A Moroccan soldier stands guard outside the COP22 Climate Change Conference in Marrakesh on Monday. (Stephane De Sakutin/AFP/Getty Images)

As Donald Trump prepares to take office in January, climate scientists and activists have begun to speculate about how his presidency could affect the success of the Paris climate agreement. And in fact, just one week in, Trump’s election has already begun to make waves in the dialogue surrounding the international community’s climate efforts.  

On Monday, former French president Nicolas Sarkozy suggested that Europe impose economic repercussions on the United States should Trump actually withdraw from the Paris agreement as he’s promised.

“Donald Trump has said that he would not respect – it will be seen whether he sticks to this commitment – the conclusions of the Paris accord on climate,” Sarkozy told the French television station TF1. “And so I ask that Europe construct a carbon tax at Europe’s borders, a tax of one to three percent for all the products that come from the United States, if the United States exempts itself from the environmental regulations that we ourselves have imposed on our businesses.”  

Such a move could be a major blow to American exporters — and the suggestion isn’t without teeth. Sarkozy, who was president of France from 2007 to 2012, is currently considered a front-runner to become the center-right Les Républicains party candidate in next year’s election.

The comments came as representatives from around the world entered into their second week of meetings at the UN climate change conference in Marrakech, Morocco. There, attendees are now considering the potential future of the Paris accord minus U.S. involvement.  

Climate experts have expressed doubts about the international community’s ability to meet its global climate goals — namely, keeping global warming within at least a 2-degree temperature threshold — if the United States fails to follow through on its national commitments. And some are also concerned that a U.S. withdrawal could weaken other nations’ resolve to stick to their own climate pledges.

In fact, ripples from Trump’s election have already made themselves apparent a little closer to home. In Canada, the election results have caused a renewed conservative push-back against Prime Minister Justin Trudeau’s plan for a nationwide carbon price.

Last month, Trudeau announced he would allow Canadian provinces two years to come up with their own carbon pricing schemes, before moving to have  the federal government impose one upon them. Trudeau has proposed a minimum price tag of $10 per metric ton of carbon dioxide starting in 2018, gradually increasing to $50 per ton by 2022. Currently, Alberta and British Columbia already have set prices on carbon, and Ontario and Quebec are in the process of moving forward with their own carbon pricing schemes.  

The proposal was met with immediate backlash at the time from conservatives, who argued that the plan was too heavy-handed. And now, critics are pointing to the impending Trump administration as another reason to abandon the plan. They’re arguing that the extra costs imposed by the carbon price will make Canadian businesses less competitive with U.S. firms operating under an administration that promises corporate tax reductions and vows to eliminate federal spending on climate change policies.  

“That criticism hasn’t been all that new,” said Werner Antweiler, an expert in international trade and environmental economics at the University of British Columbia. “But what has changed is that the opponents of any form of carbon pricing feel emboldened by the fact that there will probably be no carbon policy at the federal level in the U.S. for the next number of years.”  

For his part, Trudeau has pledged to stick to his carbon pricing plans, despite the outcome of the U.S. elections. But as the aftershock of Trump’s election continues to reverberate, some experts are arguing that more action is needed to bolster the Paris agreement against a possible U.S. drop-out.

In a recent paper published in the journal Climate Policy, environmental policy expert Luke Kemp of Australian National University outlined a number of ways that participants in the accord could attempt to “U.S.-proof” the agreement. One strategy could be to implement penalties, such as trade restrictions, for parties who drop out.

In fact, Kemp said, “Sarkozy’s idea of a one to three percent carbon tax on U.S. imports was exactly the kind of idea I had in mind.” But he added that this idea is something of a “nuclear option,” and may not be all that politically feasible for the time being, especially if it came down to getting other nations like China on board.  

Another, perhaps less politically sensitive, move he suggested is making a place for subnational players — that is, cities and states — in the accord. Even under the Trump administration, it’s likely that climate-conscious states and municipalities will continue writing their own carbon-cutting policies, and there are ways that the Paris accord could take those into account, Kemp said.  

“The weakest way would be to simply set up a framework to recognize and review subnational actors,” Kemp told The Washington Post. “And that could be a way to not just encourage subnational action in the U.S., but also identify where there’s areas for investment and areas for encouragement.”  

Even this framework could potentially promote greater action at the federal level, Kemp suggested. There’s a precedent for national environmental policies being inspired by state-level action: Federal fuel efficiency standards for vehicles, developed under the Obama administration, were largely the product of clean car standards first enacted in California, for instance.  

A more stringent framework would be to actually facilitate a linkage in carbon markets between U.S. subnational actors and other countries. But there’s little precedent for this kind of action and it would likely be more difficult to accomplish.  

Another idea, Kemp suggested, would be for the world’s biggest carbon emitters — China and the European Union, for instance — to forge their own separate climate agreement without U.S. participation. It could exist alongside the Paris deal, but would also help safeguard the world’s climate goals against a possible collapse of the accord in the event of a U.S. withdrawal.  

Any of these actions would take time and extensive negotiations to implement, and it’s unclear whether the international community would be open to restructuring the existing agreement at this time. But Kemp argues that it’s important for the global community not to take Trump’s threats lightly when the accord, in its current form, includes no concrete ways of addressing non-compliance.  

And even now, world leaders are already vowing to hold the U.S. accountable for its future actions.

“The United States, the largest economic power in the world, the second-largest greenhouse gas emitter, must respect the commitments they have undertaken,” said French President Francois Hollande during the ongoing climate conference in Marrakech. “France, I can assure you this here, will lead this dialogue with the United States and its new president in openness, in respect, but with demands and determination, on behalf of the 100 states who have already ratified the Paris Agreement.”