With the news that the Trump Administration has signaled its intent to withdraw the United States from the Paris Agreement, I reached out to a number of leading experts on global climate governance and U.S. climate policy for advanced comment. Contributors include Jessica Green, Jennifer Hadden, Thomas Hale, Matthew Hoffmann, Angel Hsu, Joanna Lewis, Johannes Urpelainen, and Stacy VanDeveer.

I asked all of them to reflect on the following three questions. 1) What do you think the the consequences of U.S. withdrawal will be for the agreement? (2) How do you think other actors will respond to U.S. withdrawal in terms of their own commitments and actions? (3) What affect will this move have on U.S. standing in the world?

What follows is my synthetic take on people’s answers, my own editorializing, and then each scholars’ full comments unedited. I also have a piece this afternoon on the decision on The Monkey Cage.

Contributors to the forum are sanguine that the agreement will survive and indeed that withdrawal may in the short-run spur a commitment by leading countries, sub-national governments, and private actors to up their efforts. On some level, U.S. withdrawal could be good for the agreement if staying in meant that it sucked up all the energy and time by seeking to renegotiate the terms. Since withdrawal is not immediate, what role the U.S. will play in the interim remains to be seen. If recent discussions in Bonn are an indication, that may mean sending a skeletal crew of junior people to sit on the margins.

U.S. withdrawal creates space for the EU and China to position themselves as they have already done as global climate leaders. Over the longer-run, however, it may be harder to sustain a “race to the top” when other countries observe the United States’ backsliding in the domestic sphere. We should have a better sense in 2018 when progress to date and the rules for how to track and review pledges are set to be finalized. The loss of U.S. contributions on global climate finance appears highly likely, which may, in turn, dampen other contributions, a very bad omen for international efforts to support adaptation and resilience.

While the agreement can survive four years without the United States, eight years of a hostile Trump administration would pose a more significant challenge since the world needs U.S. participation (namely, domestic action) for the agreement to be effective. The commitments made in Paris in 2015 were a down payment on what is required to have an even outside chance of keeping temperatures from rising more than 2 degrees Celsius above pre-industrial levels. If we cannot ratchet up ambition in 2020, then we are in for a world of even more significant warming and weird weather than any of us are prepared for.

All of the contributors agree that this is a major unforced error by the United States, which was totally unnecessary given the flexibility of the agreement. After having exercised 8 years of leadership to remove the stigma of previous inaction, the United States has reversed course and punched itself in the face at a moment when the rest of the world is poised to move on to next generation clean energy that will protect the planet and be the source of jobs and wealth in the future. The best case scenario at this point is that United States elects a new president in 2020 who reverses course and promptly re-joins the agreement in January 2021. Until then, we’ve got some work to do.

1) What do you think the the consequences of U.S. withdrawal will be for the agreement?

Jessica Green, New York University

I am optimistic about this. The administration has already managed to alienate its allies on other issues; this will be another one to add to the list. The net effect of this, I think, will be to unify the other major emitters, and reinforce their commitment to climate leadership. I don’t think that the agreement will fall apart, though I concede that US withdrawal might embolden some laggards. But already, major powers have reaffirmed their support – including the EU, China and Russia.

It’s already clear that the business community will continue to develop pro-climate policies, even without the US in the Paris Agreement. States and cities are also forging ahead. NYC Mayor de Blasio says that NYC is aiming to exceed the US goal of 28% below 2005 levels by 2030. Again, this just demonstrates that the train has left the station on climate. Pretty much everyone else is on board.

An appropriate analogy here is the UN Law of the Sea. The US signed, but never ratified this treaty, which governs maritime activities – from fishing and shipping to navigation and safety. Virtually every other country in the world has ratified, and the treaty has been relatively effective (with the notable exception of managing the world’s fisheries). The US also essentially abides by all the rules, although it is not a party. US non-participation hasn’t upended the agreement by any stretch of the imagination. There’s good reason to think that the same will hold for Paris.

Jennifer Hadden, University of Maryland

Ultimately, global greenhouse gas emissions are the only thing that matters for the climate. The Paris Agreement will continue without U.S. participation, as other world leaders have made clear. The main challenge in reducing emissions globally will be to secure sufficient support for domestic implementation of countries’ climate pledges (the NDCs) without U.S. involvement. It was widely thought that U.S. funding, technical cooperation, and support/pressure would be critical in translating the NDCs into real action.

Other actors (state and private) may try to fill the gap on finance, but I’m skeptical that other actors will be able to play the leadership role as effectively in the short term.

Thomas Hale, University of Oxford

The good news is that Paris was designed to be resilient to political shocks like Trump. The withdrawal will only kick in after the next presidential election, meaning the US may never actually exit the Agreement. However, 2018 is a critical year for implementation of the Paris Agreement. Countries have agreed to finalize by the end of 2018 the “Paris rulebook”—including the regulations around how national pledges will be be tracked and reviewed, and the process through which countries will ratchet up their commitments in the future. Getting these details right is crucial for the long-term success of Paris, and the US has often been a strong force for good on these kinds of transparency requirements. Trump makes it much harder for the progressive countries to shift the traditional laggards on these issues.

Also in 2018, the UNFCCC will hold a “facilitative dialogue” to take stock of the current national pledges, as well as action by cities, business and others, in order to kick off the process of putting forward a new round of pledges in 2020. It’s crucial to build positive political momentum around this moment in order to close the emissions gap by 2020, and US backsliding will have the opposite effect.

Matthew Hoffmann, University of Toronto

U.S. withdrawal may matter little to the functioning of the Paris Agreement. The decentralized nature of the agreement (Hale 2016; Keohane and Victor 2016, Falkner 2016) insulates it to some extent from the recalcitrance or absence of any one party. Long-term, the Paris Agreement needs the US if it is to be an effective agreement in the sense of achieving its goal of limiting warming to 2 degrees, but in the short term U.S. withdrawal won’t necessarily hurt the functioning of the Paris Agreement.

Withdrawal is a symptom of the larger problem of U.S. hostility towards climate action under the Trump Administration. So many of the things that observers are worried about in terms of consequences of U.S. withdrawal (e.g. loss of U.S. leadership, loss of funding pledges, signaling that scaling back commitments is okay) are happening anyway. This means that there is at least the possibility that the US withdrawal will be good for the Paris Agreement. With the US getting out of the way, there is opportunity for other countries to lead and for there to be an increase in solidarity around implementing Paris commitments.

Angel Hsu, Yale-NUS College

“Thank you Trump,” tweeted former Executive Secretary of the UNFCCC Christiana Figueres, half tongue in cheek. “You have provoked an unparalleled wave of support for Paris and determined resolve on climate action. Deeply grateful.” Like Figueres, I am cautiously optimistic that the Trump Administration’s announced withdrawal from the Paris Agreement will backfire and the mounting backlash will lead to stronger climate action in the near and long-term.

The Trump Administration’s announcement is, on its face, disastrous for global climate action. The move, however, has incited a backlash from leaders inside the U.S. and abroad that promises to swamp the Administration’s efforts to undermine multinational climate diplomacy. Former New York City Mayor Michael Bloomberg today pledged $15 million to the UNFCCC, replacing the funding that would be pulled with the U.S.’s departure. Mayors of 83 U.S. cities, representing more than 40 million Americans, responded to Trump’s announcement vowing to “adopt, honor, and uphold the commitments to the goals enshrined in the Paris Agreement.” These subnational leaders, along with the presidents of more than 80 universities and hundreds of businesses, have formed a coalition that is negotiating with the UNFCCC to have its dedication to the Paris Agreement’s goals and targets accepted alongside national contributions. The governors of Washington, New York, and California have meanwhile formed an alliance reaffirming their shared commitment to meet the Agreement’s goals. These states account for about one fifth of U.S. population and GDP. These immediate reactions fill me with hope that the Administration’s decision will merely give the U.S. a diplomatic black eye but will not have lasting repercussions for global climate action.

Joanna Lewis, Georgetown University

The involvement of the United States in the international climate negotiations for the past eight years has been extremely constructive. US leadership was instrumental in mobilizing the support of key countries like China and India, which built the momentum needed to get 195 countries to support the agreement. US withdrawal will certainly be a disappointment to the international community, but one that has been anticipated since November.

As I witnessed in Bonn last month, the US was already playing a substantially reduced role in the negotiations, and was hesitant to commit to much in the face of domestic policy uncertainty. So short of a complete policy reversal on climate change from the Trump Administration, even if the US were to stay in the agreement it is likely they would have played a significantly diminished role, if not a destructive role.

Johannes Urpelainen, Columbia University

It’s hard to say whether U.S. withdrawal is better or worse than the alternative. On the one hand, withdrawal may complicate future re-engagement under a less hostile president or encourage some other countries to consider the exit option. On the other hand, withdrawal would prevent the Trump administration from sabotaging the negotiations and allow other governments to move forward.

Stacy VanDeveer, University of Massachusetts-Boston

I’m persuaded by Hoffmann & others arguments that it is not clear at all that the US staying is better for the climate regime than a full US withdrawal. Staying in offers lots of opportunities to create problems. The UNFCCC system, in the short and medium term, seems likely to chug slowly along. With committed US leadership, it may stay a rather slow place for progress, but since the option of committed global US leadership on climate (and on many other things) was taken off the table by American voters I’m not sure the near term impacts on the climate regime are that bad.

Now in terms of specific topics in the regime, the impacts may be different. So financing will be harder with the US outside, I suspect. Liability and damages discussions? I’m not, given how hostile the US has been to serious language (let alone action) on that front. In terms of rule setting and implementation review, I imagine deals struck between Brussels and Beijing will become the global norms and processes. I think the most important near term domestic consequence is that it muddles messages to market and US state and local actors about federal energy & climate policy – slowing some progress that would otherwise be achieved. But again, domestic impacts of Paris withdrawal are hard to separate of the asinine energy & climate policies of this administration, generally.

Last words from me on this: A larger and negative set of consequences will be seen in other global/multilateral fora. If Trump officially withdraws, it is that much more likely that the administration and its minions work to block climate and energy policy development on other forums (and this, I think, has mostly been missed in commentary to date). So – G7, UNSC & USGA, World Bank, the Ozone regime, etc. – will probably now all be places where US officials work to block/impede/derail climate and clean energy progress and where the US finds itself alone and isolated.

(2) How do you think other actors will respond to U.S. withdrawal in terms of their own commitments and actions?

Jessica Green

This is where the picture is perhaps not as rosy. Paris depends on what one scholar, many years ago, referred to as “tote board diplomacy”: basically, public commitment and transparency would socialize governments into a culture of complying, and eventually, ratcheting up their commitments.

Without US involvement, tote board diplomacy can’t work as well. Countries or regions that lead will have a harder time sparking a “race to the top”. Low income countries are a different story. It’s pretty clear that there will be no more US funding for adaptation, or any of the number of funds associated with the UNFCCC process. This will not only hurt developing countries, but provide political justifications for less (or no action).

Jennifer Hadden

Indications are that other countries still intend to make good faith efforts to implement their current NDCs. The fact that so many countries have adopted domestic climate laws or executive actions supporting their NDCs is evidence that this is already happening. But if there is not sufficient support or pressure for implementation, we should expect more countries will miss their targets. Current NDCs were never sufficient to address the climate challenge – the “ratchet mechanism” was introduced because of the need to increase ambition over time. While I think the current round of NDCs will still more or less stand, the ratchet is likely in danger.

The Paris Agreement still enjoys widespread support from non-state actors. It’s notable that the negotiations around Paris included a parallel process to garner commitments from cities, states, and firms. I’ve always thought of this non-state action as the “resilience plan” of the Paris Agreement, and this is where it will be most useful. I think that this non-state action will continue, and may even strengthen in some cities and states if climate action becomes part of the ‘resistance.’ However, Paris was important (in part) because it provided a signal to markets regarding the direction of future policy. If that signal is muddied, private actors may not act as aggressively in the short term regarding investment decisions and R&D.

Thomas Hale

Trump just launched a massive natural experiment (without ethics approval!) that tests a fundamental IR theory about collective action. Countries made their Paris pledges with the expectation that the US would likely fulfill its target. Now that Trump has made clear this is not going to happen under his watch, will other countries continue to cooperate or defect in the face of US free-riding? My expectation is that the bottom up nature of the Paris Agreement makes it likely almost all countries will follow through on existing pledges. Indeed, all major emitters have pledged to do. In a few years we’ll know the answer.

More difficult to know is how this will affect the next round of pledges scheduled to be delivered in 2020. Will countries raise their ambition in the face of US defection? I think many will need a push (perhaps from a newly confident China, transnational city and business networks, civil society, or others) to get there. But at the same time, contra the conventional wisdom on collective action, for a good number of actors Trump’s withdrawal will actually increase the incentive to do more. Mayors and governors in Democratic-leaning areas can score electoral points by taking matters into their own hands. CEOs and investors with planning horizons beyond 4-year electoral cycles will move to ensure they will not be caught out by the climate regulations that could likely follow Trump in the 2020s (many of those that do business abroad, that is most big firms, are already becoming Paris-compliant to manage global regulatory risks and costs). And, in electoral politics, Trump is politicising what has traditionally been a low salience issue by associating it so personally with his own polarizing brand. For some key voting blocks—e.g. young people—this could be an enthusiasm booster in 2018 and 2020.

Matthew Hoffmann

That’s the million dollar question. So far the rhetoric coming from Europe, Canada, China, and India seems to indicate that other countries will respond by isolating the US on this issue and carrying on with implementing their commitments under Paris. The real test of this will come in 2018 in the initial stock taking to see if those initial defiant responses translate into long term commitment to act on climate change.

Beyond states, I expect sub and non-state actors to step up as they have before when the international process stalls or is steeped in uncertainty. The number of actors, and especially major corporations, urging the US to stay in Paris (which is fundamentally a proxy for urging the US to act responsibly on climate change) has been impressive. These actors will hopefully now put actions behind these words, moving on climate change in the face of US withdrawal.

Angel Hsu

There is cause for optimism that other nations will reaffirm their commitments to the Paris Agreement goals in the wake of the Trump Administration’s announcement. National leaders in China and the EU have reacted to the U.S.’s withdrawal with defiance, framing climate action as an opportunity to collaboratively reshape their societies to be more resilient and prosperous in the face of rising global temperatures and sea levels. It is true that the U.S.’s outlying position will give cover to countries that are unable or unwilling to meet their pledged goals. Free ridership is a slippery slope, and if the U.S. abandons multinational climate diplomacy other nations may follow.

Yet the Trump Administration has, through words and deeds, positioned itself as a sole actor on the global stage, vowing to go it alone without mind of allegiances and alliances. “America First” is not a slogan that engenders international support or begs other nations to follow. The current administration is unpopular at home and abroad, making it an easy decision for world leaders to stand in opposition of its decisions. By turning away from international climate diplomacy, President Trump may spur other nations to double down on their own commitments in defiance of his much maligned regime.

Joanna Lewis

We have already seen all the major economies speak out against the US decision to withdraw from the Paris Agreement. It will most certainly damage our relationship with the EU, Germany and France in particular. While the EU has long been a global leader on climate change, it is somewhat surprising how outspoken China’s leaders have been in reconfirming their support for the Paris Agreement in the face of US withdrawal. China and the United States moved in lockstep over the past four years as they jointly announced their national pledges, signed the agreement, and then ratified the agreement. But China appears to be poised to continue to move forward even without the US by its side. Forceful statements from President Xi Jinping in Davos, followed by China’s U.N. ambassador in New York, have reaffirmed the country’s position to remain in the Paris Agreement and fulfill its international obligations. Given recent coal consumption trends, China increasingly looks on track to meet its Paris pledges ahead of schedule.

Johannes Urpelainen

Because the Paris Agreement allows countries to choose their own actions, most governments are unlikely to react strongly. They have already chosen targets that are in their self-interest, and U.S. withdrawal is unlikely to have large impacts on the costs and benefits of climate mitigation. Some non-state actors may increase their ambition and the European Union or China could try to re-claim climate leadership.

The most serious problem that Trump’s hostile position creates is climate finance, as industrialized countries will find it difficult to meet their goals without the United States, but this problem would be present even if Trump remained inside as a hostile participant.

Stacy VanDeveer

In the climate regime, I think the best way to understand other responses may be in terms of leaders, laggards and middling followers (or some such typology). That is, Trump taking the US out probably straightens the spines of leaders and encourages them to push harder, faster (and try to accrue domestic and international gains from this). It probably also emboldens laggards – those states and firms who were mostly pretending to endorse Paris and its implementation.

For the middlings/followers, their reactions seem likely to respond to both Trumpian policies and others’ responses to it. So, if EU and Chinese actors can double down on rhetoric and commitments and progress over the next 6-14 months, then they might offer followers incentives and paths toward progress. If they do not, and the regime simply chugs along with traditionally slow progresss, I think followers and indifferent actors simply ride along on their indifferent, low ambition pathways.

Lastly, I agree with the conventional wisdom that US withdrawal is a big win for China (globally) in terms of both soft power aspects and econonmic and development and political cooperation across the developing world and in Europe. The Europeans MUST have a partner to continue to lead on slow, global progress. With the US out, they have only one option: China. This is a win for China.

(3) What affect will this move have on U.S. standing in the world?

Jessica Green

The US will lose big on the global stage by withdrawing. All issues are connected, and our foreign policy agenda (such as it is) will suffer greatly from our unwillingness to cooperate on climate. This happened with Kyoto, when Bush announced the US withdrawal.

I also agree with the conventional wisdom, bolstered by the upcoming EU-China statement on their commitment to cooperate on climate policy, that rising powers like China are ready and willing to step into the void.

Jennifer Hadden

Leaving the Paris Agreement will create credibility problems for the United States in other realms of international cooperation, making it harder to achieve U.S. foreign policy goals. It will also damage bilateral relations with key countries, especially big emitters like the European Union and developing counties that were counting on U.S. assistance.

More generally, this decision erodes global goodwill towards the United States, which may have lasting reputational consequences.

Thomas Hale

It’s hard to imagine a better way to squander so much influence for so little gain. Trump has given every country in the world a legitimate reason to resist US diplomatic pressure on every other issue he holds dear: trade, migration, terrorism, etc.

Moreover, in many countries around the world, opposing Trump’s climate belligerence will score big points in public opinion, giving politicians of every stripe an incentive to resist US interests.

Matthew Hoffmann

It’s fairly clear that this will be a significant blow to US standing in the world. Especially coming on the heels of the disastrous NATO meetings, the US seems intent on convincing the rest of the world that it does not care about or intend to uphold long standing commitments to international order.

The world is learning very quickly to not trust the US under the Trump administration.

Angel Hsu

The administration’s announcement will certainly diminish the U.S.’s standing on the international stage, and not only in climate diplomacy circles. It is clear that Europe’s progressive leaders view the Trump’s decision as a rogue act. French President Emmanuel Macron made sure to point out that his American counterpart acted in opposition to the will of the American people, calling Trump’s decision a step taken by “the United States federal government.” Even before Trump’s announcement, German Chancellor Angela Merkel suggested that Europe could no longer count on the U.S. and that, “Europeans must really take our destiny into our own hands.”

President Trump’s decision to withdraw from the Paris Agreement is yet another diplomatic disaster for the U.S., a move that distances us from our allies and exacts untold damage on our reputation in the global community. This is not the first time, however, that our seemingly schizophrenic government has exposed its fickleness to the world. The George W. Bush Administration abandoned the Kyoto Treaty within months of taking office in an act that Trump now echoes. The peculiarities of the U.S. electoral system allow for such unwelcome vicissitudes (both Bush and Trump lost the popular vote). The administration’s withdrawal may, paradoxically, strengthen international support and engagement with U.S. subnational and non-state actors. California’s governor Jerry Brown arrived in Beijing today intending to bolster his state’s relationship with China, opening a new avenue of climate diplomacy. Brown will host a Global Climate Action Summit next September in San Francisco, meaning that the U.S. will promote international climate negotiations even without the federal government’s acquiescence. American business leaders of all stripes have spoken out against the U.S. withdrawal, showing resolve to pursue climate action, with or without the federal government, in an increasingly globalized world. These budding relationships and coalitions will build international repute for America’s subnational and non-state actors while the federal government’s world standing sinks.

Joanna Lewis

Relinquishing its global leadership role on climate change will greatly diminish the ability of the United States to shape multilateral outcomes in which it has a stake. In addition, walking away from climate and energy cooperation could be destabilizing for the broader U.S.-China relationship. During the eight years of the Obama administration, there was no other issue on which the countries had greater common interest.

As the US steps aside, it is creating a void that other nations are likely to fill. And there are already signs that China may take on an enhanced global role. The Chinese government is host to two key international meetings in Beijing next week that were originally conceived by the U.S. government as part of its broader climate and energy strategy, the 8th Clean Energy Ministerial and 2nd Mission Innovation Ministerial. These events are a great opportunity for China to demonstrate its new leadership on climate change and clean energy.

Johannes Urpelainen

Given that the vast majority of the world’s governments and people consider climate change a serious threat, withdrawal would further undermine the reputation of the United States and isolate the Trump administration.

Stacy VanDeveer

Of course it will be hard to separate the impact for US standing of this one decision from the overall impacts on US of the Trump administration generally. But it my view the biggest impacts are: (1) a nearly instant return of the US reputation for not keeping most of the promises it makes in multilateral fora; (2) an acceleration of US blaming and anti-US rhetoric in domestic politics around the world; and (3) a consequent weakening of US negotiating positions in most multilateral fora. As during the depths of the Bush II administration, I think we will see a lot more use of climate and a small number of other issue around the world by domestic leaders who gain support by condemning the US, its president, its immorality, its irresponsibility, the threats it poses, and so on.