The Trump Administration scored an own goal by its Cunning Plan to release the mandated National Climate Assessment on the Friday after US Thanksgiving, counting on comatose satiety to distract public attention. In fact, it was such a quiet news day, without outrageous Trump tweets, that the report’s dire warnings got unusual coverage.
The usual shills, rallied by the Leader himself, promptly decried the report as the usual alarmism.
For once, I have to say that the shills have half, or perhaps a quarter, of a point. The NCA makes the situation worse than it really is (which is bad enough). Here’s my take.
The issue lies in the use of a piece of professional jargon, the RCPs (Representative Concentration Pathways). These were defined ten years ago in 2008-2009 by the climate science community to provide benchmarks for comparing different climate models, using a short list of different assumptions about future emissions. RCP 8.5 is the highest emission track, leading to at least 4 degrees C of warming by end century. The best, RCP 2.6, represents early peaking of emissions and the prospect of climate stabilisation.
It matters a great deal which we are on. The NCA says it’s RCP 8.5. Overview (pdf page 10), my emphasis:
The higher scenario (RCP 8.5) represents a future where annual greenhouse gas emissions increase significantly throughout the 21st century before leveling off by 2100, whereas the other RCPs represent more rapid and substantial mitigation by mid-century, with greater reductions thereafter. Current trends in annual greenhouse gas emissions, globally, are consistent with RCP 8.5.
But wait, the full Chapter 2 on climate science, box 2.4, is more nuanced (references omitted):
Which scenario is more likely? The observed acceleration in carbon emissions over the past 15–20 years has been consistent with the higher future scenarios (such as RCP 8.5) considered in this assessment. Since 2014, however, the growth in emission rates of carbon dioxide has begun to slow as economic growth has become less carbon-intensive with the trend in 2016 estimated at near zero. Preliminary data for 2017, however, indicate growth in carbon emissions once again. These latest results highlight how separating systemic change due to decarbonization from short-term variability that is often affected by economic changes remains difficult.
Well, which is it?
Here’s the IEA chart of global industrial emissions:
Emissions have been basically flat for five years. There has indeed been a small increase in 2017, and probably the first half of 2018, driven by an uptick in China. The NCA authors are reading an awful lot into this one datum. The trend in China for coal burn is down. That is what you would expect from the universal pattern of tertiarisation and energy efficiency pioneered by rich OECD countries. If you want anecdata, let me offer a very recent one: China has just suspended thermal coal imports because stocks are piling up in coastal power stations. I suggest the trend has resumed.
There is little reason to think we are on RCP 8.5. I suggest that the NCA authors, driven close to despair at their daily struggle to do their jobs in a criminally irresponsible Administration, are exaggerating the importance of its misdeeds. The median global government is not fantastic, but it is quite a lot better than Washington.
A more representative gloomy take is provided by Climate Action Tracker. They say that current policies (including fossil fuel subsidies) put us on a path to 3.1-3.7 degrees C of warming; current pledges, essentially the Paris Agreement NDCs, to a slightly better 2.6-3.2 degrees. I do not BTW understand their methods. China’s and India’s current policies are far more aggressive than their milk-and-water NDCs.
These ranges, and the roughly 3 degrees of warming they imply, may not look much better than RCP 8.5. However, one degree better is already halfway to the softer 2 degree Paris target. There is hope. Part of the Trump messaging strategy (we’ve seen it before) is to promote despair: things are hopeless, so let’s party on. Hope and progress, even modest progress, is dangerous to them. Mind you, 3 degrees of warming will be terrible enough. All the corals are gone at only 2 degrees, according to the IPCC.
As you know, I’m Pollyanna here. I think that all these policy wonks, through their déformation professionnelle, overestimate the importance of policy and underestimate that of mass production and economies of scale. The 10-year CAGR of solar PV installations is 43%, doubling every 2 years. The 5-year CAGR (10 years makes no sense) of electric vehicles is 77%, doubling every 14 months. Compound interest is the 500-pound gorilla, and King Kong is on our side.
An ingot of purified monocrystalline silicon. Suppose it’s 0.5m x 0.25m x 0.25m. At about 300 kilos, it’ll cost you about $5,000. By my rough calculations, it will make about 15 kw of solar panels, producing for 25 years. Current annual output of 100 GW of panels needs about 7 million similar ingots.
(4 wafers per mm = 2,000 wafers of 25 x 25 cm = 125 m2 of cells = 18.75 kw of panels at 150 w/m2, less 20% waste)