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Global warming

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I've listed this article for peer review because it is a popular page on an important yet controversial topic and it has been updated and rewritten significantly over the last twelve months. While I hope the entire article can be vetted, I feel least confident about the quality of the lede section and the mitigation subsection.

Thanks, Femke Nijsse (talk) 20:29, 14 February 2020 (UTC)[reply]

JoJo Eumerus

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Some thoughts:

  • Perhaps I've been too immersed in "so it's a boy or a girl?" debates, but is there consensus on the lead temperature map?
  • As the lede image is an average over a relatively long period, I don't think ENSO is observable much. I proposed we find a figure that averages over a longer period (2010-2019) to dispell the notion that some areas have cooled over the longterm. Couldn't find a good image then, I could have a further look/make one myself. Femke Nijsse (talk) 18:11, 17 February 2020 (UTC)[reply]
With that source I made the following image. Any suggestions for improvements before I upload? Femke Nijsse (talk) 21:45, 26 February 2020 (UTC)[reply]
Map global warming 2010-2019
 Done Femke Nijsse (talk) 19:37, 29 February 2020 (UTC)[reply]
  • Is it necessary to have all these references in the lead?
It's a really big article so I recommend keeping them   User:Dunkleosteus77 |push to talk  00:37, 17 February 2020 (UTC)[reply]
With a highly contentious topic, I find it desirable to have a fully cited lede. I deleted one unnecessary cite that was impeding readability because it was mid-sentence. Will look at the last sentence, which has another three mid-sentence cites. Femke Nijsse (talk) 18:11, 17 February 2020 (UTC)[reply]
 Not done Femke Nijsse (talk) 19:37, 29 February 2020 (UTC)[reply]
  • Is the "mitigation" section meant to discuss only their (in)effectiveness?
  • I don't quite understand your comment. I think the mitigation section should cover the major options in term of technology and policy. To put both into context, I also put in some background material. There is further background material in the Causes section, and actual policy information in the 'Political response' subsection. I'm not completely confident of the split of information between these three places. Femke Nijsse (talk) 18:11, 17 February 2020 (UTC)[reply]
What I meant is that is that 3/4 of the section is about their ineffectiveness and only 1/4 about actual measures. JoJo Eumerus mobile (main talk) 12:21, 19 February 2020 (UTC)[reply]
You believe more should be written about concrete technologies, instead of policies? Or/and do you think the background information in the subsubsection of 'Drivers of greenhouse gas emissions' should be summarized/omitted/moved? I'm struggling quite a bit with the latter. It could be placed under drivers, but then we'd have to many figures (that I deem essential) there. The second paragraph under that heading (Emission scenarios ...) could be placed in the model and projection section's third paragraph. It could be placed in the model&projections section.. Femke Nijsse (talk) 18:34, 19 February 2020 (UTC)[reply]
I've removed one sentence from 'drivers of GHG emissions' and expanded on energy technologies. Do you think that is the right direction? Femke Nijsse (talk) 18:34, 19 February 2020 (UTC)[reply]
Yes. What I am thinking is that some discussion of the concrete steps taken might be warranted ... although I see some of them are discussed several sections farther down. Jo-Jo Eumerus (talk) 20:20, 19 February 2020 (UTC)[reply]
 Done (taking it further from Hedgehoque's comments). Femke Nijsse (talk) 19:37, 29 February 2020 (UTC)[reply]
Don't really understand "Planetary boundaries – climate change is one of them"   User:Dunkleosteus77 |push to talk  17:13, 18 February 2020 (UTC)[reply]
Yes, that one sounds unclear to me as well. JoJo Eumerus mobile (main talk) 12:21, 19 February 2020 (UTC)[reply]
 Done? How does the following sound: nine environmental boundaries that define a safe operating space for humans; climate change is one of them? Femke Nijsse (talk) 11:55, 1 March 2020 (UTC)[reply]
"environmental boundaries " is a little unclear to me still. Jo-Jo Eumerus (talk) 12:04, 1 March 2020 (UTC)[reply]

Dunkleosteus77

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  • The reason italics was used there, is that these sentences describe the words per MOS:WORDSASWORDS. Your comment indicates that we might not have succeeded here. We could possibly remove the sentence "Global warming and climate change are often used interchangeably", and start the next sentence with Specifically, (...). Then there would be no more use for italics. Do you think this much emphasis on the technical difference between the two terms is warranted as the second and third sentence? Femke Nijsse (talk) 18:18, 17 February 2020 (UTC)[reply]
You can also use quotation marks instead of italics   User:Dunkleosteus77 |push to talk  17:10, 18 February 2020 (UTC)[reply]
Quotations marks will surely be the wrong option here, right? They could be interpreted as scare quotes. It also doesn't fall in any of the categories in Wikipedia:Manual_of_Style#Words_as_words for using quotations... What do you think of the fact we use two sentences for the distinction between the two terms? Femke Nijsse (talk) 18:09, 18 February 2020 (UTC)[reply]
That’s good too, just giving you options   User:Dunkleosteus77 |push to talk  19:02, 18 February 2020 (UTC)[reply]
why is "external forcings" italicized?   User:Dunkleosteus77 |push to talk  16:45, 23 February 2020 (UTC)[reply]
 Done I rewrote the first paragraph quite extensively. Let's see to what extend it sticks. Femke Nijsse (talk) 20:42, 25 March 2020 (UTC)[reply]
 Done. I've replaced it with The observed rise in temperature and CO2 concentrations have been so rapid that even abrupt geophysical events do not approach current rates., which fits better in the context. I've moved the previous sources to the effects sections, stating directly we know about these effects from past climate change. Femke Nijsse (talk) 15:41, 15 March 2020 (UTC)[reply]
 Done Femke Nijsse (talk) 17:58, 25 March 2020 (UTC)[reply]
The first time you mention it in the body of the article you should spell it out entirely   User:Dunkleosteus77 |push to talk  17:10, 18 February 2020 (UTC)[reply]
 Done Femke Nijsse (talk) 17:58, 25 March 2020 (UTC)[reply]
It doesn't seem entirely important because in total the ocean is warming up   User:Dunkleosteus77 |push to talk  03:51, 20 February 2020 (UTC)[reply]
This is an explanation why the oceans' temperature is going up slower than land, so yes this does matter. Even in equilibrium I think there will be a difference in temperature. Will think about wording more. Femke Nijsse (talk) 17:58, 25 March 2020 (UTC)[reply]
  • "has resulted in the maximum surface area flipping from reflective snow and ice cover to ocean and land surfaces that absorb more sunlight and thus more heat." don't really understand, still left thinking if the Southern Hemisphere has more ocean, and the ocean has a very low albedo, shouldn't the Southern Hemisphere be warming up faster?   User:Dunkleosteus77 |push to talk  00:37, 17 February 2020 (UTC)[reply]
    That sentence was indeed quite ugly. They key point here is that a region will warm faster if there is a change is albedo. The SH was already quite dark in summer, so there are no large self re-inforcing feedbacks.
    New sentence better: The Northern Hemisphere not only has much more land, but also more snow area and sea ice, because of how the land masses are arranged around the Arctic Ocean. As these surfaces flip from being reflective to dark after the ice has melted, they start absorbing more heat. The Southern Hemisphere already had little sea ice in summer before it started warming.
I still don't like it, my brain is reading it but it isn't really processing anything (it's too confusing/disorderly). Use "Because the albedo of the Northern Hemisphere is changing much more rapidly than that of the Southern Hemisphere due to a greater loss of reflective snow and ice cover, it is warming up faster."   User:Dunkleosteus77 |push to talk  03:49, 20 February 2020 (UTC)[reply]
 Done Removed throughout the article. Femke Nijsse (talk) 19:23, 23 February 2020 (UTC)[reply]
 Half done I've rewritten. I expect it should be clearer now, but not yet good enough. Could you have another peek?
The section is about observed ánd projected changes, so this wouldn't be correct. Femke Nijsse (talk) 19:23, 23 February 2020 (UTC)[reply]
Then you should reorganize the article so there’s a section on observed changes and another on projected changes   User:Dunkleosteus77 |push to talk  21:57, 23 February 2020 (UTC)[reply]
I believe that would be quite horrible to be honest. You'd get a section with we observe more insense storms, sea level rise (SLR), heat waves. And then further in the article: we expect more intense storms, more SLR and heat waves. That is repetitive. Furthermore, taking away the context of what has already been observed rips away the context for future predictions. Statements about predictions are usually supported scientifically by what we have seen so far, and I believe we should follow those sources. Femke Nijsse (talk) 22:21, 23 February 2020 (UTC)[reply]
Then by that logic, delete the Observed temperature rise section for being repetitive   User:Dunkleosteus77 |push to talk  23:08, 23 February 2020 (UTC)[reply]
 Not done I think we discussed this half a year ago or something. As this article is about warming, I believe it's justified to spread out observed warming, causes of warming and future warming into three different sections. One section would become too big. Femke Nijsse (talk) 19:53, 15 March 2020 (UTC)[reply]

Chidgk1

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  • As a 3 degree rise in temperature seems quite likely, how likely is it that it would cause a self reinforcing feedback? I could not see the answer from a quick scan of Tipping points in the climate system. Is the question important enough to be answered in this article or should it be relegated to that one? In other words is the likelihood more than, say 10%? And is the likelihood greater than 10% at 2 degrees? Chidgk1 (talk) 18:24, 20 February 2020 (UTC)[reply]
Self-reinforcing feedbacks are always active, even in the absence of tipping points. I've made that more clear in the lede of climate sensitivity, and I think this should be covered in the tipping points article better as well. The 'global warming' article now contains the following (awkward) sentence: A concern is that self-reinforcing feedbacks will lead to a tipping point, where global temperatures transition to a hothouse climate state even if greenhouse gas emissions are reduced or eliminated.. The likelihood of these tipping points, which are either carbon-cycle based or cloud-based, is very difficult to determine. Even before tipping, these things create positive feedbacks to warming. I'll rewrite the sentence I just mentioned, and the paragraph about tipping points under the effects heading. Femke Nijsse (talk) 20:22, 22 February 2020 (UTC)[reply]
I've rewritten both mentions of tipping points/feedbacks in the article. Is it clearer now? Did I add any awkward English that needs correcting? Femke Nijsse (talk) 11:05, 23 February 2020 (UTC)[reply]
Thanks. I probably need to read the tipping points article properly and then read here again. Meanwhile "a strong tipping points in cloud cover" should be either singular or plural.Chidgk1 (talk) 17:14, 26 February 2020 (UTC)[reply]

Hedgehoque

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Some of you may have noticed that I already tried to restructure the responses section, focussing on the mitigation part. The edit was reverted, just like the first attempt. Nevertheless, please let me try to explain the suggestions step by step, including some new ideas: Numbering by Femkemilene to make it easier to respond. Reducing greenhouse gases

1. Move: "There is a large potential for reductions in emissions, mainly by reducing fossil fuel use and better regulating fossil fuel companies" - The regulating part appears to be too prominent to me, here. The Guardian article is about undocumented methane blowouts. This is serious but also speculative. This aspect could appear later on.

(hope I am supposed to respond here - it not I can move to my own section) I am against removing this sentence completely as reducing fossil fuel use is the key point I think. Possibly it could be amended or split as whether better regulation of fossil fuel companies is also very important I am not sure and would be interested to hear other opinions.Chidgk1 (talk) 17:47, 26 February 2020 (UTC)[reply]
I agree that regulating fossil fuels has too prominent a location there. Not removed it yet as I couldn't find a good source to replace the Guardian article. If you find one, feel free to add! Femke Nijsse (talk) 20:15, 29 February 2020 (UTC)[reply]
 Done not sure when, but it seems I (/somebody?) deleted it in the end. Femke Nijsse (talk) 17:24, 22 March 2020 (UTC)[reply]

2. This is the part I would like to add about renewable energy - once again shortened. The role of RE is central in the whole context. Here comes global energy transition in a nutshell:

Levelized costs of wind energy and solar photovoltaics are increasingly out-competing fossil fuels[1] but require energy storage or low-loss[2] power superhighways for a continous supply in a 100% sustainable scenario. Installation of wind energy, solar photovoltaics, concentrated solar power and hydroelectricity would have to be accellerated six-fold though to stay under the 2 °C target.[3] Many countries have introduced a carbon tax or the closely related emissions trading[4] to speed up that process. Competitive storage concepts include hydrogen, pumped hydro, compressed air and batteries.[5]
The article has to be understable for a sufficiently broad public. I think this suggestion suffers from quite a few difficult concepts, that are probably too detailed for this article. The word levelized is too difficult, as well as photovoltaics (people just call it solar energy or PV). I recently spoke to an energy transition expert, who indicated that IRENA often pushes researchers towards certain conclusions in their commissioned work, so I'm reluctant to use any of their numbers in this article. The clause "to speed up that process" is not sourced and not the whole reason. Carbon taxes and the like do a whole set of things: coal-to-gas switching, energy efficiency & conservation, NET, energy storage. The main goal is to reduce carbon emission by the cheapest means possible. With these problems, I won't copy paste this contribution, but will further look at which points to integrate later. Femke Nijsse (talk) 18:36, 27 February 2020 (UTC)[reply]
Ok about levelized costs - the sentence also works without them. About IRENA: Add According to..? Of course, they have a mission. But their estimation is plausible. According to the BP statitics (p.9), RE and hydro produiction grew by about 100 Mtoe in 2018. The global primary energy demand is almost 13,865 Mtoe per year including 1,500 Mtoe RE/Hydro already produced. With a six-fold accelleration you can get there in about 20 years (600 x 20 = 12,000) - though I admit that this is a very rough calculation. Energy demand will probably grow while at the same time efficiency increses (with grids, not so much with storage). I agree with your comment on the "speed-up" clause.Hedgehoque (talk) 07:37, 28 February 2020 (UTC)[reply]
checkY the grids are now inserted into the text. I'm still not keen on a specific number, especially since it's a bit vague. Does the total need to scale up or each individual technology? Surely, hydro doesn't have that much growth potential anymore. Again, feel free to do small edits, which I'll try to work on and improve. Femke Nijsse (talk) 17:17, 24 March 2020 (UTC)[reply]

3. The potential of large installations of photovoltaics/wind energy in remote areas in combination with a global supergrid of power lines could even be more emphasized . RS pointing into that direction: North American Supergrid study, the submarine power cable from Europe to North America, the China-EU transmission link by the EC Joint Research Center and the Chinese Global Energy Interconnection initiative.

 Done By Hedgehoque

4. Remove: "Co-benefits of climate change mitigation may help society and individuals more quickly. For example, cycling reduces greenhouse gas emissions while reducing the effects of a sedentary lifestyle at the same time." - I'd rate it a real side-aspect though I like cycling.

Yes I agree. Correct me if I am wrong (maybe I am contradicting the IPCC definition of "measures to mitigate the atmospheric concentration of warming climate-altering pollutants that also hold the potential to significantly benefit human health") but I think the largest benefit is not a co-benefit. For example for cycling health is the benefit and climate change mitigation is a co-benefit not the other way round. Similarly when shutting down an old coal-fired power station near a city health is the main benefit and climate change mitigation is a co-benefit. However in the politics section there could be mention of short-term health benefits making it easier for politicians to introduce laws which have climate change co-benefits - low-emission zones for example. Chidgk1 (talk) 17:47, 26 February 2020 (UTC)[reply]
 Not done I don't mind having a smaller example in the text, but feel free to replace it with the more substantial one of coal and air pollution. As this is a section about climate mitigation, I'd say that per definition any other thing (even if it's 'more important' is a co-benefit. (It seems Chidgk1 is doing that at this moment even!) Femke Nijsse (talk) 17:17, 24 March 2020 (UTC)[reply]

5. The Drivers of greenhouse gases section is important to understand mitigation approches. But this is not a response. Should we place it as an own caption before the responses section?

checkY I've removed the subsubsection and split the mitigation subsection differently. It was confusing before. The drivers are now described in causes, modelling and introductory paragraph mitigation. Femke Nijsse (talk) 16:50, 8 March 2020 (UTC)[reply]

6. Add: Fossil fuels in electricity, transport and the heat sector count for more than 70% of greenhouse gas emissions [6] - I would like to start with this fact in the drivers section. It is the main issue.

checkY I've removed that entire subsubsection, but the information is present (in slightly different form) in the causes section.

7. Remove: "Emissions scenarios, estimates of changes in future emission levels of greenhouse gases, depend upon uncertain economic, sociological, technological, and natural developments. In some scenarios emissions continue to rise over the century, while others have reduced emissions." - It is self-evident that noone can predict the future. In doubt this can be moved to models and projections. This does not answer the question who the drivers are.

checkY I've moved it to models and projections section. I think it serves a purpose in the sense that it's clear all these things are modelled and us silly climate scientists don't forget about those. Femke Nijsse (talk) 20:07, 15 March 2020 (UTC)[reply]

8. "Emission scenarios can be combined with modelling of the carbon cycle to predict how atmospheric concentrations of greenhouse gases might change in the future. According to these combined models, by 2100 the atmospheric concentration of CO2 could be as low as 380 or as high as 1400 ppm, depending on the Shared Socioeconomic Pathway (SSP) the world takes and the mitigation scenario." - Same here. Remove or move to models and projections.

checkY Same

9. Maybe add a sentence about methane emissions in meat production which count for a notable share of GHG equivalents in agriculture (RS yet to be found)?

 Done It was already mentioned in mitigation and scientific opinion, but now also in causes. Femke Nijsse (talk) 20:52, 25 March 2020 (UTC)[reply]

Mitigation lead

10. Move: Near- and long-term trends in the global energy system are inconsistent with limiting global warming to below 1.5 or 2 °C relative to pre-industrial levels. Current pledges made as part of the Paris Agreement would lead to about 3 °C of warming at the end of the 21st century, relative to pre-industrial levels. To keep warming below 2 °C, more stringent emission reductions in the near-term would allow for less rapid reductions after 2030. To keep warming under 1.5 °C, a far-reaching system change on an unprecedented scale is necessary in energy, land, cities, transport, buildings, and industry. - Could we move this to the policy section?

 Not done I removed one of the sentences, which was a bit self-evident. I think both locations work for this sentence, but I prefer to keep scientific analysis in the mitigation section, as political negociation in the other section. I won't revert if you move, but make sure to switch around the figure of Paris for the on on energy use. Femke Nijsse (talk) 17:17, 24 March 2020 (UTC)[reply]

Adaption

11. Move: In June 2019, U.N. special rapporteur Philip Alston warned of a "climate apartheid" situation developing, where global warming "could push more than 120 million more people into poverty by 2030 and will have the most severe impact in poor countries, regions, and the places poor people live and work" - Move to Effects/Humans ?

 Done. Do you think it should be included at all? Femke Nijsse (talk) 18:44, 1 March 2020 (UTC)[reply]

Geopolitical implications

12. A new subsection under mitigation or politics could raise awareness why this topic is so controversial. The Citibank study and most vulnerable countries from the existing article are also included in this draft:

In 2019, oil and gas companies were listed with sales of about 5 % of the global gross domestic product.[7]. Net importers such as China and the EU would gain advantages from a transition to low-carbon technologies while others would see their fossil fuel industries shut down.[8]. A 2015 report by Citibank concluded that transitioning to a low-carbon economy would yield a positive return on investments.[9] The production of renewable energy technologies requires Rare-earth elements with new supply chains.[10] Many of the countries that have contributed least to global greenhouse gas emissions are among the most vulnerable to climate change, which raises questions about justice and fairness with regard to mitigation and adaptation.[11]

Hedgehoque (talk) 00:32, 26 February 2020 (UTC)[reply]

I've added the Mercure study a bit more extensively than you did, as I believe their analysis of prisoner's dillemma is extremely important. I don't think that all these sources are directly geopolitics. For instance, the listing of the percentage fossil fuel is probably relevant, but the source you gave me didn't mention climate change directly. I haven't yet had time to look deeply into the renewable energy geopolitics source you linked, but I will surely read it. Femke Nijsse (talk) 20:54, 9 March 2020 (UTC)[reply]
checkY Also added the renewables. Not sure if it's sufficiently important to be included, but will become more important in the next coming years. Femke Nijsse (talk) 17:17, 24 March 2020 (UTC)[reply]

Thank you, @Femke: Much work for you and the whole article looks better now! Please let me add three more remarks:

1. The Pitbull link appears like well-paced PR on top of this FA. I think we could simply remove it. Anyone looking for the album would check the discography. A disambiguation page would not be neccessary.

 Done I think we have to link to the disambiguation page, but not directly to the album. Femke Nijsse (talk) 13:25, 22 March 2020 (UTC)[reply]

2. In the current version, energy storage is not mentioned at all. It is a big issue and an important part of the solution. Should I add?

 Done Thanks for adding. I've made the cite conformant with the strict referencing we use for this article. Femke Nijsse (talk) 13:25, 22 March 2020 (UTC)[reply]

3. The discussion is dominated by projections that end in 2100 - just like the article. We could add a study by the Potsdam Institute: For each degree of warming above pre-industrial, sea level will rise by about 2.3 m within a period of 2000 years. [12] More stuff worth reading about this: UNU Ourworld: What happens after 2100 and Nature: What happens after global warming with graphs that illustrate weathering effects over the next 100,000 years.Hedgehoque (talk) 22:15, 17 March 2020 (UTC)[reply]

The current paragraph about about long-term effects (part of physical effects) has a bit of a strange focus on geological effects (tsunamis, seismic activity). I'll rewrite it focusing more on ocean acidification, sea level rise and maybe mroe. Bear with me. Femke Nijsse (talk) 13:25, 22 March 2020 (UTC)[reply]
 Done Femke Nijsse (talk) 17:24, 22 March 2020 (UTC)[reply]

References

  1. ^ "Levelized Cost of Energy Analysis (LCOE 13.0) and Storage Analysis (5.0)". Lazard. Retrieved 31 January 2020.
  2. ^ "UHV Grid". Global Energy Interconnection (GEIDCO). Retrieved 26 January 2020.
  3. ^ "Global Energy Transformation: A Roadmap to 2050 (2019 edition)" (PDF). IRENA. Retrieved 29 January 2020.
  4. ^ Hagmann, Ho & Loewenstein 2019
  5. ^ "Projecting the Future Levelized Cost of Electricity Storage Technologies". CellPress. Retrieved 31 January 2020.
  6. ^ "GHG Emissions". CAIT Climate Data Explorer. Retrieved 29 January 2020.
  7. ^ "Oil and gas companies earn most revenue in Forbes 2019 largest firms list". NS Energy. Retrieved 3 February 2020.
  8. ^ "Macroeconomic impact of stranded fossil fuel assets (Abstract)". Nature Climate Change. Retrieved 26 January 2020.
  9. ^ The Guardian, 31 August 2015.
  10. ^ "The Geopolitics Of Renewable Energy" (PDF). Center on Global Energy Policy Columbia University SIPA / Belfer Center for Science and International Affairs Harvard Kennedy School. Retrieved 26 January 2020.
  11. ^ IPCC AR5 SYR Summary for Policymakers 2014, p. 17, Section 3.
  12. ^ "Sea Level Changes". Potsdam Institute. Retrieved 17 March 2020.

Dtetta

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Proposed revisions to lead paragraphs

The ending clause in the last sentence of the first paragraph needs revision. It appears to be pulled directly from the IPCC SPM report that it references, and in the context of the overall sentence I don’t understand what it means as written. I suggest changing it from “many observed changes since the mid-20th century have been unprecedented over decades to millennia” to either ”the changes observed since the mid-20th-century are unprecedented in recent millennia”, or just eliminate the words “decades to millennia”. checkY

I think there must be highly reliable sources that have a stronger statement than the IPCC. In their absence, I'm not keen to change this prominent (awkward) sentence at all. It would be a massive help if you could find a more recent source of a similar caliber that has a slightly stronger statement. Femke Nijsse (talk) 10:59, 1 March 2020 (UTC)[reply]
And the IPCC's more recent report indeed has way stronger wording. Has been adjusted. Femke Nijsse (talk) 15:11, 1 March 2020 (UTC)[reply]

Thanks, I like the way you edited it.Dtetta (talk) 21:06, 1 March 2020 (UTC)[reply]

Although the addition of the reference to the 1.5°C IPCC recommendation is a helpful addition to the second paragraph, the logical flow now seems a bit disjointed. There is also some duplication and inconsistency with the 2°C reference in the fourth paragraph (I realize the IPCC report mentions both the 1.5°C and 2°C end points, but I think it best to stick with just one for the lede. I would propose the following edits to the second paragraph, with proposed added text in underline and deleted text in strikeout; text in italics is included at times to provide an explanation for changes.

The Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report concluded, "It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century”. The largest human influence has been the emission of greenhouse gases such as carbon dioxide, methane, and nitrous oxide, with agricultural emissions and deforestation also playing significant roles.checkY Added to make the paragraph more consistent with the global warming and climate change infographic.These findings have been recognized by the national science academies of the major industrialized nations and are not disputed by any scientific body of national or international standing. The IPCC has stressed the need to keep global warming below 1.5 °C compared to pre-industrial levels in ordercheckY to avoid irreversible impacts. The Earth's average surface temperature has already increased by about two thirds of this threshold and current pledges by countries to cut emissions are inadequate to limit future warming. At the current greenhouse gas (GHG) emission rate of 42 gigatons (Gt) per year, the carbon budget for staying below 1.5°C will be exhausted by 2028. Even Wwith current policies and pledges, global warming by the end of the century is expected to be around 3 °C.(just over 2 °C to 4 °C, depending on climate sensitivity). The IPCC has stressed the need to keep global warming below 1.5 °C compared to pre-industrial levels to avoid irreversible impacts. The remaining carbon budget for staying below 1.5°C with a twothirds chance would be exhausted in 2028 if emissions remained on the current level of 42 GtCO2 per year.checkY

The following are proposed edits to the third and fourth paragraphs.

The effects of global warming include rising sea levels, regional changes in precipitation, more frequent extreme weather events such as heat waves, the retreat of glaciers,Red XN and expansion of deserts. Ocean acidification is also caused by greenhouse gas emissions and is commonly grouped with these effects even though it is not driven by temperature.checkY Surface temperature increases are greatest in the Arctic, which have contributed to the retreat of glaciers, permafrost, and sea ice. Overall, higher temperatures bring more rain and snowfall, but for some regions droughts and wildfires increase instead. Climate change threatens to diminish crop yields, harming food security, and rising sea levels may flood coastal infrastructure and force the abandonment of many coastal cities.Environmental impacts include the extinction or relocation of many species as their ecosystems change, most immediately in coral reefs, mountains, and the Arctic. Some impacts, such as loss of snow/ice cover, increased water vapor, and melting permafrost, cause feedback effects that further increase the rate of global warming. checkY Ocean acidification is also caused by greenhouse gas emissions and is commonly grouped with these effects even though it is not driven by temperature.checkY Sentence moved the the end of the paragraph, as it has more of a parenthetical purpose within the general paragraph context, proposed additions are done to make paragraph consistent with changes described in infographic.

Mitigation efforts to address these global warming impactsSocietal responses to global warming include mitigation by emissions reduction, the development of low carb energy technologies, policies to reduce fossil fuel emissions, enhancement of existing carbon sinks via reforestation, forest preservation, and further development of regenerative agriculture, as well as the development of potential climate engineering technologies. adaptation to its effects, and possibly climate engineering. Societies and governments are also working to develop adaptation responses to current and future global warming impacts, including improved coastline protection, improved land use and insurance policy practices in sensitive areas, better disaster management, and the development of more resistant crops.checkY Countries work together on climate change under the umbrella of the United Nations Framework Convention on Climate Change (UNFCCC), which entered into force in 1994 and has near-universal membership. The ultimate goal of the convention is to "prevent dangerous anthropogenic interference with the climate system". Although the parties to the UNFCCC have agreed that deep cuts in emissions are required and that global warming should be limited to well below 2 °C (3.6 °F) in the Paris Agreement of 2016, the Earth's average surface temperature has already increased by about half this threshold and current pledges by countries to cut emissions are inadequate to limit future warming. checkY The second half of this sentence was moved to the second paragraph to reinforce the statements there, the first half is somewhat confusing in light of the 1.5 statement in the second paragraph, so I recommend deleting.Dtetta (talk) 16:23, 29 February 2020 (UTC)[reply]

Wow, thanks. With your knowledge about the topic and language skills, we're definitely able to improve the lede. With my computer dying, I'm not sure how fast I can respond. I'll put a checkY if I copy something word-by-word, a checkY if I've done something in your desired direction and I'll give explanation if I don't agree. Femke Nijsse (talk) 19:34, 29 February 2020 (UTC)[reply]
I think I will implement some of the proposed edits for the second paragraph. The addition about agriculture is comparing apples and pears: You can either say: emissions are from industry, energy and agriculture, and/or emissions are CO2, methane and N2O. You shouldn't mix up the two categories.
Your further text is better English, but it leaves out important information about confidence. From a risk perspective, saying that we'll have around 3 degrees of warming without noting the large range of possible temperatures gives an illusion of relative safety, as a 4 degree world is almost inconceivably different from our current world, whereas three is still sorta doable. What do you think of omitting the three and simply saying: between about 2 and 4 degrees? Same for the carbon budget, and that sentence can easily be repaired by adding the word likely between 'will' and 'be exhausted'.

Glad you like the proposed edits. I agree with your thoughts on the second paragraph. I don’t know what I was thinking when I wrote the sentence combining types of GHGs with different sources (it was late at night), but that was clearly a botched edit attempt. I do think it would be helpful to list types of gases as well as categories of sources. So maybe a something like: “The largest human influence has been the emission of greenhouse gases such as carbon dioxide, methane, and nitrous oxide. Fossil fuel emissions are the dominant source of these gases, with agricultural emissions and deforestation impacts also playing significant roles.” would be a good approach, but I would leave that to your judgement. I also agree with your thoughts on how to characterize end-of-century temperature estimates. I think I was overly focused on having definitive language where possible, but clearly in this case a temperature range is more appropriate. It looks to me like the CAT tracker graph for 2100 [1] shows predictions for current policies ranging from 2.8 to 3.2°C, with the addition of pledges bringing the lower end down to 2.5. But again I would defer to your judgment on the best way to characterize that; I have no idea to what extent climate sensitivity is a factor in their estimates. And your suggestion on the carbon budget sentence makes sense to me as well. Dtetta (talk) 07:04, 1 March 2020 (UTC)[reply]

I agree about the fact that information about goals (Paris, 1.5, 2) is now weirdly spread over the second and fourth paragraph and that switching between the two goals is also confusing. I'd prefer adding all the information in the fourth paragraph, because these thresholds are intimitely linked to mitigation efforts. I prefer to keep Paris in the lede though. What was your reasoning to remove it except that it doesn't correspond with other information?
I have added some of the concrete examples you suggested, but I don't think we have space for all of them. I've tried to only add those that are easy to understand, so left out regenerative agriculture for instance.
The retreat of glaciers feels a bit more natural in the second sentence of the paragraph, but of course many glaciers have also retreated outside of the Arctic. Femke Nijsse (talk) 10:21, 1 March 2020 (UTC)[reply]
Climate sensitivity is what drives the range they give. Climate Twitter told me they incorporate the carbon cycle uncertainties though.
I'm done now replying to your comments. I'm sure my bold compromises can be further improved/I missed some of your suggestions. Femke Nijsse (talk) 10:59, 1 March 2020 (UTC)[reply]

Great job with those edits! I think those five lead paragraphs look really good:)Dtetta (talk) 14:37, 1 March 2020 (UTC)[reply]

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