Joe Romm of Climate Progress had a post two weeks ago Trump falsely claims Paris deal has a minimal impact on warming

Romm states

In a speech from the White House Rose Garden filled with thorny lies and misleading statements, one pricks the most: Trump claimed that the Paris climate deal would only reduce future warming in 2100 by a mere 0.2°C. White House talking points further assert that “according to researchers at MIT, if all member nations met their obligations, the impact on the climate would be negligible… less than .2 degrees Celsius in 2100.”

The deeply prejudiced wording, written for an extremely partisan readership, encourages readers to accept the next part without question.

The 0.2°C estimate used by Trump may be from another MIT group; the Joint Program on the Science and Policy of Global Change did have such an estimate in early 2015, before all of the Paris pledges were in. But, their post-Paris 2016 analysis also concluded the impact of the full pledges was closer to 1°C.

The source for the 0.2°C claim is the MIT JOINT PROGRAM ON THE SCIENCE AND POLICY OF GLOBAL CHANGE. ENERGY & CLIMATE OUTLOOK PERSPECTIVES FROM 2015

This states

New in this edition of the Outlook are estimates of the impacts of post-2020 proposals from major countries that were submitted by mid-August 2015 for the UN Conference of Parties (COP21) meeting in Paris in December 2015.

So what INDC submissions were in by Mid-August? From the submissions page (and with the size of total 2010 GHG Emissions from the Country Briefs) we get the following major countries.

In box 4 of the outlook, it is only Korea that is not included in the 0.2°C impact estimate. That is just over half the global emissions are covered in the MIT analysis. But there were more countries who submitted after mid-August.

The major countries include

 
My table is not fully representative, as the UNFCCC did not include country briefs for Nigeria, Egypt, Saudi Arabia, Iran, Iraq, Kuwait and UAE. All these countries made INDC submissions along with a lot of more minor GHG emitters. I would suggest that by mid-August all the major countries that wanted to proclaim how virtuous they are in combating climate change were the early producers of the INDC submissions. Countries like the Gulf States, India and Indonesia tended to slip their documents in somewhat later with a lot of measly words to make it appear that they were proposing far more than token gestures and pleas for subsidies. Therefore, the 0.2°C estimate likely included two-thirds to three-quarters of all the real emission constraint proposals. So how does an analysis a few months later produce almost five times the impact on emissions?

The second paragraph of the page the later article Joe Romm links to clearly states difference in methodology between the two estimates.

A useful way to assess that impact is to simulate the effects of policies that extend the Agreement’s 188 pledges (known as Nationally Determined Contributions, or NDCs) to the end of the century. In a new study that takes this approach, a team of climate scientists and economists from the MIT Joint Program on the Science and Policy of Global Change led by research scientist Andrei Sokolov finds that by 2100, the Paris Agreement reduces the SAT considerably, but still exceeds the 2 C goal by about 1 C.

The primary difference is that the earlier study tries to measure the actual, real world, impacts of existing policy, and policy pledges, if those policies are fully enacted. In the USA, those pledges would need Congressional approval to be enacted. The later study takes these submissions, (which were only through to 2030) and tries to estimate the impact if they were extended until 2100.  That is renewables subsidies that push up domestic and business energy costs would be applied for 85 years rather than 15. It is not surprising that if you assume policy proposals are extended for over five times their original period, that they will produce almost five times the original impact. To understand this all that is required is to actually read and comprehend what is written. But Joe Romm is so full of bile for his President and so mad-crazy to save the planet from the evils of Climate Change and (mostly US) big business that he is blinded to that simple reality-check.

The fuller story is that even if all policies were fully enacted and extended to 2100, the impact on emissions would be far smaller than Joe Romm claims. That will be the subject of the next post.

Kevin Marshall