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Factcheck: Is 3-5C of Arctic heating now i locked in ’?



A new environmental report of 1965 was issued on the Arctic, covering a wide range of changes in the region's climate, environment, wildlife and epidemiology.

Press Release focused on the report on climate change. He warned, “even if the Paris Agreement targets the Arctic winter temperatures increase by 3-5C by 2050 compared to 1986-2005 levels” and reach 5-9C by 2080.

covered by several news outlets, including Guardian Wired CBC and other [1

9659002]. Media coverage focused on the idea – promoted in the press release – that large amounts of Arctic heating are “locked”, “inevitable” or “unavoidable”.

However, an investigation by Carbon Carbon found that the portion of a report on climate change is erroneously entered into the Paris Agreement goal – to limit its heating to “well below” 2C by the end of the century compared to pre-industrial levels – with a situation where emissions of approximately 3C of global warming result in a much more moderate emission

For a climate model using a case that limits heating global to less than 2C, the Arctic is still warmer than the rest of the world. But the Arctic winter warming will be about 0.5-5C by the 2080s compared to 1986-2005 levels, much lower than the 5-9C values ​​mentioned in the report.

This means that much of the future warming in the Arctic depends on our emissions over the 21st century, rather than being “locked”, as the report requires.

Error item

The title “Global combinations: Graphic observation of the Arctic is variable”. It provides a brief, accessible and infra-red view of a number of areas where the Arctic has changed in recent years and may change in the future.

The portion of the report covering Arctic temperatures – which is only two pages long – does not present any new research. Instead, it summarizes the results of some recent, more technical studies. The future temperature projections, which were the focus of the press release and related media coverage, are contained in one section of the report:

“Warmer temperatures in the Arctic have always been the highest. in winter sea between 2015 –2018 ( Overland et al., 2018 ). Indeed, under a medium emission or high emission scenario, predicted temperature changes for the Arctic winter heating trend will continue to be at least double the rate for the northern hemisphere (2017 AMAP). This means that even if countries are successful in cutting GHG emissions on the targets set out in the Paris 2015 Agreement on climate change, winter temperatures in the Arctic will be 3 to 5C higher by 2050 and 5 to 9C higher by 2080, In comparison with 1986– Levels 2005. Indeed, even if we stopped all emissions overnight, the Arctic winter temperature will still increase by 4 to 5C compared to the end of the twentieth century. This increase is locked into the climate system by already emitted GHGs and ocean heat storage (2017 AMAP). ”

However, there are some obscure statements and errors in this paragraph that make the message that there is a great Arctic warming in the future“

While the first two sentences are accurate, problems begin in third place when the report that Arctic heating would continue 3-5C in winter by 2050 and 5-9C by achieving the targets of the Paris Agreement. 2080, compared to 1986-2005 levels.

The reference to these numbers is the 2017 Monitoring and Evaluation Program (AMAP) report . The AMAP 2017 report states that:

“Over the Arctic Ocean, free from early winter ice in a number of models and covered by thin sea ice in the late winter, heating is 3–5C by the middle of the century and 5–9C by end of RCP4.5. "

The United Nations Environment report drops the reference to the Arctic Ocean, referring to these warming projections as" winter temperatures in the Arctic "- the Earth's area much larger than the region above the Arctic Ocean. . Actual heating in RCP4.5 for the entire Arctic (between 60N and 90N) in the 2017 AMAP report is slightly lower: around 3.8-7.8C in the 2080s. There is another small issue where the new report gives specific years (2050 and 2080), and the 2017 AMAP report uses the periods from 2050-2059 and 2080-2089.

Glossary

RCP4.5: The RCPs (Concentration Representative Corridors) are cases for future greenhouse gas concentrations and other seizures. RCP4.5 is a “stability case” that puts policies in place to ensure atmospheric CO2 concentration levels… Read More

The problem arises when it combines AMAP heating numbers 2017 – refers to the RCP4.5 case – “the targets set out in the Paris 2015 Agreement on climate change”.

In the Paris Agreement, countries set a target to limit “well below” 2C heating, to limit an ambitious target of under 1.5C heating. However, the AMAP report 2017 only considers two future emissions scenarios: RCP8.5 very high emission scenario, where the world suffers more than 4C heating; and RCP4.5 medium-emission case, where the world's 3C warming compared to pre-industrial levels by the end of the century.

Glossary

RCP2.6: The RCPs (Concentration Representative Corridors) are cases for future greenhouse gas concentrations and other seizures. RCP2.6 (also referred to as “RCP3-PD”) is a “peak and deterioration” scenario where there is a…… More Read More

If countries were meeting the Paris Agreement limiting heating to “under enough” 2C, global emissions of RCP2.6 case (or reducing emissions would accelerate to limit heating to 1.5C). While RCP2.6 still sees additional Arctic heating, it is significantly less than the numbers in the report.

The figure below shows the winter warming in the Arctic from the climate models CMIP5 used in the fifth assessment report of the Intergovernmental Panel on Climate Change (IPCC) in the case of RCP2. 6. The average black lines show all the models, the dark area shows the range of two-thirds of the models (the range [sigma ), and the light area shows the range covering 95% of the model (runs). the two-sigma range ).

The RCP2.6 climate model from CMIP5 runs for the region between 60N and 90N for the winter months (December, January and February) for the 32 different climate models provided by RCP2.6 bikes (with one run per model). ). Exemplar data obtained from KNMI Climate Explorer

Where the Paris Agreement target is met, actual winter warming projected for the Arctic in the 2050s and 0.5-5C in the 2080s is 0.8-4.5C compared to 1986–2005 levels ( following the approach used in the 2017 AMAP report on the provision of one-sigma ranges). The multi-model consists of heating 2.8C in the 2050s and 2080s, as more global emissions limit warming after the middle of the century.

The statement in the report “even if all emissions are stopped overnight, winter temperatures will increase by 4C to 5C on the Arctic still compared to the end of the twentieth century” it is crazy, as it is not seen in place. The 2017 AMAP report states that it states.

There is confusion, claiming that emission cuts are being compiled by the United Nations Environment report. there would be more heating in zero immediately than in climate models running the RCP2.6 case – a case that has reached zero emissions at around 2080 . A Carbon Brief came to a number of climate scientists, all of whom made a dangerous statement about what could be the cause of this claim. The United Nations Carbon on the Environment Directive and the authors of the report requested a reply, but did not receive one before it was published. (This article will be updated to include any response.)

According to an analysis was in the IPCC's special report on 1.5C decreasing the all greenhouse gas emissions and as a result of immediate aerosols, there would be a modest modest lump in global temperatures of around 0.15C as the Earth's cooling aerosols disappear, followed by a decline. Around 20 years after zero emissions, global temperatures would fall below today's levels and then they would receive around 0.25C by 2100. While aerosol could have a greater impact on the Arctic than other regions, it seems unlikely that there will be additional long-term heating of 4C to 5C [

Not locked

Why the report could blend a 3C global warming case (RCP4.5) with the Paris Agreement target (RCP2.6)? The actual commitments made by countries in the Paris Agreement – the well-settled contributions (NDCs) – of fall out of what would be needed to fulfill Paris's goal. Unless countries undertake these activities only – and they do not draft their promises after the Paris commitment period of 2030 has been abolished – studies suggest that the world would be on the road for slightly more than 3C warming [19659002] while the greatest amount depends on assumptions relating to emissions between 2030 and 2100.

However, even if the report was concerned “the warming implicit by existing Paris commitments ”rather than the Paris targets”, the press release and media coverage remains misleading. If the authors are not arguing that the whole world is already locked in 3C heating – and there are many cases that would cause global warming below 2C, or even to 1.5C warming – the size of future warming in the Arctic during the 21st century will depend heavily on our future emissions

The figure below shows the winter Arctic warming compared to 1986-2005 from all the IPCC climate models CMIP5 for all all future RCP emission case. There is a wide range of potential future heating, from as little as 2.7C in 2100 in RCP2.6 to as much as 12C in RCP8.5. Any of these future heating scenarios depends on our greenhouse gas emissions in the rest of the 21st century.

CMIP5 Multimoder mode for each RCP case for the region between 60N and 90N in the winter months (December, January and February)). Exemplar data received from KNMI Climate Explorer

If the world meets the Paris target of limiting heating 2C, the Arctic winter warming will be about 0.5-5C, much lower than the 5-9C values ​​mentioned in the report. t

There is still a wide range of potential results for the region. As a result, there is no claim that huge amounts of future warming are locked.

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