Last few weeks I have often been asked about the effect of the US withdrawing from the Paris accord—and yesterday it happened! It is a good question, but because there are countervailing factors the answer is not straightforward—the net effect ranges from minimal to quite profound.
The Paris Agreement is not a binding treaty; it requires voluntary cuts to emissions of greenhouse gases, mainly CO2. The desired target set by the Intergovernmental Panel for Climate Change (IPCC) is to cut energy-related global CO2 emissions from the current 36 Gt-CO2 each year to about 17 Gt- CO2 by 2035 and then be net zero by 2050. If all the signatory nations cut their emissions by the amounts they have pledged, the global emissions are slated to rise to 55 Gt- CO2. Clearly, all nations will have to do a whole lot more if the IPCC targets are to be realized. Indeed, it was the expectation that the signatory nations will periodically review their progress and make additional pledges.
Trump questioned the "fairness" of the agreement by saying that it imposes undue economic burden on US while allowing developing nations to continue emitting CO2. Like I said, no nation is imposing any burden on any other nation. It is all based on independently determined voluntary contributions. Also, I wonder what is Trump's definition of fairness. China may have higher emissions than the US, but per capita emissions in the US is twice as high as in China and much higher than in much of the developing world. Moreover, the US, and other developed nations have been adding copious quantities of CO2 to the atmosphere since the start of the industrial revolution. They have reaped all the benefits of industrialization. The developing nations, with a much larger population, have only recently begun the process of improving the lot of their citizens by expanding energy use. Asking them to share equally in cutting emissions? Now that’s unfair!
As far as global emissions are concerned, the rest of the world will continue to make progress. In the US too, progress will continue along that front thanks to economic factors (i.e. cheap natural gas) and actions at state and city levels. The repeal of rules implemented under Obama’s Clean Power Plan (CPP) does remove incentives for auto manufacturers to produce more fuel-efficient vehicles, including electric cars. That action will likely result in the US ceding leadership in electric cars and batteries to manufacturers in Europe and Asia. The repeal of CPP is not likely to increase coal use for power generation—liberalization of Oil and Gas industry will increase the production of natural gas, which will continue to be fuel of choice for power production. Switching out coal for natural gas will reduce U.S. emissions, but the lack of regulations and requirements for monitoring fugitive natural gas—a far more potent greenhouse gas than CO2 —could wipe out any benefits there may have been from fuel switching.
A real opportunity for reducing emissions lies in the advanced nuclear technologies. I spoke on the topic two weeks ago. I devoted much of my talk to addressing the widely-held fears and risks of nuclear power, and on the newer thorium-based nuclear technologies that are walk-away safe and generate a very small amount of radioactive waste that would require safeguarding—essentially, burial under six feet of ground—for only about 300 years.
My talk can be viewed here. Unfortunately, since the slides cannot be seen very clearly in the video, I have posted them my Google Drive and you can download them here. It is a long video (about 1.5 h including Q&A), but I hope you can make time to view it. I would be most interested in hearing about any comments or questions you might have, and particularly so if after you viewing you still think that the world would be better off not developing nuclear power.