After weeks of speculation, the White House is expected to renege on America’s commitment to the Paris climate agreement, the Associated Press reported Wednesday.
It’s been less than a year since the U.S. formally endorsed the Paris accord, which has been ratified by 146 other nations since it was agreed upon in December 2015. The agreement calls on countries to reduce their greenhouse gas emissions in a bid to keep global warming below 2 degrees Celsius.
Though the globe appears off-track to hit this target, many scientists view the deal as an essential step in preventing global catastrophes wrought by drought, devastating storms, coastal erosion and the decimation of aquatic ecosystems like coral reefs due to warming and ocean acidification. The Paris accord also establishes an international bargaining table for the energy industry, given the intimate ties between fossil fuel power plants and greenhouse gas emissions.
What would really happen if we pull out of this deal? What would the Earth look like in 10, in 20, in 50 years without U.S. involvement in the Paris accord? We asked a field of experts.
Responses have been edited for length and clarity.
Michael Oppenheimer, Princeton University geoscientist and coordinating lead author of fifth United Nations Intergovernmental Panel on Climate Change report
U.S. emissions of greenhouse gases, particularly carbon dioxide, have been decreasing since about 2006. This is due fundamentally to changes in energy prices, which has favored natural gas over coal, and more recently, renewable energy like solar and wind over coal. It’s due to increasingly stringent regulations with the purpose of controlling air pollutants, which are dangerous to human health, to continual pressure on coal from a variety of other sources and to regulations of greenhouse gases implemented during the Obama administration.
Global emissions in fact may have peaked last year. They haven’t really changed much in the last three years, which is the first time that we’ve had such a flattening of emissions during the period of global economic growth. Even before the Paris agreement started to have much effect, there were trends in the world, which are starting to slowly bend the curve of greenhouse gas emissions.
Now the question is, can the Trump administration, by pulling out of the Paris agreement, throw sand into the gears, and either slow down or reverse the progress?
If the Trump administration withdraws from Paris, then during the first few years, there wouldn’t be very much difference in U.S. emissions, because, again, U.S. emissions aren’t so much driven by regulations yet, but by a whole other constellation of factors.
However, it is unlikely that all countries in the Paris agreement will continue to move aggressively to reduce greenhouse gas emissions if the second biggest emitter, the U.S., pulls out — particularly countries that are just starting to come to grips with the need to reduce their greenhouse gas emissions like India.