An estimated 300 deaths were reported, and waterborne diseases began to spread in the wake of the floods. Within a few weeks, World Weather Attribution issued its verdict: climate change had led to an increase in rainfall intensity of approximately 40%.
Then the global donor community did what it always does when a climate disaster strikes Africa or another developing region. They blamed climate change, presenting it as an abstract collective failure with no single culprit. The victims were poor, but no specific culprits could be identified. No one was held accountable.
Perhaps that era has now come to an end—not in Maputo, but in the haze over New Jersey.
When smoke from hundreds of Canadian wildfires turned the sky orange over much of the United States, causing tens of millions of football fans to wonder whether the world’s most popular sporting event would be disrupted, President Donald Trump responded not with cooperation or mutual aid, but with a demand for accountability. He declared that America had suffered an “unjustified invasion” by Canadian pollution. The Canadian government has shown willful negligence in managing its forestry sector and must therefore face increased tariffs.
A Critical Threshold Has Been Crossed
Climate change policy has crossed a critical threshold. For the first time, a major power has taken steps to demand payment for cross-border damage caused by climate change and to unilaterally seek compensation (in this case, from a friend, neighbor, and ally).
What was once a matter of development, insurance, or emissions accounting has now turned into a bilateral dispute over security and trade between two G7 countries. We are witnessing the first international conflict related to climate and security.
The irony of the situation is obvious. For a decade, Canadian Prime Minister Mark Carney was the world’s most influential financial expert on climate issues. As the first and most authoritative central bank governor to warn of the “tragedy of the horizon,” he gave the financial industry permission to view climate change as a source of financial risks—some of which are physical in nature, while others stem from a broader economic transition.
However, as prime minister, Carney faces pressure from his domestic coalition, which is demanding an expansion of oil and gas production, as well as from the U.S. administration, which, brandishing tariffs, is demanding increased production, the construction of new pipelines, and the wider use of the very fossil fuels that contribute to the increased frequency and intensity of wildfires.
This episode shows that science will not be the arbiter of climate-related costs; instead, they will be weaponized by those who wield coercive power. The smoke is Canadian, the carbon is global, and the tariff is American.
This pattern will be familiar to developing countries. Back in 2019, the Group of Twenty (G20) suspended multilateral funding for oil and gas exploration in developing countries simply because it could, ignoring the consequences for economic growth in those countries.
Climate change knows no borders
The dispute between the U.S. and Canada marks the beginning of a new era, as the laws of physics guarantee that such events will recur.
The fires in Los Angeles in January 2025 have already become one of the costliest disasters in history, but they were confined to a single country.
This will not always be the case. Smoke, floodwaters, and drought-induced migration know no borders. India, Pakistan, and China rely on rivers fed by the Himalayas; six countries are already disputing control over the Mekong River’s flow; Senegal is bearing the brunt of increasing amounts of Saharan dust from Mauritania; and displaced populations are constantly putting pressure on Europe.
Each of these factors represents a “smoke tariff” just waiting to be imposed.
If the U.S. can impose tariffs on Canadian smoke, shouldn’t Mozambique—a country suffering from a problem it had no part in creating—have the right to make claims against the largest sources of emissions?
Small island states have already brought this issue before the International Court of Justice (ICJ). Can’t they now cite the United States’ behavior as evidence that the damage caused by climate change constitutes interstate damage subject to legal action?
If such damage is indeed real, quantifiable, and attributable to a specific source, someone must pay for it.
In fact, the economics of a securitized approach to addressing climate issues—in which everyone acts in their own self-interest—are disastrous.
If Europe adopts a “fortress” mentality, its decarbonization process will slow down, and by 2050 it will lose approximately 14% of its potential production capacity.
Insurers warn that fragmentation is already keeping capital outside national borders, leading to the formation of regional risk pools that are too interconnected to be diversified, and causing a reduction in insurance coverage in areas with a high concentration of risks. Responding to climate-related damage through premiums will accelerate these trends.
A Shared Problem and Shared Security
Instead of trying to improvise from crisis to crisis, policymakers should focus on three priorities.
First, they must view climate resilience as a form of common security. Carney is right to emphasize that combating climate change is every country’s responsibility, but his call has gone unheeded.
Despite decades of joint U.S.-Canada efforts to fight wildfires, introducing tariffs currently appears to be a simpler way to share the burden. However, jointly investing a portion of the revenue from these tariffs in firefighting, protecting watersheds, and improving the resilience of energy systems would help, at the very least, neutralize the potential for such measures to be used as a means of exerting pressure.
The second priority is to establish dispute-resolution mechanisms before the situation worsens. The world needs a common, science-based mechanism—not leverage—to assess cross-border climate damage.
Perhaps artificial intelligence could offer solutions. Who has contributed what? Who has failed to adapt? And who, therefore, owes what to whom?
Small island states and the V20 group have spearheaded this dialogue and secured an advisory opinion from the International Court of Justice, as well as the establishment of a UN fund for loss and damage. These measures must now be strengthened. Trade rules must distinguish between legitimate carbon levies and coercive climate protectionism.
The third priority is to prevent the pitting of sovereignty claims against decarbonization. The dispute between the U.S. and Canada is based on the assumption that climate costs should reflect someone’s negligence rather than being a collective consequence of accumulated emissions.
This way of thinking inevitably allows the largest emitters to turn the costs of their own inaction into a lever for exerting pressure.
The best alternative to the logic of border taxes is sustainable and effective carbon markets that link emissions, market access, and financing and investment in climate change adaptation in a coordinated and predictable manner. Perhaps the time has come for a real discussion of global emissions trading markets.
The smog over New York and New Jersey eventually cleared enough for Spain to win the World Cup, while Trump and Carney watched from the stands.
But a precedent has been set. Climate activists have long asked whether countries will cooperate to prevent damage. Now we must ask what governments will do as the damage mounts. Will they find a better solution than settling scores with one another at the border? The world’s first battle for climate security does not inspire confidence, but there is still time.
Vera Songwe,
a nonresident senior fellow at the Program on Global Economy and Development and the Africa Growth Initiative at the Brookings Institution, is the founder and chair of the Liquidity and Sustainable Development Fund.
© Project Syndicate, 2026.
www.project-syndicate.org
