Trump Pulls the U.S. Out of Paris Climate Accord

Now that President Trump has withdrawn the U.S. from the international climate agreement that seeks to limit future greenhouse gas emissions, it’s worth asking a few questions. What exactly did President Obama commit the U.S. to in Paris in 2015? How significant are U.S. emissions relative to the rest of the world’s? And what are U.S. emission levels likely to be now that Washington has left the pact? (President Trump has left open the possibility of rejoining the Paris accord later, but under what terms is unclear.)

Of course, whether to participate in the Paris deal is largely a political question of public policy, and one that arouses strong feelings. I won’t wade into the arguments surrounding Trump’s decision. But energy consumption is really the issue. And that’s a topic where some objective, apolitical analysis is possible.

First, what did the U.S. initially promise to do? Reduce U.S. emissions of carbon dioxide and other greenhouse gases by between 26% and 28% by 2025, relative to 2005 levels.

Why is 2005 the benchmark year? Probably because emissions of greenhouse gases were near an all-time peak in 2005: The equivalent of about 7.3 billion tons of CO2, according to the EPA. Emissions have since fallen, so cutting from a higher starting point makes for an easier goal.

How much does the U.S. emit now? How does that compare to other countries? The EPA hasn’t compiled emissions data for 2016 yet, but in 2015 the U.S. released 6.6 billion tons of CO2 and equivalent gases. That means that U.S. emissions had already fallen by 9.5% from the 2005 baseline: A significant head start on the 26% to 28% cut that Obama pledged.

And when the EPA does publish 2016 emissions levels, chances are the data will show a further reduction from 2015. Why? Consumption of coal, the most carbon-intensive fossil fuel, fell dramatically last year. In other words, the U.S. is already making significant strides in reducing its greenhouse gas emissions, largely because utilities are switching to cleaner natural gas to generate power. Also, renewable power generation is growing rapidly.

The U.S. is the second-biggest carbon polluter, according to data from, a British website that tracks climate-related topics. The website pegs the U.S. share of worldwide emissions at 12%, compared to almost 24% for China, the top emitter. The entire European Union accounts for 9%.

Clear of Paris, will U.S. emissions rise now? Probably not. Trump has begun nixing Obama’s climate regulations. But he will probably replace them with less-stringent regs that still limit CO2 emissions. Plus, as I have noted before, many state and local governments will continue limiting emissions within their borders or encouraging renewable energy.

More importantly, the long-term trend in the U.S. energy sector is clearly toward less coal, less oil, more natural gas and more renewables. Consider: Between 2005 and 2016, U.S. annual coal consumption fell from 1.1 billion tons to 730 million tons. During the same span, oil use fell from 7.6 billion barrels per year to 7.2 billion (even as Americans drove more miles). Gas, the lowest-carbon fossil fuel, rose from 22 trillion cubic feet consumed to 27.5 TCF. And the U.S. increased its wind-generated power by a factor of 12.

What is the rest of the world pledging to do? It varies. Some countries are committed to strict reduction targets. The EU, for instance, is promising a sharp 40% emissions reduction compared to 1990 levels by 2030. Brazil is shooting for a 37% cut from 2005 by 2025.

But some other big polluters are only promising to lower their emissions relative to their economies’ GDP. India, the world’s fourth-largest emitter, is pledging a roughly one-third reduction in the so-called carbon intensity of its economy by 2030, which doesn’t necessarily mean emissions would actually fall. And China, the biggest emitter, aims to start lowering its CO2 output by 2030, which would allow its emissions to keep rising for more than a decade.

Many smaller countries are pledging various reductions, too, mostly contingent upon receiving “international support” in the form of financial aid to help pay for more renewable power or other measures.

With or without the U.S., will the Paris climate accord work? That depends on how you define “work.” The signatory countries, which include everyone but Nicaragua and Syria, committed to preventing global average temperatures from rising by 2 degrees Celsius from their pre-industrial level. But when I attended a meeting of a major environmental group in Washington, D.C., in 2015, the gathered policy analysts stated that the emission cuts likely to be pledged at Paris would fall short of this goal, according to the U.N.’s own climate-change computer models.

(And keep in mind that these analysts and their organization supported the Paris plan, arguing it was the best deal they could realistically expect. They also viewed Paris as a diplomatic milestone for international cooperation on emissions reductions.)

Projecting the planet’s future climate is a daunting task. So too is imagining how much and what types of energy the world will run on in a decade or two. Technological and economic changes between now and then are hard to imagine. But when it comes to the U.S., it seems safe to bet that energy supplies will keep trending toward no- or low-carbon sources, mostly for economic, rather than environmental, reasons. Abundant shale gas makes a coal comeback unlikely. Ever more fuel-efficient cars will keep eating into future oil demand. The costs of wind turbines and solar panels are likely to keep declining, making them more competitive with fossil fuel-powered electric generators.

And those factors are unlikely to change, no matter who occupies the White House.