Donald Trump will enter the White House with an environmental policy agenda opposed to that of the Obama administration and many other nations that have pledged support to the Paris climate agreement. The Washington Post's Chris Mooney breaks down what a Donald Trump presidency will mean when it comes to climate change. (Daron Taylor/The Washington Post)

This story  has been updated.

The surprise election of Donald J. Trump to the presidency of the United States Tuesday night didn’t just stun global markets. It also hurled doubt into international climate change negotiations currently underway in Marrakech, Morocco this week, as participants contemplated vows by Trump, a climate change doubter, to “cancel” the Paris climate agreement that had brought them together.

“Science cannot expect any positive climate action from him,” Hans Joachim Schellnhuber, head of the Potsdam Institute for Climate Impact Research, said in a statement. “The world has now to move forward without the U.S. on the road towards climate-risk mitigation and clean-technology innovation.”

It’s not immediately clear what the election means for the world’s quest to cut its greenhouse gas emissions, which in recent years has begun to gain long-awaited momentum, due in no small measure to U.S. leadership.

The Paris agreement was forged, in significant part, by sustained diplomatic moves by the Obama administration, which worked closely with China to bridge the gap between developing and developed countries that had bedeviled attempts at such agreements in the past. Only by having the world’s two largest emitters on the same page did real progress come to seem possible. Dozens of other nations quickly fell in line.

The Paris Agreement is expected to come into force within the next few months. The Post's Chris Mooney explains where we go from here. (Daron Taylor/The Washington Post)

But if the United States backs out on Paris and ceases to participate, it’s unclear what global repercussions might follow. If the United States is no longer promising significant emissions cuts, why should major developing economies like India, which is racing to supply electricity to its immense population, stick to their own targets?

“Atmospheric chemistry doesn’t change because Trump won an election,” said Paul Bledsoe, who worked on climate change issues in the Bill Clinton White House. “And businesses know they will inevitably face long-term carbon constraints. Even the Paris Agreement will far outlast his presidency. But U.S. international credibility on climate negotiations is gone.”

Michael Oppenheimer, a professor of geosciences and international affairs at Princeton University, largely agrees. He said the scientific community must do its best to convince Trump that the problem of global warming is real and urgent, and that the only way to avert serious climate consequences is for the United States to lead the world in cutting carbon emissions substantially. But he acknowledged that the president-elect has so far show little inclination to embrace that view.

“Moving forward, if Trump doesn’t change his view of the Paris agreement and doesn’t honor the commitments [the Obama administration] made, that virtually guarantees that the international process will fall into disarray.”

Under the Paris process, each nation sets its own target to lower its emissions — in effect pledging to the rest of the world that it is good for its word. If countries not only fail to hit their targets, but fail to jointly strengthen them over time, that could mean blowing past key planetary guardrails.

Repeated analyses, including one released by the United Nations’ Environment Programme (UNEP) last week, have shown that countries are still emitting way too much carbon dioxide to the atmosphere to hold the warming of the globe below key targets in the Paris agreement. If that doesn’t change soon, these temperature thresholds could be crossed.

Looming first of all is 1.5 degrees Celsius. The world is already about 1 degree C warmer than in pre-industrial times, and the UNEP report found that unless the globe as a whole limits its emissions and starts to bring them down by the year 2020, it will likely pass 1.5 degrees C, locking in a range of climate change impacts.

Countries would need to make stronger pledges than the ones currently on the table in order to keep targets like 1.5 degrees within reach. Without the United State’s participation and leadership, it’s not clear how ambitious they would be.

UN Environment head Erik Solheim insisted that the vast majority of countries, as well as the business community, will push on with climate efforts no matter what a Trump administration brings.

“The drive for change is unstoppable,” Solheim said in an interview Wednesday. “The United States is the most powerful nation in the world, the most important nation in the world, but it’s not the world. The world will continue to move, whatever happens.”

Solheim said he remains “fundamentally optimistic” that the Paris agreement will remain intact, and he said that if the United States were to walk away from its pledges, Americans themselves would suffer, particularly in the loss of business opportunities that cleaner energy brings.

“We look forward to working with him and his administration for the good of the planet,” Solheim said of Trump, adding that it was too early to tell the repercussions of the election. “Of course, we want the United States to play a role … The global community will judge the United States on its actions, and we’ll see what happens in the months to come.”

Granted, U.S. emissions could still decline even without Trump’s Paris participation — a switch from burning coal to burning natural gas for electricity is already contributing to a reduction, at least to an extent. And the world may just keep pursuing its own actions under the agreement regardless of the tack the U.S. takes.

“The commitment of the international community is irrevocable, and global progress will continue regardless of the level of U.S. participation,” said Phil Duffy, president of the Woods Hole Research Center. Duffy added that many other actors will still continue moving to cut emissions, from local governments to corporations.

It’s also unclear precisely how Trump’s administration would attempt to exit the Paris climate deal, assuming that Trump sticks to his campaign pledge. The agreement just entered into legal force, which means the U.S. cannot technically withdraw for four years.

Trump energy adviser Kevin Cramer, a U.S. representative from North Dakota, recently stated that a Trump administration would submit the agreement for a ratification vote in the Senate, which would likely fail. The Obama administration had held that ratification was not necessary.

In coming months, U.S. science agencies are likely to make official the determination that 2016 was the hottest year in recorded history, surpassing the previous record holders, 2014 and 2015. If international climate measures stumble, there could be many more such records to come.

Ultimately, Solheim said environmental advocates also must do some “soul searching” of its own.

“We were not able to make the environment an important issue in the American election,” Solheim said. “The environmental community must ask why this didn’t become a kitchen-table issue in Montana or Kansas.”

Read more at Energy & Environment:

Why scientists are so worried about sea-level rise in the second half of this century

We’re adding record amounts of wind and solar — and we’re still not moving fast enough

Trump victory reverses U.S. energy and environmental priorities

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