by 7-10%, as less animal feed will be available. p.748
- Marine animal biomass decreases by 5% with every degree of warming, reducing fishery yields. p.718
2100, The most likely scenario
Uwappa ( talk) 09:03, 19 April 2024 (UTC)
Climate change is the greatest threat to global health in the 21st century. [45], posing irreversible harms. [46] Climate change increases the intensity and frequency of extreme weather events [47] p.9, affecting public health, and food and water security. [48] [49] p. 9 [50] [51] Temperature extremes lead to increased illness and death. [52] [53]
- Currently
- 30% of the global population live in areas where extreme heat and humidity are already associated with excess deaths. [54] While total crop yields have been increasing in the past 50 years due to agricultural improvements, climate change has already slowed the rate of yield growth. p. 9 p.9 Fisheries have been negatively affected in multiple regions. p. 9
- By 2050
- 14.5 million more deaths are expected. [55]. With 2C warming, global livestock headcounts could decline by 7-10%, as less animal feed will be available. p.748 An increase in drought in certain regions could cause 3.2 million deaths from malnutrition and stunting in children. [56]
- By 2100
- 50% to 75% of the global population would live in extreme heat. [57] p. 988 If the emissions continue to increase for the rest of century, then over 9 million climate-related deaths would occur annually. p.63
Uwappa ( talk) 12:03, 29 April 2024 (UTC)
@ Efbrazil: I understand your (and others') objections to option A based on length, but remember this discussion from the start of February, when many of us were looking to cut material from the "Causes" section, and you had yourself proposed removing 4-5 paragraphs? This option is still very much available: we simply couldn't do it at the time because Causes of climate change wasn't a live article yet, but it is done now. In fact, it often intentionally duplicates the current article, precisely to make it easier to cut from here. Thus, if we do in fact remove 4-5 paragraphs from causes but add 2 paragraphs here, on food and health, we will still ultimately have a shorter article.
I also think that every sentence in A provides unique and distinct information our readers would likely not know otherwise, but then again, I would think that as its author. I realize that all the editors who have so far voted for B may still want the section to be shorter rather than longer even after we condense "Causes". If so, which parts of A would you consider to be the most "skippable"? InformationToKnowledge ( talk) 17:25, 22 April 2024 (UTC)
InformationToKnowledge had also argued about removing Effects of climate change on human health as an articleI would like to clarify that my proposal was to merge that with the general Effects of climate change - following the logic that once we strip out the material from the article that appears to lack widespread support, such as the "people falling through thinner ice on frozen rivers" thing, there wouldn't be much left that would not be better covered in either that article, Climate change and infectious diseases or Psychological impact of climate change.
I'm opposed to giving more weight to human impacts than we are giving to nature and wildlife.Well, if that is your main objection, then once we remove 4-5 paragraphs from "Causes", that would leave us enough space to both have 4 paragraphs on food and health and to add 2-3 paragraphs to "Nature and wildlife". Considering the work I have done to date on articles such as Extinction risk from climate change or Effects of climate change on biomes (admittedly, more of a work in progress), it wouldn't be overly difficult for me to find reliably referenced material to complement the two paragraphs already present.
An expert elicitation concluded that the role of climate change in armed conflict has been small compared to factors such as socio-economic inequality and state capabilities.seem very awkward to say the least, and could be cut at least in part, if not fully. We have already argued over the limited reliability of this passage -
In some regions, the rise in temperature and humidity may be too severe for humans to adapt to. With worst-case climate change, models project that almost one-third of humanity might live in Sahara-like uninhabitable and extremely hot climates.as well. There is most likely room to condense a paragraph or two there - and then the entire section devoted to impact on humans would be of similar size to "Nature and wildlife" once that is expanded by several paragraphs - likely even after "Food and health" is expanded to four paragraphs, and certainly if it stays at two.
B I could live with, but would want 4 sentences cut that are redundant with other areas or are just generally alarmist rather than informative.Would it be those four sentences, by any chance?
Extreme weather events affect public health, and food and water security.[92][93]p. 9 Temperature extremes lead to increased illness and death.[94][95] Climate change increases the intensity and frequency of extreme weather events.[96]p.9 It can affect transmission of infectious diseases.
Proposal A gets too far into the weeds for me and causes that word count imbalance with the natural world.Well, it's been said already that expanding the natural world in parallel would be one way to address the latter objection. As for the former, that's not really useful feedback. Can you at least identify the sentences you take an issue with, similar to what you have done for B?
On balance, I think the existing text on page is not bad. It does a good job of raising various issues without making dubious claims.-Not really. As we have discussed exhaustively on this page in February and March, several sentences are likely to be fairly misleading for a typical reader. I.e.
Climate change is affecting food security. It has caused reduction in global yields of maize, wheat, and soybeans between 1981 and 2010.- The straightforward read of that paragraph is that the current/2010 yields of those crops are lower than they were in the 1980s - and it would be completely wrong, because the comparison is drawn with the counterfactual present where climate change was not happening, while a clear increase had occurred in the real world.
Up to an additional 183 million people worldwide, particularly those with lower incomes, are at risk of hunger as a consequence of these impacts.- This sentence does not even specify anything. Up to 183 million by when? By next year? In 10 years' time? By 2050? (the correct answer). By 2100? Once climate change passes 2 degrees? Once it is at 6 degrees? Is it the maximum possible impact on hunger? This sentence is so vague that all these readings are equally valid. And again, this finding is relative to a counterfactual 2050, which is not very useful to general readers, which is why A has those two detailed sentences covering the actual projections relative to the present instead.
Crop production will probably be negatively affected in low-latitude countries, while effects at northern latitudes may be positive or negative.- I am surprised you don't seem to consider this sentence "wishy-washy" or too detailed.
As for cuts from version B, the 4 sentences you point to are generally fluffy and could be be folded into other sentences.I am glad you agree on this, but Bogazicili has been fairly insistent on those specific phrasings, leading up to the DRN.
This isn't even specific to human health or agriculture. Too vague and unnecessary- Well, this phrasing comes from the title, which is The 2023 report of the Lancet Countdown on health and climate change: the imperative for a health-centred response in a world facing irreversible harms, and we both felt it was important to cite it here. I suppose we can rewrite this sentence with one or more findings from that report's summary graphic, but it might be best if you can specify which one you wouldn't oppose for one reason or another.
Almost all food scarcity is due to distribution issues, and "could" is wishy washy. Why not make a clear claim about agricultural output instead?- It is "could" to acknowledge that these projections are not set in stone (same point you were making earlier), and the number is for one scenario of several. However, A's final paragraph does discuss agricultural output. Would you prefer some variation of that wording?
Here we have something specific and probably valid, but not interesting given the context.Well, livestock is an important (even if technically skippable) part of the global food system, with a role comparable to fishing, so it makes no sense to mention one but not the other. Not to mention that an effective decimation is not tiny by any means. Literally the next sentence after that figure in the AR6 is:
Changes to African grassland productivity will have substantial, negative impacts on theI cite this in Effects of climate change on livestock, but thought that it is "not global enough" for this section. However, I suppose it can be rephrased as
With 2C warming, global livestock headcounts are likely to decline by 7-10% by 2050, affecting (can't think of a stronger word right now) the livelihoods of over 180 million people.
Why focus on a scenario where emissions continue increasing for the rest of the century, particularly as we don't say how much even,- I consider this a better phrasing than "high-emission scenario" or "worst-case climate change scenario" or the like. People could have vastly different ideas about what those mean, while this wording is immediately much clearer.
...and then attach a bs number to it? Nobody is predicting RCP 8.5 at this time.- So, you consider this alarmist? I actually view it the other way around. Too many people nowadays appear to believe that climate change would lead to billions dying, global collapse, etc. in the fairly near future. (See Climate change and civilizational collapse#Public opinion for the closest we have to objective evidence on the subject.) Thus, presenting this high-emission figure (again, from the AR6) as the "upper bound" for 2100 is actually likely to surprise a lot of people as "too low" - and those are the people who definitely need to see this, and are likely to scroll past the rest of the article and persist in their thinking otherwise. InformationToKnowledge ( talk) 20:16, 27 April 2024 (UTC)
By 2050, 14.5 million deaths are likely, including 8.5 million from flooding and waterborne [water-associated?], 3.2 million from malnutrition due to droughts, 1.6 million from heatwaves by 2050 and 300,000 from wildfires.And again, I would not want to skip over the rather important situation where the bulk of projections say food supply would improve by 2050. InformationToKnowledge ( talk) 19:57, 2 May 2024 (UTC)
Uwappa, would you mind striking down your earlier comment in the survey section above with <s></s>? It looks like you voted twice now. Or make a comment that you made an alternate suggestion? Bogazicili ( talk) 15:21, 3 May 2024 (UTC)
I would prefer the more concise B given we have {{ main article}} links for readers seeking more detail. However, I find that B does not convey the same meaning as A, or even the existing wording: B currently states "Agricultural productivity was negatively affected in mid- and low-latitude areas, while some high latitude areas were positively affected". This gives the impression that agriculture in the high latitudes may only be positively affected, which does not contain the nuance that A has ("Agriculture will experience yield gains at high latitudes, but will also become more vulnerable to pests and pathogens"); the existing wording ("effects at northern latitudes may be positive or negative") shows this duality better (though "northern" should be reworded to "higher"). ~ KN2731 { talk · contribs} 11:55, 6 May 2024 (UTC)
Respectfully, I have learned the most truth about climate and the current climate change from Ben Davidson's https://www.youtube.com/@Suspicious0bservers/featured and Thunderbolts Project https://www.youtube.com/@ThunderboltsProject/playlists
They make the whole picture fit together better than average information sources. With Respect Eva Zdrava 46.248.93.31 ( talk) 15:06, 21 April 2024 (UTC)
This article was the subject of a Wiki Education Foundation-supported course assignment, between 16 January 2024 and 11 May 2024. Further details are available on the course page. Student editor(s): Floralepe ( article contribs).
— Assignment last updated by LynSchwendy ( talk) 03:29, 14 May 2024 (UTC)
I don't know that the claim we make in the lead is correct. The IPCC source used to back the statement is blurring the issue of CO2 rise and temperature rise. The claim we make in the lead is exclusive to temperature.
The article on Bølling–Allerød warming appears to contradict the warming claim. Specifically, it says that at the end of the last ice age there was 3 C of warming in arctic waters within a period of 90 years. While global temperature records that far back are of course not as accurate, we do appear to know certain things, such as Meltwater pulse 1A causing sea level rise of 50 mm per year, which is over 10 times the current rate.
I don't know that we have enough information to uphold the claim we are making here in the lead. Most prehistoric temperature records do not have a resolution sufficient to make comparisons to modern times, and as recently as the last ice age there appear to be conflicting claims. Efbrazil ( talk) 00:08, 8 May 2024 (UTC)
Since 1970 the global average temperature has been rising at a rate of 1.7 °C per century, compared to a long-term decline over the past 7,000 years at a baseline rate of 0.01 °C per century (NOAA, 2016; Marcott et al., 2013). These global-level rates of human-driven change far exceed the rates of change driven by geophysical or biosphere forces that have altered the Earth System trajectory in the past (e.g., Summerhayes, 2015; Foster et al., 2017); even abrupt geophysical events do not approach current rates of human-driven change.
A.2 The scale of recent changes across the climate system as a whole and the present state of many aspects of the climate system are unprecedented over many centuries to many thousands of years.
{Cross-Chapter Box 2.1, 2.2, 2.3, 5.1} (Figure SPM.1)
A.2.1 In 2019, atmospheric CO2 concentrations were higher than at any time in at least 2 million years (high confidence), and concentrations of CH4 and N2O were higher than at any time in at least 800,000 years (very high confidence). Since 1750, increases in CO2 (47%) and CH4 (156%) concentrations far exceed, and increases in N2O (23%) are similar to, the natural multi-millennial changes between glacial and interglacial periods over at least the past 800,000 years (very high confidence).
{2.2, 5.1, TS.2.2}
A.2.2 Global surface temperature has increased faster since 1970 than in any other 50-year period over at least the last 2000 years (high confidence). Temperatures during the most recent decade (2011–2020) exceed those of the most recent multi-century warm period, around 6500 years ago13 [0.2°C to 1°C relative to 1850–1900] (medium confidence). Prior to that, the next most recent warm period was about 125,000 years ago when the multi-century temperature [0.5°C to 1.5°C relative to 1850–1900] overlaps the observations of the most recent decade (medium confidence).
{Cross-Chapter Box 2.1, 2.3, Cross-Section Box TS.1} (Figure SPM.1)
andis doing a lot of work there, as it's much easier to show GHG emissions are unprecedented. Still, I would be okay restoring that sentence, cited to SR15, and remove the lead sentence. —Femke 🐦 ( talk) 19:35, 8 May 2024 (UTC)
The article on Bølling–Allerød warming appears to contradict the warming claim. Specifically, it says that at the end of the last ice age there was 3 C of warming in arctic waters within a period of 90 years.- I thought you would know we should not cite our own articles - particularly not when they are C-level. Have you actually evaluated the claim? The reference cited does not appear to say anything of a kind, although half of it is paywalled.
Are there any sources about global average increase in Bølling–Allerød warming?I still cannot find an exact figure for now: what I did find, however, was an indication that the warming was limited to the Northern Hemisphere, while the Southern Hemisphere cooled. Figure c) on the lower-left appears to show this the best. There is also no other mention of a 90-year interval specifically: the closest might be in this reference:
The results obtained with three methods shows at least three rapid and abrupt short-term events which punctuate the Late-glacial interstadial in the Alboran and Aegean Seas at 14.1−13.9, 13.5−13.4. and 13−12.6kyr BP, and may be related to the Older Dryas, Greenland Interstadial-1c2 (GI-1c2) and the Gerzensee Oscillation respectivelyYou would need to look deeper into this to find out about the temperature change during those periods, and if it there is evidence beyond the local scale. This reference does describe very rapid change in local ocean temperature, but again, neither that paper nor the associated literature go on to describe the rate and extent of global change.
While global temperature records that far back are of course not as accurate, we do appear to know certain things, such as Meltwater pulse 1A causing sea level rise of 50 mm per year, which is over 10 times the current rate.- This does not tell us much of anything about the warming rate. Ice sheet retreat is determined by ice sheet structure and topology first, and temperature changes second. It is universally accepted that the Eurasian and Laurentide ice sheets which collapsed at the time were much less stable than the presently existing Greenland and Antarctica ice sheets. You cannot use the rate of their retreat relative to present as evidence for the rate of warming compared to present. InformationToKnowledge ( talk) 19:57, 9 May 2024 (UTC)
As the world emerged from the last Glacial period, OMZs underwent a large volumetric increase at the beginning of the Bølling-Allerød (B/A), a northern-hemisphere wide warming event, 14.7 ka (Jaccard and Galbraith, 2012; Praetorius et al., 2015) with deleterious consequences for benthic ecosystems (e.g., Moffitt et al., 2015).- AR WG1, 715 InformationToKnowledge ( talk) 20:18, 9 May 2024 (UTC)
New ocean heat content (OHC) reconstructions derived from paleo proxies (Bereiter et al., 2018; Baggenstos et al., 2019; Shackleton et al., 2019; Gebbie, 2021) indicate that the global ocean warmed by 2.57°C ± 0.24°C, at an average rate of about 0.3°C ka–1 (equivalent to an OHC change rate of 1.3 ZJ yr –1) from the LGM (about 20 ka) to the early Holocene (about 10 ka; Section 9.2.2.1 and Figure 9.9). Over the LDT, ocean warming occurred in two stages, offset by some heat loss during the Antarctic Cold Reversal (14.58–12.75 ka). Only during a short period of rapid warming at the end of the Younger Dryas (12.75–11.55 ka) were rates comparable to those observed since the 1970s- AR WG1, 349 InformationToKnowledge ( talk) 19:52, 10 May 2024 (UTC)
Bogazicili ( talk) 17:11, 12 May 2024 (UTC)Recent changes, such as increase in CO2 concentrations and global temperature, "are unprecedented over many centuries to many thousands of years." [AR 6 WG1 SPM-9] Including high emission scenarios, future projections of global temperature and CO2 increase are "similar to those only from many millions of years ago." [AR 6 WG1 Technical Summary p.44]
Suggested change in text for the lead:
Climate change in a broader sense also includes previous long-term changes to Earth's climate. The current rise in global average temperature is more rapid than previous changes, and is primarily caused by humans burning fossil fuels.[3][4]
Though there have been previous periods of climatic change, since the mid-20th century, humans have had unprecedented impact on Earth's climate system and caused change on a global scale.[2]
Climate change in a broader sense also includes previous long-term changes to Earth's climate. The current rise in global average temperature is caused by humans. [1] Resulting changes on Earth's climate system are unprecedented in a long time. [1]
No need for "is primarily caused by humans burning fossil fuels" in the current text since the next sentences in the lead already explain fossil fuels and greenhouse emissions parts. Bogazicili ( talk) 20:25, 8 May 2024 (UTC)
Click at right to show/hide refs
|
---|
References
|
A lot of recent additions by Efbrazil use long in-line citations [64] [65], contrary to Talk:Climate_change/Citation_standards. Consistent citations are a Wikipedia:Featured article criteria. Is there any need for change for this? I think short ones work best for this article, given we cite sources like IPCC sources many times with different page numbers. And the majority of citations are already in that format. Bogazicili ( talk) 20:32, 9 May 2024 (UTC)
142; National Academies 2008, p. 6could be safely cut in favour of AR6 page numbers and the like, but as long as this reference style stays, it'll remain in the same torpor.
I honestly think it's a readability issue, with blue hyperlink and black page numbers, and the text is also black. This is a modified version from a village pump discussion:
Short and long mixed | Long only |
---|---|
The Sun is big.
[1] The Sun is really big.
[2]
[3] Don't look at sun with naked eyes.
[4] The sun is really big and this is coming from several big books.
[5]
[6]
.
|
The Sun is big. [1]: 45 The Sun is really big. [1]: 23 [2]: 250–270 Don't look at sun with naked eyes. [3] The sun is really big and this is coming from several big books. [1]: 107–110 [2]: 50–80 |
You can tell how many times a source is used with Ctrl+F. For the above example, it'd work if you search for "Miller 2005" Bogazicili ( talk) 21:32, 9 May 2024 (UTC)
At issue is two versions of events. There is FAR / Bogazicili text here, sourced to SR15 / page 54, which I just removed as being potentially inaccurate:
The modern observed rise in temperature and CO2 concentrations has been so rapid that even abrupt geophysical events that took place in Earth's history do not approach current rates.
Or there is this text talking about warming following the last ice age. I had added it a while ago in trying to describe the best research on the last ice age. Femke deleted it as recent research, which is fine by me, but I don't know of a more accurate (consensus) science on warming rates following the last ice age:
The warming that followed included a 500 year period when sea levels rose 18 meters (59 ft) [1]
The reason I put the text in I did is that the meltwater pulse seemed like solid, global data. The Bolling-allerod warming article is important to read though. It includes this statement, which contradicts the claim made in SR15:
Records obtained from the Gulf of Alaska show abrupt sea-surface warming of about 3 °C (in less than 90 years), matching ice-core records that register this transition as occurring within decades. [2]
Perhaps the SR15 statement is simply false now as it no longer reflects the latest science. My general view is that we simply should not make claims about how rapid climate change was prior to the anthropocene as the science isn't clear. I'm not saying we should say SR15 is incorrect, but I also don't want to blindly parrot SR15 when what it says is directly contradicted by our own ice age articles on wikipedia. Maybe the SR15 claim still works if it is isolated to CO2 levels and not temperatures.
I'm hoping we can discuss the actual science here rather than wording or what was in FAR or this study or that study. Is there an expert that can say which claim (if any) is correct and why? Until we have consensus on what the science says, I think it is best that we avoid adding stuff to the article about it. I put an ask on the Bølling–Allerød wiki page for experts there to take part in this discussion. Efbrazil ( talk) 17:41, 15 May 2024 (UTC)
References
Bogazicili ( talk) 18:18, 15 May 2024 (UTC)Recent changes, such as increase in CO2 concentrations and global temperature, "are unprecedented over many centuries to many thousands of years." AR6 WG1 SPM-9 Including high emission scenarios, future projections of global temperature and CO2 increase for the upcoming 300 years are "similar to those only from many millions of years ago." AR6 WG1 Technical Summary p.44
Figure TS.1 Changes in atmospheric CO2 and global surface temperature (relative to 1850–1900) from the deep past to the next 300 yearsThere are 2 graphs there. For temperature and CO2 increase. Temperature one would look like this [66] but would go back millions of years and would include 3 future scenarios. I just meant the line graphs, not the warming globe images. I assumed IPCC makes its data available somewhere? Bogazicili ( talk) 17:40, 18 May 2024 (UTC)
Bogazicili ( talk) 19:17, 15 May 2024 (UTC)For example, there is medium confidence that, by 2300, an intermediate scenario14 used in this Report leads to global surface temperatures of [2.3°C to 4.6°C] higher than 1850–1900, similar to the mid-Pliocene Warm Period [2.5°C to 4°C], about 3.2 million years ago, whereas the high CO2 emissions scenario SSP5-8.5 leads to temperatures of [6.6°C to 14.1°C] by 2300, which overlaps with the Early Eocene Climate Optimum [10°C to 18°C], about 50 million years ago. AR6 WG1 Technical Summary pp.43-44
Recent changes, such as increase in CO2 concentrations and global temperature,...in the first sentence to
Recent increases in CO2 concentrations and global temperature...If we want to mention any other unprecedented change/increase in the lead, we should do it explicitly. Then,
I don't know that it is very compelling, as "many centuries" arguably only goes back to the middle agesis certainly not how that statement was intended to be read, but I can see how this wording leaves open that possibility. So, I would like to bring up the following instead:
Over the last 50 years, global surface temperature has increased at an observed rate unprecedented in at least the last two thousand years (medium confidence), and it is more likely than not that no multi-centennial period after the Last Interglacial (roughly 125,000 years ago) was warmer globally than the most recent decade (Cross-Section Box TS.1, Figure 1). During the mid-Pliocene Warm Period, around 3.3–3.0 million years ago, global surface temperature was 2.5°C–4°C warmer, and during the Last Interglacial, it was 0.5°C–1.5°C warmer than 1850–1900- AR6, WG1, TS, 28
The centennial rate of change of CO2 since 1850 has no precedent in at least the past 800,000 years (Figure TS.9), and the fastest rates of change over the last 56 million years were at least a factor of 4 lower- AR6, WG1, TS, 35
By 2019, concentrations of CH4 reached 1866.3 (± 3.3) ppb (Figure TS.9c). The increase since 1750 of 1137
Over the last few million years human beings evolved in a climate that cycled through ice ages, with global average temperature ranging between 1 °C warmer and 5–6 °C colder than current levels. One of the hotter periods was the Last Interglacial between 115,000 and 130,000 years ago, when sea levels were 6 to 9 meters higher than today.
Over the last few million years human beings evolved in a climate that cycled through ice ages, with global average temperature ranging between 1 °C warmer and 5–6 °C colder than current levels. During the Last Interglacial between 115,000 and 130,000 years ago, temperatures were at most 0.5°C warmer than the current levels, yet sea levels were 6 to 9 meters higher than today.
In the long run, sea level rise would amount to 2–3 m (7–10 ft) over the next 2000 years if warming amounts to 1.5 °C (2.7 °F).- is helpful (and also based on AR6), but how to add any of this into that section in a way that reads naturally? InformationToKnowledge ( talk) 04:06, 16 May 2024 (UTC)
Regarding Bølling–Allerød, the graphics don't support the "cancelled out" claim as far as I can tell. The IPCC text doesn't make that claim, and the maps you link to show overall warming (just driven by the northern hemisphere)."Northern-Hemisphere wide" is a very specific phrasing which would not be used by the IPCC if the event was global. When looking at the graphic, you also need to remember that a) the ocean always has the majority of the heat in the Earth system; b) Oceans occupy much larger fraction of the Southern Hemisphere as most landmass is in the North; and c) most map projections inflate the size of the Northern Hemisphere.
The global temperature stack shows a two-step rise, with most warming occurring during and right after the Oldest Dryas and Younger Dryas intervals and relatively little temperature change during the Last Glacial Maximum (LGM), the Bølling–Allerød interval and the early Holocene epoch.
Similarly, although ice-sheet extent and its associated albedo (from ice cover and emergent continental shelves) and orographic forcing decreased through the deglaciation, global ice volume and area changed only slowly or not at all during intervals of pronounced global warming such as the Oldest Dryas and Younger Dryas, and the greatest volume or area loss in fact occurred during intervals of little or no warming around 19 kyr ago and the Bølling–Allerød.
Recent large-scale changes in climate system "are unprecedented in a multi-millennial context." AR6 WG1 Technical Summary p.43
Bogazicili ( talk) 17:36, 18 May 2024 (UTC)With intermediate and high emission scenarios, future projections of global surface temperatures by year 2300 are similar to millions of years ago. AR6 WG1 Technical Summary p.43-44
Ongoing changes in climate have had no precedent in multiple millennia.?
Under high emissions, temperatures would reach levels not seen in millions of years by 2100. Under intermediate emissions, such levels would occur closer to 2300? Maybe this particular page of the TS would not support both sentences, but surely another page of the report would? And it's very likely that there are review papers which also say the same, if necessary. (I know at least one research paper which says this openly, but that is more of a last resort.) InformationToKnowledge ( talk) 01:02, 19 May 2024 (UTC)
Ongoing changes in climate have had no precedent in multiple millenniaand added into the article, since there have been no additional comments. Bogazicili ( talk) 19:19, 2 June 2024 (UTC)
I'm thinking the lead should probably make clear what is unusual about current warming. CO2 levels seem to be the most obvious issue. In the article we say CO2 levels are higher than they have been for 2 million years, so I'm thinking we could bring that fact to the lead, like this:
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to Earth's climate. The current rise in global average temperature is primarily caused by humans burning fossil fuels. Fossil fuel use, deforestation, and some agricultural and industrial practices add to greenhouse gases, notably carbon dioxide and methane. Greenhouse gases absorb some of the heat that the Earth radiates after it warms from sunlight. Larger amounts of these gases trap more heat in Earth's lower atmosphere, causing global warming.. These gases absorb some of the heat that the Earth radiates after it warms from sunlight, warming the lower atmosphere. Carbon dioxide, the primary greenhouse gas driving global warming, has reached levels that are higher than they have been for millions of years.
Efbrazil (
talk) 16:52, 17 May 2024 (UTC)
The current rise- why not "The current increase"?
is primarily caused by humans burning fossil fuels. Fossil fuel use,- any way to avoid this duplication? Perhaps "is primarily caused by greenhouse gas emissions from the consumption of fossil fuels. Deforestation, animal agriculture and certain other agricultural and industrial practices also emit greenhouse gases. These gases absorb..."
some of the heat that the Earth radiates after it warms from sunlight, warming the lower atmosphere.We use warms/warming almost directly after each other. Perhaps use "heating" instead of warming, or some other synonymous word? Further, only a small fraction of warming goes into the lower atmosphere. Can we instead use "heating the ocean and the lower atmosphere"? (A reference to melting ice, which accounts for slightly more heat than the atmosphere, would be nice too, but is probably too difficult to fit in.) InformationToKnowledge ( talk) 14:40, 18 May 2024 (UTC)
I think to get it a little under control we can cut the 200 year part. That time frame is implied by the fact that we are pointing to the burning of fossil fuels earlier in the paragraph.I think that if you want to do that, we should expand one of the preceding sentences a little to clarify the timescale.
The current rise in global average temperature is primarily caused by humans burning fossil fuels.->
The current increase in global average temperature is primarily caused by humans burning fossil fuels since the Industrial Revolution.InformationToKnowledge ( talk) 01:09, 19 May 2024 (UTC)
We must add the new information coming out from the International Labour Organization regarding the effect of climate change on labor, occupational safety and health, and the economy. Since I am a new editor to the page I wanted to give the courtesy of sharing that information first before jumping into any edits.
A report by the United Nations International Labour Organization released in April 2024 found that 22.85 million injuries and 18,970 fatalities in the workplace every year are linked to extreme heat exposure. [ Source: Report found in PDF format on the webpage. Should consider archiving on web archive so that the text and pdf remain stable.]
By 2030, there will be an estimated 2.4 trillion USD financial loss due to heat-related illness, even if we limit the rate of warming to 1.5°C above pre-industrial levels. Furthermore, by 2030, 80 million jobs will be lost due to high temperatures. [ Source]
I believe these facts merit at least their own paragraph because of the specific impact climate change will have on laborers' health in the workplace and therefore on the economy as a whole, as opposed to the broad-based health impacts on human health. Aem832 ( talk) 15:34, 22 May 2024 (UTC)
This is the
talk page for discussing improvements to the
Climate change article. This is not a forum for general discussion of the article's subject. |
Article policies
|
Find sources: Google ( books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL |
This page is not a forum for general discussion about Climate change. Any such comments may be removed or refactored. Please limit discussion to improvement of this article. You may wish to ask factual questions about Climate change at the Reference desk. |
Frequently asked questions To view an answer, click the [show] link to the right of the question. To view references used by an answer, you must also click the [show] for references at the bottom of the FAQ. Q1: Is there really a scientific consensus on climate change?
A1: Yes. The
IPCC findings of recent warming as a result of human influence are explicitly
recognized as the "consensus" scientific view by the science academies of all the major industrialized countries. No scientific body of national or international standing presently rejects the basic findings of human influence on recent climate. This
scientific consensus is supported by over 99% of publishing climate scientists.
[1]
Q2: How can we say climate change is real when it's been so cold in such-and-such a place?
A2: This is why it is termed "global warming", not "(such-and-such a place) warming". Even then, what rises is the average temperature over time – that is, the temperature will fluctuate up and down within the overall rising trend. To give an idea of the relevant time scales, the standard averaging period specified by the World Meteorological Organisation (WMO) is 30 years. Accordingly, the WMO defines climate change as "a statistically significant variation in either the mean state of the climate or in its variability, persisting for an extended period (typically decades or longer)."
[2] Q3: Can't the increase of CO2 be from natural sources, like volcanoes or the oceans?
A3: While these claims are popular among global warming skeptics,
[3]
[4] including academically trained ones,
[5]
[6] they are incorrect. This is known from any of several perspectives:
Q4: I think the article is missing some things, or has some things wrong. Can I change it?
A4: Yes. Keep in mind that your points need to be based on documented evidence from the peer-reviewed literature, or other information that meets standards of
verifiability,
reliability, and
no original research. If you do not have such evidence, more experienced editors may be able to help you find it (or confirm that such evidence does not exist). You are welcome to make such queries on the article's talk page but please keep in mind that the talk page is for discussing improvements to the article, not discussing the topic. There are many forums that welcome general discussions of global warming, but the article talk page is not such a forum. Q5: Why haven't the graphs been updated?
A5: Two reasons:
Q6: Isn't climate change "just a theory"?
A6: People who say this are abusing the word "theory" by
conflating its common meaning with its scientific meaning.
In common usage, "theory" can mean a hunch or guess, but a
scientific theory, roughly speaking, means a coherent set of explanations that is compatible with observations and that allows predictions to be made. That the temperature is rising is an observation. An explanation for this (also known as a
hypothesis) is that the warming is primarily driven by greenhouse gases (such as CO2 and methane) released into the atmosphere by human activity.
Scientific models have been built that predict the rise in temperature and these predictions have matched observations. When scientists gain confidence in a hypothesis because it matches observation and has survived intense scrutiny, the hypothesis may be called a "theory". Strictly speaking, scientific theories are never proven, but the degree of confidence in a theory can be discussed. The scientific models now suggest that it is "extremely likely" (>95%) to "virtually certain" (>99%) that the increases in temperature have been caused by human activity as discussed in the
IPCC Fifth Assessment Report. Global warming via greenhouse gases by human activity is a theory (in the scientific sense), but it is most definitely not just a hunch or guess. Q7: Does methane cause more warming than CO2?
A7: It's true that methane is more potent molecule for molecule. But there's far less of it in the atmosphere, so the total effect is smaller. The atmospheric lifetime of methane (about 10 years) is a lot shorter than that of CO2 (hundreds to thousands of years), so when methane emissions are reduced the concentration in the atmosphere soon falls, whereas CO2 accumulates in the atmosphere over long periods. For details see the
greenhouse gas and
global warming potential articles.
Q8: How can you say there's a consensus when lists of "skeptical scientists" have been compiled?
A8: Consensus is not the same as unanimity, the latter of which is impractical for large groups. Over 99% of publishing climate scientists agree on anthropogenic climate change.
[1] This is an extremely high percentage well past any reasonable threshold for consensus. Any list of "skeptical scientists" would be dwarfed by a comparably compiled list of scientists accepting anthropogenic climate change. Q9: Did climate change end in 1998?
A9: One of the strongest
El Niño events in the instrumental record occurred during late 1997 through 1998, causing a spike in global temperature for 1998. Through the mid-late 2000s this abnormally warm year could be chosen as the starting point for comparisons with later years in order to produce a cooling trend; choosing any other year in the 20th century produced a warming trend. This no longer holds since the mean global temperatures in 2005, 2010, 2014, 2015 and 2016 have all been warmer than 1998.
[12]
More importantly, scientists do not define a "trend" by looking at the difference between two given years. Instead they use methods such as
linear regression that take into account all the values in a series of data. The
World Meteorological Organisation specifies 30 years as the standard averaging period for climate statistics so that year-to-year fluctuations are averaged out;
[2] thus, 10 years isn't long enough to detect a climate trend. Q10: Wasn't Greenland much warmer during the period of Norse settlement?
A10: Some people assume this because of the island's name. In fact the
Saga of Erik the Red tells us Erik named the new colony Greenland because "men will desire much the more to go there if the land has a good name."
[13] Advertising hype was alive and well in 985 AD.
While much of Greenland was and remains under a large ice sheet, the areas of Greenland that were settled by the Norse were coastal areas with fjords that, to this day, remain quite green. You can see the following images for reference:
Q11: Are the IPCC reports prepared by biased UN scientists?
A11: The
IPCC reports are not produced by "UN scientists". The IPCC does not employ the scientists who generate the reports, and it has no control over them. The scientists are internationally recognized experts, most with a long history of successful research in the field. They are employed by various organizations including scientific research institutes, agencies like
NASA and
NOAA, and universities. They receive no extra pay for their participation in the IPCC process, which is considered a normal part of their academic duties. Q12: Hasn't global sea ice increased over the last 30 years?
A12: Measurements show that it has not.
[14] Claims that global sea ice amounts have stayed the same or increased are a result of
cherry picking two data points to compare, while ignoring the real (
strongly statistically significant) downward trend in measurements of global sea ice amounts.
Arctic sea ice cover is declining strongly; Antarctic sea ice cover has had some much smaller increases, though it may or may not be thinning, and the Southern Ocean is warming. The net global ice-cover trend is clearly downwards. Q13: Weren't scientists telling us in the 1970s that the Earth was cooling instead of warming?
A13: They weren't – see the article on
global cooling. An article in the
Bulletin of the American Meteorological Society has reviewed the scientific literature at that time and found that even during the 1970s the prevailing scientific concern was over warming.
[15] The common misperception that cooling was the main concern during the 1970s arose from a few studies that were sensationalized in the popular press, such as a short nine-paragraph article that appeared in Newsweek in 1975.
[16] (
Newsweek eventually apologized for having misrepresented the state of the science in the 1970s.)
[17] The author of that article has repudiated the idea that it should be used to deny global warming.
[18] Q14: Doesn't water vapour cause 98% of the greenhouse effect?
A14: Water vapour is indeed a major greenhouse gas, contributing about 36% to 70% (not 98%) of the total greenhouse effect. But water vapour has a very short atmospheric lifetime (about 10 days), compared with decades to centuries for greenhouse gases like CO2 or nitrous oxide. As a result it is very nearly in a
dynamic equilibrium in the atmosphere, which globally maintains a nearly constant
relative humidity. In simpler terms, any excess water vapour is removed by rainfall, and any deficit of water vapour is replenished by evaporation from the Earth's surface, which literally has oceans of water. Thus water vapour cannot act as a driver of climate change.
Rising temperatures caused by the long-lived greenhouse gases will however allow the atmosphere to hold more vapour. This will lead to an increase in the absolute amount of water vapour in the atmosphere. Since water vapour is itself a greenhouse gas, this is an example of a positive feedback. Thus, whereas water vapour is not a driver of climate change, it amplifies existing trends. Q15: Is the fact that other solar system bodies are warming evidence for a common cause (i.e. the sun)?
A15: While some solar system bodies show evidence of local or global climate change, there is no evidence for a common cause of warming.
Q16: Do scientists support climate change just to get more money?
A16: No,
Q17: Doesn't the climate vary even without human activity?
A17: It does, but the fact that natural variation occurs does not mean that human-induced change cannot also occur. Climate scientists have extensively studied natural causes of climate change (such as orbital changes, volcanism, and solar variation) and have ruled them out as an explanation for the current temperature increase. Human activity is the cause at the 95 to 99 percent confidence level (see the
IPCC Fifth Assessment Report for details). The high level of certainty in this is important to keep in mind to spot mention of natural variation functioning as a
distraction. Q18: Should we include the view that climate change will lead to planetary doom or catastrophe?
A18: This page is about the science of climate change. It doesn't talk about planetary doom or catastrophe. For a technical explanation, see
catastrophic climate change, and for
paleoclimatic examples see
PETM and
great dying. Q19: Is an increase in global temperature of, say, 3 degrees Celsius (5.4 degrees Fahrenheit) important?
A19: Though it may not sound like much, a global temperature rise of 3 degrees Celsius (5.4 degrees Fahrenheit) is huge in climate terms. For example, the sea level rise it would produce would flood coastal cities around the world, which include most large cities.
Q20: Why are certain proposals to change the article discarded, deleted, or ignored? Who is/was
Scibaby?
A20:
Scibaby is/was a
long term abusive
sock-master (or coordinated group of sock masters) who has created
1,027 confirmed sock puppets, another
167 suspected socks, and probably many untagged or unrecognized ones.
This page lists some recent creations. His modus operandi has changed over time, but includes proposing reasonably worded additions on the talk page that only on close examination turn out to be irrelevant, misinterpreted, or give
undue weight to certain aspects. Scibaby is banned, and Scibaby socks are blocked as soon as they are identified. Some editors silently revert his additions, per
WP:DENY, while others still assume good faith even for likely socks and engage them. Q21: What about this really interesting recent peer-reviewed paper I read or read about, that says...?
A21: There are hundreds of peer-reviewed papers published every month in
respected scientific journals such as
Geophysical Research Letters, the
Journal of Climate, and others. We can't include all of them, but the article does include references to individual papers where there is consensus that they best represent the state of the relevant science. This is in accordance with the "due weight" principle (
WP:WEIGHT) of the
Neutral point of view policy and the "Wikipedia is not an indiscriminate collection of information" principle (
WP:IINFO) of the
What Wikipedia is not policy. Q22: Why does the article define "climate change" as a recent phenomenon? Hasn't the planet warmed and cooled before?
A22: Yes, the planet has warmed and cooled before. However, the term "climate change" without further qualification is widely understood to refer to the recent episode and often explicitly connected with the greenhouse effect. Per
WP:COMMONNAME, we use the term in this most common meaning. The article
Climate variability and change deals with the more general concept. Q23: Did the CERN
CLOUD experiment prove that climate change is caused not by human activity but by cosmic rays?
A23: No. For cosmic rays to be causing global warming, all of the following would have to be true, whereas only the italicized one was tested in the 2011 experiment:
[28]
Q24: I read that something can't fix climate change. Is this true?
A24: Yes, this is true for all plausible single things including: "electric cars", "planting trees", "low-carbon technology", "renewable energy", "Australia", "capitalism", "the doom & gloom approach", "a Ph.D. in thermodynamics". Note that it is problematic to use the word "fix" regarding climate change, as returning the climate to its pre-industrial state currently appears to be feasible only over a timeframe of thousands of years. Current efforts are instead aimed at mitigating (meaning limiting) climate change. Mitigation is strived for through the combination of many different things. See
Climate change mitigation for details. References
|
This article is written in British English, which has its own spelling conventions (colour, travelled, centre, defence, artefact, analyse) and some terms that are used in it may be different or absent from other varieties of English. According to the relevant style guide, this should not be changed without broad consensus. |
Climate change is a featured article; it (or a previous version of it) has been identified as one of the best articles produced by the Wikipedia community. Even so, if you can update or improve it, please do so. | ||||||||||||||||||||||||||||
This article appeared on Wikipedia's Main Page as Today's featured article on June 21, 2006, and on October 31, 2021. | ||||||||||||||||||||||||||||
|
This
level-3 vital article is rated FA-class on Wikipedia's
content assessment scale. It is of interest to multiple WikiProjects. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
This article has been
mentioned by multiple media organizations:
|
The
contentious topics procedure applies to this page. This page is related to
climate change, which has been
designated as a contentious topic. Editors who repeatedly or seriously fail to adhere to the purpose of Wikipedia, any expected standards of behaviour, or any normal editorial process may be blocked or restricted by an administrator. Editors are advised to familiarise themselves with the contentious topics procedures before editing this page. |
Other talk page banners | |||||||||||||
|
On 3 August 2020, it was proposed that this article be moved from Global warming to Climate change. The result of the discussion was moved. |
|
Index
1,
2,
3,
4,
5,
6,
7,
8,
9,
10 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 41, 42, 43, 44, 45, 46, 47, 48, 49, 50 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 61, 62, 63, 64, 65, 66, 67, 68, 69, 70 71, 72, 73, 74, 75, 76, 77, 78, 79, 80 81, 82, 83, 84, 85, 86, 87, 88, 89, 90 91, 92, 93, 94, 95 |
This page has archives. Sections may be automatically archived by Lowercase sigmabot III when more than 8 sections are present. |
Which of the following sections should be used in the Food and health section?
Robert McClenon ( talk) 04:47, 17 April 2024 (UTC) RfC restarted Bogazicili ( talk) 17:24, 18 May 2024 (UTC)
A.
Human health
The World Health Organization (WHO) calls climate change the greatest threat to global health in the 21st century. [1] Over 100 scientists writing in The Lancet have warned about the irreversible harms it poses. [2] According to the World Economic Forum, the most likely future scenario is of 14.5 million deaths caused by climate change by 2050. [3] Of those, 8.5 million deaths are associated with flooding, mostly because flooded areas expand the range of malaria. By 2050, the range of vector-borne diseases may expand to reach 500 million more people. Saltwater intrusion caused by sea level rise will also add over 800,000 cases of hypertension in coastal areas. [4]
Under the same scenario, around 1.6 million people will die in heatwaves by 2050, primarily those aged 65 and older, and 300,000 more will be killed by wildfires. [5] 30% of the global population currently live in areas where extreme heat and humidity are already associated with excess deaths. [6] By 2100, 50% to 75% of the global population would live in such areas. [7] p. 988 These and other climate change impacts are also expected to substantially increase the burden of stress-related mental health conditions. [8] The overall healthcare costs from climate change impacts would exceed 1$ trillion by 2050. [9] If the emissions continue to increase for the rest of century, then over 9 million climate-related deaths would occur annually by 2100. p.63
Food supply
Climate change has strong impacts on agriculture in the low latitudes, where it threatens both staple crops and important cash crops like cocoa and coffee. p.788 Agriculture will experience yield gains at high latitudes, but will also become more vulnerable to pests and pathogens. p.794 Extreme weather events adversely affect both food and water security, and climate change increases their frequency. p.9 Food prices spike after climate shocks. p.794 An increase in drought in certain regions could cause 3.2 million deaths from malnutrition by 2050, primarily in children under five. Many more children would grow up stunted as the result. [10] Under higher warming, global livestock headcounts could decline by 7-10% by 2050, as less animal feed will be available. p.748 Marine animal biomass decreases by 5% with every degree of warming, reducing fishery yields. p.718
In isolation, climate change is expected to increase the risk of hunger for 8 to 80 million people by 2050. p.725 However, total crop yields have been increasing since the middle of the 20th century due to agricultural improvements, and in spite of climate change. [11] p.832 By 2050, the overall number of people suffering from undernourishment and the associated health conditions is likely to decrease by tens to hundreds of millions. [12] Food security only worsens by 2050 in some combinations of severe climate change and low socioeconomic development, [13] but if the emissions remain high, it will likely decrease after 2050. This would be due to diminishing fisheries and livestock counts, and due to more frequent and severe crop failures. p.797
B.
The World Health Organization calls climate change the greatest threat to global health in the 21st century. [14] Over 100 scientists writing in The Lancet have warned about the irreversible harms it poses. [15] Extreme weather events affect public health, and food and water security. [16] [17] p. 9 Temperature extremes lead to increased illness and death. [18] [19] Climate change increases the intensity and frequency of extreme weather events. [20] p.9 It can affect transmission of infectious diseases. [21] [22] According to the World Economic Forum, 14.5 million more deaths are expected due to climate change by 2050. [23] 30% of the global population currently live in areas where extreme heat and humidity are already associated with excess deaths. [24] By 2100, 50% to 75% of the global population would live in such areas. [25] p. 988
While total crop yields have been increasing in the past 50 years due to agricultural improvements, climate change has already slowed the rate of yield growth. p. 9 Fisheries have been negatively affected in multiple regions. p. 9 Agricultural productivity was negatively affected in mid- and low-latitude areas, while some high latitude areas were positively affected. p.9 An increase in drought in certain regions could cause 3.2 million deaths from malnutrition by 2050 and stunting in children. [26] With 2C warming, global livestock headcounts could decline by 7-10% by 2050, as less animal feed will be available. p.748 If the emissions continue to increase for the rest of century, then over 9 million climate-related deaths would occur annually by 2100. p.63
C. Something else - Please provide a complete section.
Please enter A, B, or C (with the text) in the Survey. Please do not respond to the statements of other editors in the Survey.
Climate change is the greatest threat to global health in the 21st century. [27]. [28] [29] [30] p. 9 [31] [32] Climate change increases the intensity and frequency of extreme weather events [33] p.9 leading to increased illness and death. [34] [35]
Currently
- 30% of the global population live in extreme heat and humidity associated with excess deaths. [36]
- Food prices spike after climate shocks. p.794
- Climate change has slowed the rate of yield growth. p. 9 [37] p.832 p.9 p.788
- Fisheries have been negatively affected in multiple regions. p. 9
2050, The most likely scenario
- 14.5 million deaths [38] by flooding and malaria [39], malnutrition by droughts, heatwaves, wildfires. [40]
- risk of hunger for 8 to 80 million people. p.725 Many children grow up stunted. [41] p.797 [42]
- Agriculture yield gains at high latitudes, but more vulnerable to pests and pathogens. p.794
- With 2C warming, global livestock headcounts declines by 7-10%, as less animal feed will be available. p.748
- Marine animal biomass decreases by 5% with every degree of warming, reducing fishery yields. p.718
2100, The most likely scenario
Uwappa ( talk) 09:03, 19 April 2024 (UTC)
Climate change is the greatest threat to global health in the 21st century. [45], posing irreversible harms. [46] Climate change increases the intensity and frequency of extreme weather events [47] p.9, affecting public health, and food and water security. [48] [49] p. 9 [50] [51] Temperature extremes lead to increased illness and death. [52] [53]
- Currently
- 30% of the global population live in areas where extreme heat and humidity are already associated with excess deaths. [54] While total crop yields have been increasing in the past 50 years due to agricultural improvements, climate change has already slowed the rate of yield growth. p. 9 p.9 Fisheries have been negatively affected in multiple regions. p. 9
- By 2050
- 14.5 million more deaths are expected. [55]. With 2C warming, global livestock headcounts could decline by 7-10%, as less animal feed will be available. p.748 An increase in drought in certain regions could cause 3.2 million deaths from malnutrition and stunting in children. [56]
- By 2100
- 50% to 75% of the global population would live in extreme heat. [57] p. 988 If the emissions continue to increase for the rest of century, then over 9 million climate-related deaths would occur annually. p.63
Uwappa ( talk) 12:03, 29 April 2024 (UTC)
@ Efbrazil: I understand your (and others') objections to option A based on length, but remember this discussion from the start of February, when many of us were looking to cut material from the "Causes" section, and you had yourself proposed removing 4-5 paragraphs? This option is still very much available: we simply couldn't do it at the time because Causes of climate change wasn't a live article yet, but it is done now. In fact, it often intentionally duplicates the current article, precisely to make it easier to cut from here. Thus, if we do in fact remove 4-5 paragraphs from causes but add 2 paragraphs here, on food and health, we will still ultimately have a shorter article.
I also think that every sentence in A provides unique and distinct information our readers would likely not know otherwise, but then again, I would think that as its author. I realize that all the editors who have so far voted for B may still want the section to be shorter rather than longer even after we condense "Causes". If so, which parts of A would you consider to be the most "skippable"? InformationToKnowledge ( talk) 17:25, 22 April 2024 (UTC)
InformationToKnowledge had also argued about removing Effects of climate change on human health as an articleI would like to clarify that my proposal was to merge that with the general Effects of climate change - following the logic that once we strip out the material from the article that appears to lack widespread support, such as the "people falling through thinner ice on frozen rivers" thing, there wouldn't be much left that would not be better covered in either that article, Climate change and infectious diseases or Psychological impact of climate change.
I'm opposed to giving more weight to human impacts than we are giving to nature and wildlife.Well, if that is your main objection, then once we remove 4-5 paragraphs from "Causes", that would leave us enough space to both have 4 paragraphs on food and health and to add 2-3 paragraphs to "Nature and wildlife". Considering the work I have done to date on articles such as Extinction risk from climate change or Effects of climate change on biomes (admittedly, more of a work in progress), it wouldn't be overly difficult for me to find reliably referenced material to complement the two paragraphs already present.
An expert elicitation concluded that the role of climate change in armed conflict has been small compared to factors such as socio-economic inequality and state capabilities.seem very awkward to say the least, and could be cut at least in part, if not fully. We have already argued over the limited reliability of this passage -
In some regions, the rise in temperature and humidity may be too severe for humans to adapt to. With worst-case climate change, models project that almost one-third of humanity might live in Sahara-like uninhabitable and extremely hot climates.as well. There is most likely room to condense a paragraph or two there - and then the entire section devoted to impact on humans would be of similar size to "Nature and wildlife" once that is expanded by several paragraphs - likely even after "Food and health" is expanded to four paragraphs, and certainly if it stays at two.
B I could live with, but would want 4 sentences cut that are redundant with other areas or are just generally alarmist rather than informative.Would it be those four sentences, by any chance?
Extreme weather events affect public health, and food and water security.[92][93]p. 9 Temperature extremes lead to increased illness and death.[94][95] Climate change increases the intensity and frequency of extreme weather events.[96]p.9 It can affect transmission of infectious diseases.
Proposal A gets too far into the weeds for me and causes that word count imbalance with the natural world.Well, it's been said already that expanding the natural world in parallel would be one way to address the latter objection. As for the former, that's not really useful feedback. Can you at least identify the sentences you take an issue with, similar to what you have done for B?
On balance, I think the existing text on page is not bad. It does a good job of raising various issues without making dubious claims.-Not really. As we have discussed exhaustively on this page in February and March, several sentences are likely to be fairly misleading for a typical reader. I.e.
Climate change is affecting food security. It has caused reduction in global yields of maize, wheat, and soybeans between 1981 and 2010.- The straightforward read of that paragraph is that the current/2010 yields of those crops are lower than they were in the 1980s - and it would be completely wrong, because the comparison is drawn with the counterfactual present where climate change was not happening, while a clear increase had occurred in the real world.
Up to an additional 183 million people worldwide, particularly those with lower incomes, are at risk of hunger as a consequence of these impacts.- This sentence does not even specify anything. Up to 183 million by when? By next year? In 10 years' time? By 2050? (the correct answer). By 2100? Once climate change passes 2 degrees? Once it is at 6 degrees? Is it the maximum possible impact on hunger? This sentence is so vague that all these readings are equally valid. And again, this finding is relative to a counterfactual 2050, which is not very useful to general readers, which is why A has those two detailed sentences covering the actual projections relative to the present instead.
Crop production will probably be negatively affected in low-latitude countries, while effects at northern latitudes may be positive or negative.- I am surprised you don't seem to consider this sentence "wishy-washy" or too detailed.
As for cuts from version B, the 4 sentences you point to are generally fluffy and could be be folded into other sentences.I am glad you agree on this, but Bogazicili has been fairly insistent on those specific phrasings, leading up to the DRN.
This isn't even specific to human health or agriculture. Too vague and unnecessary- Well, this phrasing comes from the title, which is The 2023 report of the Lancet Countdown on health and climate change: the imperative for a health-centred response in a world facing irreversible harms, and we both felt it was important to cite it here. I suppose we can rewrite this sentence with one or more findings from that report's summary graphic, but it might be best if you can specify which one you wouldn't oppose for one reason or another.
Almost all food scarcity is due to distribution issues, and "could" is wishy washy. Why not make a clear claim about agricultural output instead?- It is "could" to acknowledge that these projections are not set in stone (same point you were making earlier), and the number is for one scenario of several. However, A's final paragraph does discuss agricultural output. Would you prefer some variation of that wording?
Here we have something specific and probably valid, but not interesting given the context.Well, livestock is an important (even if technically skippable) part of the global food system, with a role comparable to fishing, so it makes no sense to mention one but not the other. Not to mention that an effective decimation is not tiny by any means. Literally the next sentence after that figure in the AR6 is:
Changes to African grassland productivity will have substantial, negative impacts on theI cite this in Effects of climate change on livestock, but thought that it is "not global enough" for this section. However, I suppose it can be rephrased as
With 2C warming, global livestock headcounts are likely to decline by 7-10% by 2050, affecting (can't think of a stronger word right now) the livelihoods of over 180 million people.
Why focus on a scenario where emissions continue increasing for the rest of the century, particularly as we don't say how much even,- I consider this a better phrasing than "high-emission scenario" or "worst-case climate change scenario" or the like. People could have vastly different ideas about what those mean, while this wording is immediately much clearer.
...and then attach a bs number to it? Nobody is predicting RCP 8.5 at this time.- So, you consider this alarmist? I actually view it the other way around. Too many people nowadays appear to believe that climate change would lead to billions dying, global collapse, etc. in the fairly near future. (See Climate change and civilizational collapse#Public opinion for the closest we have to objective evidence on the subject.) Thus, presenting this high-emission figure (again, from the AR6) as the "upper bound" for 2100 is actually likely to surprise a lot of people as "too low" - and those are the people who definitely need to see this, and are likely to scroll past the rest of the article and persist in their thinking otherwise. InformationToKnowledge ( talk) 20:16, 27 April 2024 (UTC)
By 2050, 14.5 million deaths are likely, including 8.5 million from flooding and waterborne [water-associated?], 3.2 million from malnutrition due to droughts, 1.6 million from heatwaves by 2050 and 300,000 from wildfires.And again, I would not want to skip over the rather important situation where the bulk of projections say food supply would improve by 2050. InformationToKnowledge ( talk) 19:57, 2 May 2024 (UTC)
Uwappa, would you mind striking down your earlier comment in the survey section above with <s></s>? It looks like you voted twice now. Or make a comment that you made an alternate suggestion? Bogazicili ( talk) 15:21, 3 May 2024 (UTC)
I would prefer the more concise B given we have {{ main article}} links for readers seeking more detail. However, I find that B does not convey the same meaning as A, or even the existing wording: B currently states "Agricultural productivity was negatively affected in mid- and low-latitude areas, while some high latitude areas were positively affected". This gives the impression that agriculture in the high latitudes may only be positively affected, which does not contain the nuance that A has ("Agriculture will experience yield gains at high latitudes, but will also become more vulnerable to pests and pathogens"); the existing wording ("effects at northern latitudes may be positive or negative") shows this duality better (though "northern" should be reworded to "higher"). ~ KN2731 { talk · contribs} 11:55, 6 May 2024 (UTC)
Respectfully, I have learned the most truth about climate and the current climate change from Ben Davidson's https://www.youtube.com/@Suspicious0bservers/featured and Thunderbolts Project https://www.youtube.com/@ThunderboltsProject/playlists
They make the whole picture fit together better than average information sources. With Respect Eva Zdrava 46.248.93.31 ( talk) 15:06, 21 April 2024 (UTC)
This article was the subject of a Wiki Education Foundation-supported course assignment, between 16 January 2024 and 11 May 2024. Further details are available on the course page. Student editor(s): Floralepe ( article contribs).
— Assignment last updated by LynSchwendy ( talk) 03:29, 14 May 2024 (UTC)
I don't know that the claim we make in the lead is correct. The IPCC source used to back the statement is blurring the issue of CO2 rise and temperature rise. The claim we make in the lead is exclusive to temperature.
The article on Bølling–Allerød warming appears to contradict the warming claim. Specifically, it says that at the end of the last ice age there was 3 C of warming in arctic waters within a period of 90 years. While global temperature records that far back are of course not as accurate, we do appear to know certain things, such as Meltwater pulse 1A causing sea level rise of 50 mm per year, which is over 10 times the current rate.
I don't know that we have enough information to uphold the claim we are making here in the lead. Most prehistoric temperature records do not have a resolution sufficient to make comparisons to modern times, and as recently as the last ice age there appear to be conflicting claims. Efbrazil ( talk) 00:08, 8 May 2024 (UTC)
Since 1970 the global average temperature has been rising at a rate of 1.7 °C per century, compared to a long-term decline over the past 7,000 years at a baseline rate of 0.01 °C per century (NOAA, 2016; Marcott et al., 2013). These global-level rates of human-driven change far exceed the rates of change driven by geophysical or biosphere forces that have altered the Earth System trajectory in the past (e.g., Summerhayes, 2015; Foster et al., 2017); even abrupt geophysical events do not approach current rates of human-driven change.
A.2 The scale of recent changes across the climate system as a whole and the present state of many aspects of the climate system are unprecedented over many centuries to many thousands of years.
{Cross-Chapter Box 2.1, 2.2, 2.3, 5.1} (Figure SPM.1)
A.2.1 In 2019, atmospheric CO2 concentrations were higher than at any time in at least 2 million years (high confidence), and concentrations of CH4 and N2O were higher than at any time in at least 800,000 years (very high confidence). Since 1750, increases in CO2 (47%) and CH4 (156%) concentrations far exceed, and increases in N2O (23%) are similar to, the natural multi-millennial changes between glacial and interglacial periods over at least the past 800,000 years (very high confidence).
{2.2, 5.1, TS.2.2}
A.2.2 Global surface temperature has increased faster since 1970 than in any other 50-year period over at least the last 2000 years (high confidence). Temperatures during the most recent decade (2011–2020) exceed those of the most recent multi-century warm period, around 6500 years ago13 [0.2°C to 1°C relative to 1850–1900] (medium confidence). Prior to that, the next most recent warm period was about 125,000 years ago when the multi-century temperature [0.5°C to 1.5°C relative to 1850–1900] overlaps the observations of the most recent decade (medium confidence).
{Cross-Chapter Box 2.1, 2.3, Cross-Section Box TS.1} (Figure SPM.1)
andis doing a lot of work there, as it's much easier to show GHG emissions are unprecedented. Still, I would be okay restoring that sentence, cited to SR15, and remove the lead sentence. —Femke 🐦 ( talk) 19:35, 8 May 2024 (UTC)
The article on Bølling–Allerød warming appears to contradict the warming claim. Specifically, it says that at the end of the last ice age there was 3 C of warming in arctic waters within a period of 90 years.- I thought you would know we should not cite our own articles - particularly not when they are C-level. Have you actually evaluated the claim? The reference cited does not appear to say anything of a kind, although half of it is paywalled.
Are there any sources about global average increase in Bølling–Allerød warming?I still cannot find an exact figure for now: what I did find, however, was an indication that the warming was limited to the Northern Hemisphere, while the Southern Hemisphere cooled. Figure c) on the lower-left appears to show this the best. There is also no other mention of a 90-year interval specifically: the closest might be in this reference:
The results obtained with three methods shows at least three rapid and abrupt short-term events which punctuate the Late-glacial interstadial in the Alboran and Aegean Seas at 14.1−13.9, 13.5−13.4. and 13−12.6kyr BP, and may be related to the Older Dryas, Greenland Interstadial-1c2 (GI-1c2) and the Gerzensee Oscillation respectivelyYou would need to look deeper into this to find out about the temperature change during those periods, and if it there is evidence beyond the local scale. This reference does describe very rapid change in local ocean temperature, but again, neither that paper nor the associated literature go on to describe the rate and extent of global change.
While global temperature records that far back are of course not as accurate, we do appear to know certain things, such as Meltwater pulse 1A causing sea level rise of 50 mm per year, which is over 10 times the current rate.- This does not tell us much of anything about the warming rate. Ice sheet retreat is determined by ice sheet structure and topology first, and temperature changes second. It is universally accepted that the Eurasian and Laurentide ice sheets which collapsed at the time were much less stable than the presently existing Greenland and Antarctica ice sheets. You cannot use the rate of their retreat relative to present as evidence for the rate of warming compared to present. InformationToKnowledge ( talk) 19:57, 9 May 2024 (UTC)
As the world emerged from the last Glacial period, OMZs underwent a large volumetric increase at the beginning of the Bølling-Allerød (B/A), a northern-hemisphere wide warming event, 14.7 ka (Jaccard and Galbraith, 2012; Praetorius et al., 2015) with deleterious consequences for benthic ecosystems (e.g., Moffitt et al., 2015).- AR WG1, 715 InformationToKnowledge ( talk) 20:18, 9 May 2024 (UTC)
New ocean heat content (OHC) reconstructions derived from paleo proxies (Bereiter et al., 2018; Baggenstos et al., 2019; Shackleton et al., 2019; Gebbie, 2021) indicate that the global ocean warmed by 2.57°C ± 0.24°C, at an average rate of about 0.3°C ka–1 (equivalent to an OHC change rate of 1.3 ZJ yr –1) from the LGM (about 20 ka) to the early Holocene (about 10 ka; Section 9.2.2.1 and Figure 9.9). Over the LDT, ocean warming occurred in two stages, offset by some heat loss during the Antarctic Cold Reversal (14.58–12.75 ka). Only during a short period of rapid warming at the end of the Younger Dryas (12.75–11.55 ka) were rates comparable to those observed since the 1970s- AR WG1, 349 InformationToKnowledge ( talk) 19:52, 10 May 2024 (UTC)
Bogazicili ( talk) 17:11, 12 May 2024 (UTC)Recent changes, such as increase in CO2 concentrations and global temperature, "are unprecedented over many centuries to many thousands of years." [AR 6 WG1 SPM-9] Including high emission scenarios, future projections of global temperature and CO2 increase are "similar to those only from many millions of years ago." [AR 6 WG1 Technical Summary p.44]
Suggested change in text for the lead:
Climate change in a broader sense also includes previous long-term changes to Earth's climate. The current rise in global average temperature is more rapid than previous changes, and is primarily caused by humans burning fossil fuels.[3][4]
Though there have been previous periods of climatic change, since the mid-20th century, humans have had unprecedented impact on Earth's climate system and caused change on a global scale.[2]
Climate change in a broader sense also includes previous long-term changes to Earth's climate. The current rise in global average temperature is caused by humans. [1] Resulting changes on Earth's climate system are unprecedented in a long time. [1]
No need for "is primarily caused by humans burning fossil fuels" in the current text since the next sentences in the lead already explain fossil fuels and greenhouse emissions parts. Bogazicili ( talk) 20:25, 8 May 2024 (UTC)
Click at right to show/hide refs
|
---|
References
|
A lot of recent additions by Efbrazil use long in-line citations [64] [65], contrary to Talk:Climate_change/Citation_standards. Consistent citations are a Wikipedia:Featured article criteria. Is there any need for change for this? I think short ones work best for this article, given we cite sources like IPCC sources many times with different page numbers. And the majority of citations are already in that format. Bogazicili ( talk) 20:32, 9 May 2024 (UTC)
142; National Academies 2008, p. 6could be safely cut in favour of AR6 page numbers and the like, but as long as this reference style stays, it'll remain in the same torpor.
I honestly think it's a readability issue, with blue hyperlink and black page numbers, and the text is also black. This is a modified version from a village pump discussion:
Short and long mixed | Long only |
---|---|
The Sun is big.
[1] The Sun is really big.
[2]
[3] Don't look at sun with naked eyes.
[4] The sun is really big and this is coming from several big books.
[5]
[6]
.
|
The Sun is big. [1]: 45 The Sun is really big. [1]: 23 [2]: 250–270 Don't look at sun with naked eyes. [3] The sun is really big and this is coming from several big books. [1]: 107–110 [2]: 50–80 |
You can tell how many times a source is used with Ctrl+F. For the above example, it'd work if you search for "Miller 2005" Bogazicili ( talk) 21:32, 9 May 2024 (UTC)
At issue is two versions of events. There is FAR / Bogazicili text here, sourced to SR15 / page 54, which I just removed as being potentially inaccurate:
The modern observed rise in temperature and CO2 concentrations has been so rapid that even abrupt geophysical events that took place in Earth's history do not approach current rates.
Or there is this text talking about warming following the last ice age. I had added it a while ago in trying to describe the best research on the last ice age. Femke deleted it as recent research, which is fine by me, but I don't know of a more accurate (consensus) science on warming rates following the last ice age:
The warming that followed included a 500 year period when sea levels rose 18 meters (59 ft) [1]
The reason I put the text in I did is that the meltwater pulse seemed like solid, global data. The Bolling-allerod warming article is important to read though. It includes this statement, which contradicts the claim made in SR15:
Records obtained from the Gulf of Alaska show abrupt sea-surface warming of about 3 °C (in less than 90 years), matching ice-core records that register this transition as occurring within decades. [2]
Perhaps the SR15 statement is simply false now as it no longer reflects the latest science. My general view is that we simply should not make claims about how rapid climate change was prior to the anthropocene as the science isn't clear. I'm not saying we should say SR15 is incorrect, but I also don't want to blindly parrot SR15 when what it says is directly contradicted by our own ice age articles on wikipedia. Maybe the SR15 claim still works if it is isolated to CO2 levels and not temperatures.
I'm hoping we can discuss the actual science here rather than wording or what was in FAR or this study or that study. Is there an expert that can say which claim (if any) is correct and why? Until we have consensus on what the science says, I think it is best that we avoid adding stuff to the article about it. I put an ask on the Bølling–Allerød wiki page for experts there to take part in this discussion. Efbrazil ( talk) 17:41, 15 May 2024 (UTC)
References
Bogazicili ( talk) 18:18, 15 May 2024 (UTC)Recent changes, such as increase in CO2 concentrations and global temperature, "are unprecedented over many centuries to many thousands of years." AR6 WG1 SPM-9 Including high emission scenarios, future projections of global temperature and CO2 increase for the upcoming 300 years are "similar to those only from many millions of years ago." AR6 WG1 Technical Summary p.44
Figure TS.1 Changes in atmospheric CO2 and global surface temperature (relative to 1850–1900) from the deep past to the next 300 yearsThere are 2 graphs there. For temperature and CO2 increase. Temperature one would look like this [66] but would go back millions of years and would include 3 future scenarios. I just meant the line graphs, not the warming globe images. I assumed IPCC makes its data available somewhere? Bogazicili ( talk) 17:40, 18 May 2024 (UTC)
Bogazicili ( talk) 19:17, 15 May 2024 (UTC)For example, there is medium confidence that, by 2300, an intermediate scenario14 used in this Report leads to global surface temperatures of [2.3°C to 4.6°C] higher than 1850–1900, similar to the mid-Pliocene Warm Period [2.5°C to 4°C], about 3.2 million years ago, whereas the high CO2 emissions scenario SSP5-8.5 leads to temperatures of [6.6°C to 14.1°C] by 2300, which overlaps with the Early Eocene Climate Optimum [10°C to 18°C], about 50 million years ago. AR6 WG1 Technical Summary pp.43-44
Recent changes, such as increase in CO2 concentrations and global temperature,...in the first sentence to
Recent increases in CO2 concentrations and global temperature...If we want to mention any other unprecedented change/increase in the lead, we should do it explicitly. Then,
I don't know that it is very compelling, as "many centuries" arguably only goes back to the middle agesis certainly not how that statement was intended to be read, but I can see how this wording leaves open that possibility. So, I would like to bring up the following instead:
Over the last 50 years, global surface temperature has increased at an observed rate unprecedented in at least the last two thousand years (medium confidence), and it is more likely than not that no multi-centennial period after the Last Interglacial (roughly 125,000 years ago) was warmer globally than the most recent decade (Cross-Section Box TS.1, Figure 1). During the mid-Pliocene Warm Period, around 3.3–3.0 million years ago, global surface temperature was 2.5°C–4°C warmer, and during the Last Interglacial, it was 0.5°C–1.5°C warmer than 1850–1900- AR6, WG1, TS, 28
The centennial rate of change of CO2 since 1850 has no precedent in at least the past 800,000 years (Figure TS.9), and the fastest rates of change over the last 56 million years were at least a factor of 4 lower- AR6, WG1, TS, 35
By 2019, concentrations of CH4 reached 1866.3 (± 3.3) ppb (Figure TS.9c). The increase since 1750 of 1137
Over the last few million years human beings evolved in a climate that cycled through ice ages, with global average temperature ranging between 1 °C warmer and 5–6 °C colder than current levels. One of the hotter periods was the Last Interglacial between 115,000 and 130,000 years ago, when sea levels were 6 to 9 meters higher than today.
Over the last few million years human beings evolved in a climate that cycled through ice ages, with global average temperature ranging between 1 °C warmer and 5–6 °C colder than current levels. During the Last Interglacial between 115,000 and 130,000 years ago, temperatures were at most 0.5°C warmer than the current levels, yet sea levels were 6 to 9 meters higher than today.
In the long run, sea level rise would amount to 2–3 m (7–10 ft) over the next 2000 years if warming amounts to 1.5 °C (2.7 °F).- is helpful (and also based on AR6), but how to add any of this into that section in a way that reads naturally? InformationToKnowledge ( talk) 04:06, 16 May 2024 (UTC)
Regarding Bølling–Allerød, the graphics don't support the "cancelled out" claim as far as I can tell. The IPCC text doesn't make that claim, and the maps you link to show overall warming (just driven by the northern hemisphere)."Northern-Hemisphere wide" is a very specific phrasing which would not be used by the IPCC if the event was global. When looking at the graphic, you also need to remember that a) the ocean always has the majority of the heat in the Earth system; b) Oceans occupy much larger fraction of the Southern Hemisphere as most landmass is in the North; and c) most map projections inflate the size of the Northern Hemisphere.
The global temperature stack shows a two-step rise, with most warming occurring during and right after the Oldest Dryas and Younger Dryas intervals and relatively little temperature change during the Last Glacial Maximum (LGM), the Bølling–Allerød interval and the early Holocene epoch.
Similarly, although ice-sheet extent and its associated albedo (from ice cover and emergent continental shelves) and orographic forcing decreased through the deglaciation, global ice volume and area changed only slowly or not at all during intervals of pronounced global warming such as the Oldest Dryas and Younger Dryas, and the greatest volume or area loss in fact occurred during intervals of little or no warming around 19 kyr ago and the Bølling–Allerød.
Recent large-scale changes in climate system "are unprecedented in a multi-millennial context." AR6 WG1 Technical Summary p.43
Bogazicili ( talk) 17:36, 18 May 2024 (UTC)With intermediate and high emission scenarios, future projections of global surface temperatures by year 2300 are similar to millions of years ago. AR6 WG1 Technical Summary p.43-44
Ongoing changes in climate have had no precedent in multiple millennia.?
Under high emissions, temperatures would reach levels not seen in millions of years by 2100. Under intermediate emissions, such levels would occur closer to 2300? Maybe this particular page of the TS would not support both sentences, but surely another page of the report would? And it's very likely that there are review papers which also say the same, if necessary. (I know at least one research paper which says this openly, but that is more of a last resort.) InformationToKnowledge ( talk) 01:02, 19 May 2024 (UTC)
Ongoing changes in climate have had no precedent in multiple millenniaand added into the article, since there have been no additional comments. Bogazicili ( talk) 19:19, 2 June 2024 (UTC)
I'm thinking the lead should probably make clear what is unusual about current warming. CO2 levels seem to be the most obvious issue. In the article we say CO2 levels are higher than they have been for 2 million years, so I'm thinking we could bring that fact to the lead, like this:
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to Earth's climate. The current rise in global average temperature is primarily caused by humans burning fossil fuels. Fossil fuel use, deforestation, and some agricultural and industrial practices add to greenhouse gases, notably carbon dioxide and methane. Greenhouse gases absorb some of the heat that the Earth radiates after it warms from sunlight. Larger amounts of these gases trap more heat in Earth's lower atmosphere, causing global warming.. These gases absorb some of the heat that the Earth radiates after it warms from sunlight, warming the lower atmosphere. Carbon dioxide, the primary greenhouse gas driving global warming, has reached levels that are higher than they have been for millions of years.
Efbrazil (
talk) 16:52, 17 May 2024 (UTC)
The current rise- why not "The current increase"?
is primarily caused by humans burning fossil fuels. Fossil fuel use,- any way to avoid this duplication? Perhaps "is primarily caused by greenhouse gas emissions from the consumption of fossil fuels. Deforestation, animal agriculture and certain other agricultural and industrial practices also emit greenhouse gases. These gases absorb..."
some of the heat that the Earth radiates after it warms from sunlight, warming the lower atmosphere.We use warms/warming almost directly after each other. Perhaps use "heating" instead of warming, or some other synonymous word? Further, only a small fraction of warming goes into the lower atmosphere. Can we instead use "heating the ocean and the lower atmosphere"? (A reference to melting ice, which accounts for slightly more heat than the atmosphere, would be nice too, but is probably too difficult to fit in.) InformationToKnowledge ( talk) 14:40, 18 May 2024 (UTC)
I think to get it a little under control we can cut the 200 year part. That time frame is implied by the fact that we are pointing to the burning of fossil fuels earlier in the paragraph.I think that if you want to do that, we should expand one of the preceding sentences a little to clarify the timescale.
The current rise in global average temperature is primarily caused by humans burning fossil fuels.->
The current increase in global average temperature is primarily caused by humans burning fossil fuels since the Industrial Revolution.InformationToKnowledge ( talk) 01:09, 19 May 2024 (UTC)
We must add the new information coming out from the International Labour Organization regarding the effect of climate change on labor, occupational safety and health, and the economy. Since I am a new editor to the page I wanted to give the courtesy of sharing that information first before jumping into any edits.
A report by the United Nations International Labour Organization released in April 2024 found that 22.85 million injuries and 18,970 fatalities in the workplace every year are linked to extreme heat exposure. [ Source: Report found in PDF format on the webpage. Should consider archiving on web archive so that the text and pdf remain stable.]
By 2030, there will be an estimated 2.4 trillion USD financial loss due to heat-related illness, even if we limit the rate of warming to 1.5°C above pre-industrial levels. Furthermore, by 2030, 80 million jobs will be lost due to high temperatures. [ Source]
I believe these facts merit at least their own paragraph because of the specific impact climate change will have on laborers' health in the workplace and therefore on the economy as a whole, as opposed to the broad-based health impacts on human health. Aem832 ( talk) 15:34, 22 May 2024 (UTC)