Who Leads When America Won't? The Post-COP30 Climate Landscape

Cora Jackson

COP 30 finished without the world’s largest economy at the table. While the absence of the United States at COP30 exposed the fragility of UN climate diplomacy, it also signals space for a new model of “green diplomacy.” In this new order, countries, cities, companies, and blocs can pursue ambitious and sustainability-focused deals without waiting for the participation of reluctant petrostates like Washington.

Delegations from 197 countries were present in Belém, Brazil, the location of COP30. The Amazon backdrop of this year's summit reflects Brazil's commitment to climate leadership. Brazilian President Luiz Inácio Lula da Silva has taken action to protect this rainforest, with deforestation reaching an 11-year low as it fell by 11 percent in the 12 months through July.

The United States, however, for the first time in COP history, did not send representatives to the summit following the Trump administration’s decision to close its office of climate diplomacy. In a similar vein, Trump has also withdrawn the U.S. from the Paris Agreement—the international agreement which implements the objectives of the UNFCCC. As a result, he has ceased implementing the Nationally Determined Contribution (NDC) outlined by the agreement, in which the U.S. had committed to reduce greenhouse gas emissions by 26-28 percent below 2005 levels by 2025. This absence is part of a broader retreat, as the United States has withdrawn from 66 international organizations and agreements, highlighting a major rollback of U.S. involvement in multilateralism.

Trump’s agenda is not entirely surprising. International momentum beyond Washington has also been stalled by disinterest. Ninety-five percent of nations failed to meet the February 10 deadline to submit their NDC pledges. These countries represent 83 percent of global emissions and 80 percent of the world economy. Most opted to announce their alternative plans prior to COP30, including underwhelming commitments from an array of nations--from China to Indonesia to Australia. This wider lack of good-faith participation at the conference signals a shift in the nature of the COP as a symbolic event instead of one that compels decisive action on behalf of the international community.  

When the world’s largest economy and historic emitter chooses not to attend amid broader retreats from climate ambitions, decisions at COP can no longer be treated as true representations of a “global consensus.” For instance, the world’s third largest emitter, India, was solely represented by its Ambassador to Brazil. Additionally, the Kick Big Polluters Out (KBPO) coalition calculates that one in 25 participants at COP are fossil fuel lobbyists, raising questions about the credibility and efficacy of the consensus-based negotiations. Such climate negotiations defined by coalition-building, broad multilateral participation, binding commitments, and accountability for large emitters are now a thing of the past. Current climate progress will depend on the states and actors who are willing to move together in their ambitious goals.

What does this new era of “green diplomacy” look like?

As the United States abandons COP leadership, a new era of climate leadership will emerge: climate progress led by those willing to act without waiting for Washington. This new era of “green diplomacy” represents a shift away from bureaucratic, multilateral climate action in favor of concentrated, purposeful partnerships. Such a “coalition of the willing” formed in response to Trump’s unpredictable attitude towards the war in Ukraine, when Europe rallied around Ukraine. Europe still pursued narrower alliances, coordinated aid, and instituted sanctions—all of which can be translated to the climate agenda. Similar coalitions can ensure the phasing out of fossil fuels, fostering clean-energy supply chains, and promote shared innovation. This diplomatic approach focuses on aligning specific economic, security, and environmental issues—not a rejection of the established UN system, but a parallel track that moves faster than COP consensus.

The EU has already begun to pursue this course of action through the recent EU-Mercosur trade agreement. This long-awaited agreement fosters free trade between the EU and Mercosur, a customs union comprised of Argentina, Brazil, Paraguay and Uruguay. The deal pairs market access with binding sustainability, labor, and anti-deforestation standards. The deal requires adherence to the Paris Agreement, serving as a test case for the feasibility of combining climate norms and economics. Mercosur’s novelty as a climate-aligned trade bloc makes it globally consequential for the future of climate diplomacy.

Other forthcoming leaders in the climate power vacuum include vulnerable highly ambitious states, large emerging economies and non-state and sub-state actors that see climate policy as an essential tenet of industrial and economic self-interest. Nations like Brazil and other forest nations are incorporating climate adaptation directly into their national agendas through investment in resilient infrastructure, sustainable agriculture, and renewable energy. The Vulnerable Twenty (V20) group, composed of the world’s most climate-vulnerable nations, launched the Global Shield Against Climate Risks to mitigate climate and disaster-related risks for their populations.

The U.S. absence from COP30 marks a serious change in the future of multilateralism and climate policy with broad implications for alliances and geopolitical influence. Contemporary climate diplomacy views civil society organizations, transnational networks, local environmental groups, cities, and businesses as powerful stakeholders in shaping climate action.