As world leaders descend on Baku for COP29, a familiar yet unsettling pattern seems poised to repeat itself. Global climate summits, from Kyoto to Paris, have always been imbued with hope that nations could unite against a common existential threat. Yet, as time progresses and the stakes rise, an inconvenient truth is becoming increasingly evident: a warming world is likely to fuel division, not unity.

The ideal response to climate change, as almost every economist and climate scientist would agree, is robust international cooperation. A globally coordinated carbon tax, stringent cross-border decarbonization commitments, and large-scale resource transfers to support vulnerable nations are the textbook solutions to this planetary crisis. Such measures would address the essence of climate change—a global externality that demands a global response. But the realpolitik of climate negotiations has always fallen short of this ideal. National priorities, economic rivalries, and the pressures of domestic politics have consistently derailed aspirations for united global action.

COP29 arrives at a moment of deepening climate nationalism, and this is true not only in light of Donald Trump’s return to the White House. Initiatives like Biden’s Inflation Reduction Act in the United States or carbon border taxes in other jurisdictions are not just climate policies; they are assertions of economic sovereignty. These measures seek to accelerate the green transition but do so through protectionist frameworks that prioritize national interests over global collaboration. The notion of a concerted global response becomes more elusive when every major player is focused on securing a comparative advantage in the technologies of the future. In effect, these policies, while beneficial in accelerating national decarbonization efforts, come with the risk of fragmenting global markets and straining international alliances.

This is not to suggest that international cooperation is a lost cause. Multilateral meetings like the COPs can be a useful avenue for coordination, discussion, exchanges of best practices, agreements on standards (e.g. on carbon credits), and some positive peer pressure. Beyond this, small coalitions, regional agreements, and sector-specific treaties can still drive meaningful progress. For instance, climate clubs, in which a group of nations agrees to impose common carbon pricing or trade standards, could provide an alternative route to the fractured multilateral approach. 

Yet, the larger truth is hard to ignore: climate change will likely exacerbate geopolitical rivalries, not dissolve them. As the impacts of climate change intensify—unequally distributed across regions—national leaders will be under pressure to safeguard their own populations, reinforce borders, and pursue self-reliant policies. The fear of resource scarcity and climate-induced migration will likely make these nationalist tendencies more pronounced. Wealthy nations may continue to pledge financial support for vulnerable regions, but history suggests that these commitments will fall short of what is needed. This has proven true once again at the latest biodiversity COP in Cali.

Drawing from a range of disciplines, including evolutionary biology and historical analysis, in a new paper I show how humans, in the face of existential threats, tend to rally around their closest groups. In today’s world, the most cohesive and politically powerful group remains the nation-state. It is a sobering realization: the era of climate-induced scarcity and uncertainty will likely fortify nationalist impulses, making grand international agreements harder to achieve. Human societies have historically responded to crises by strengthening in-group solidarity, often at the expense of broader cooperation. This psychological and cultural tendency makes the vision of a unified global climate front seem increasingly utopian.

This evolution should inform expectations for COP29. Success may not come from sweeping global pacts but from a recognition that climate nationalism is now an inescapable feature of climate politics. If the world’s major powers leave Baku having agreed to imperfect, nationally-focused but pragmatic climate policies, it may be disappointing—but not entirely unexpected. In fact, agreements that emphasize national self-interest, while suboptimal from an efficiency standpoint, may be more resilient in the face of political and economic shocks.

COP29 may well be a pivotal moment, but its legacy will depend on how well it navigates this tension between the ideal and the real. The world should not give up on the dream of international cooperation, but it must acknowledge the constraints imposed by human behaviour and political realities. The focus must now be on blending national self-interest with strategies that still advance global goals, fostering technological innovation, and building adaptive capacities. The coming decades will test humanity’s ability to adapt not only to a changing environment but to a new era of climate politics defined by national, rather than collective, ambition.