After months of delays and rumors of a divided White House, President Trump announced today his intent to withdraw from the international Paris Agreement to reduce greenhouse gas emissions, abdicating leadership on climate change.

Despite the public pronouncement, the US cannot simply quit Paris and go home. Per the terms of the agreement, the US cannot submit its withdrawal until November 2019, and it wouldn’t formally be out for at least a year after that. In the meantime, the Trump Administration could choose to skip international talks, but it will still have to submit some progress reports required by the deal. Of course, nothing stops President Trump from continuing to reverse Obama Administration efforts to reduce greenhouse gas emissions, support renewable energy production, or encourage efficiency improvements. The US will also renege on the remaining $2 billion of its promised $3 billion contribution (with more in the future) to the Green Climate Fund meant to help less-developed nations deal with the consequences of climate change and invest in renewable energy.

Speculation about this decision has been rampant since the election in November, as the issue was not as simple as a candidate who has publicly rejected climate science wanting out of a climate agreement. Many within the Trump Administration, including Secretary of State and former Exxon CEO Rex Tillerson and Trump’s daughter, Ivanka, have argued for staying in the agreement, which was signed by nearly every country in the world. Most fossil fuel companies have at least publicly stated the same desire, including the (current) CEOs of Shell and Exxon.

Trump would have had little to lose from remaining. Primarily because a Republican-controlled US Congress would have blocked a climate treaty, the Paris Agreement was structured around voluntary emissions pledges. The Trump Administration could simply have submitted a less ambitious pledge that did little more than bank on a continuation of market and efficiency trends. In fact, as The New York Times notes, some people think Trump could have done more harm to the goals of the Paris Agreement by staying and gumming up the works.

Apart from losing a seat at the table, the globalists in Trump’s orbit are concerned about the diplomatic consequences of ditching an agreement the US had previously signed on to. National leaders at last week’s G7 summit reportedly pressured Trump not to leave, and it’s unclear what effect the decision could have on other agreements. For example, negotiations between the Obama Administration and China produced a bilateral climate deal that helped pave the way for Paris.

In his remarks, President Trump claimed the US would be open to "renegotiating" the Paris Agreement to get fair terms—essentially a nonsensical statement given that the United States' terms are voluntary. He also claimed that the reason the world applauded the Paris Agreement was that it would exclusively harm the US to the economic benefit of every other country.

The ramifications of the decision for Earth’s climate are hard to define. If a new administration applies a strong course correction in four or eight years, the impact could be fairly small. An analysis by the team behind the Climate Action Tracker website projects that Trump’s various pro-fossil-fuel policies could potentially keep US emissions roughly flat through 2030, which would at that point represent about 2 billion more tons of CO 2 emitted per year compared to Obama Administration policies. (For context, that’s about 30 percent of current US emissions or 4 percent of current global emissions.) Trump Administration efforts to support fossil fuels over renewables face significant market headwinds, but the growth of renewables can certainly be blunted rather than accelerated.

The effect on future negotiations is another question. The Paris Agreement involves five-year milestones at which nations are meant to ratchet up actions from their previous pledges. With the US sitting these out instead of setting an example, there may be less motivation to improve on pledges. In an important way, this hinges on energy trends in China and India, and both nations have shown some encouraging signs recently.

China has publicly stated its intent to follow through on its Paris commitments regardless of what the US does. "We still uphold that all sides should move with the times, grasp the opportunities, fulfill their promises and earnestly take proactive steps to jointly push the enforcement of this agreement," Chinese Foreign Ministry spokesman Lu Kang said in March. "No matter how other countries' policies on climate change, as a responsible large developing country, China's resolve, aims, and policy moves in dealing with climate change will not change."

UPDATE: In response to the announcement, both Elon Musk and Walt Disney CEO Robert Iger stated on Twitter that they will be ending their involvement in advisory councils organized by the Trump Administration.

Am departing presidential councils. Climate change is real. Leaving Paris is not good for America or the world. — Elon Musk (@elonmusk) June 1, 2017