This World Politics in a Time of Populist Nationalism (WPTPN) guest post is written by Robert Y. Shum, an Assistant Professor of Political Science and International Studies at The College at Brockport, State University of New York (SUNY).

Does the Paris Agreement, and the likely withdrawal therefrom by the Trump administration, matter? On the surface, the current situation is not so different from George W. Bush’s withdrawal from the Kyoto Protocol. Probing deeper, however, important differences come to the fore. Many independent observers saw the Kyoto Protocol as fundamentally flawed in its lack of obligations applying to developing countries, including China and India. In contrast, an understanding between China and the United States lay at the center of the Paris Agreement.

Critics of the Paris approach to internationally-negotiated national emissions targets nonetheless argue that its effectiveness is limited compared to that of policies made at and by domestic institutions, regardless of the Parisian promise to broaden participation at the international level so as to include developing-country emitters. With the prospect that US participation in the international climate regime will be reduced under a Trump administration, the question regarding the value of participation in international agreements now shifts to the effect of US (non-)participation on the global climate regime. Minimizing this effect has become a source of hope and optimism. Thus, ironically, following Trump’s election, the critical view of Paris takes on a new function as both consolation for environmentalists and apologia for skeptics.

On the overall potential for agreement between the US and China, I had undertaken a bargaining-theoretic analysis in 2014 of what could be an acceptable outcome to climate negotiations between the United States and China. This analysis turned out to be consistent with the pledges ultimately made by both countries leading up to the Paris meeting. I must admit, however, that my prognosis for the political acceptability of such an outcome was mistakenly negative: I had not counted on the negotiators’ skilful framing of emissions limits as “peaks” to be reached over different timeframes by each country, rather than as numerical allowances that might otherwise have seemed highly unequal across the two countries (in static and absolute terms).

So did this negotiating success achieve anything, or are the critics right to scoff? It seems obvious to me that domestic acceptability is a prerequisite for any successful international agreement, and that criticisms on these grounds are bizarrely trivial. Most treaties are about winning support for an existing domestic policy program by easing concerns about foreign free-riding. By building trust, an effective international treaty regime works by promising further cooperation in the future. By including mechanisms for periodic reviews to “ratchet-up” obligations, the process emerging from the Paris Agreement promised new opportunities to develop norms for cooperative decarbonization. It is such a fresh start (rather than potential collapse of the existing liberal world order, as in the case of other fields such as trade and security) that has been lost with the election of Trump, to be replaced instead by a return to the previous collective-action deadlock.

So much for overall impacts and significance. In the short run, immediate questions also arise. One question is whether or not U.S. withdrawal will provide cover for other countries, such as India, to do the same:

India’s environmental minister won’t say whether nation will keep its climate pledge if Trump pulls the U.S. out of Paris deal. #COP22 pic.twitter.com/OCuobX5V6u

— Amy Harder (@AmyAHarder) November 17, 2016

In addition, it will be interesting to observe responses from the international community as a whole. Specifically, it is worth asking if the U.S. will pay a particular cost for climate isolationism. Prior to his defeat in Presidential primary elections, former French President Nicholas Sarkozy proposed a carbon tariff of an arbitrary 1-3% on U.S. exports:

Nicolas Sarkozy suggests slapping a carbon tariff on American exports if Trump pulls out of the Paris accord: https://t.co/TqCMTIanfZ

— Aaron Wherry (@AaronWherry) November 14, 2016

Ironically for an isolationist United States, the outcome of a prospective carbon-based global trade war would depend crucially on the role of the multilateral World Trade Organization (WTO). According to WTO law, border tax adjustments (BTAs) can be applied at a rate only up to an equivalent tax on domestic production. That is, the European Union (EU) could calculate the effective value of revenue collected from European producers through its Emissions Trading System (EU-ETS), and impose this equivalent rate on imports from the US. In contrast, if the EU were to impose an arbitrary tariff, even one intended to correct for the “harm” caused by production of the imports, it would be a violation of the principle of “non-discrimination” in international trade law, and constitute an almost textbook case of “disguised protectionism.”

It is possible that precedents will be set in the future to disincentivize the kind of backsliding that is likely to occur in the US, but such incentives are therefore likely to be as modest as any active steps that are taken domestically. Nonetheless, if Europe and China take up leadership on climate diplomacy in such a manner, then there would indeed be a possibility that a laggard United States would be left behind.

In sum, the Paris Agreement matters because signals about the likely course of future policies matter, especially in decisions at the margin about what kind of energy infrastructure and technologies to invest in. The climate can ill-afford restoration of a normative framework that encourages — even if only passively — policy inaction in what is both the world’s largest economy as well as the largest per-capita emitter among major economies. But that is precisely what election of the Trump administration promises. It is wishful thinking to believe that other countries will make up for the time that will be lost in the upcoming years. Damage will be done.

The Duck of Minerva’s WPTPN group is still seeking guest contributions. If you are interested in writing a post and have research expertise in international relations, international political economy, foreign policy, comparative politics, or cognate fields please see this post for more information.