CO2 doesn’t respect national borders. If ‘small’ emitting countries don’t act, the maths of tackling climate change simply doesn’t add up.
Like a single ant, countries each emitting around 1% or less of global CO2 emissions can look tiny on their own. Step back and you see how they shape the whole. Together, the world’s ‘negligible emitters’ account for about 30% of its CO2 emissions – roughly the same as China, and more than the US, India and the EU combined.
Tackling climate change is a global coordination challenge, with the logic of a prisoner’s dilemma: everyone benefits if all countries take action, but each is tempted to wait and see if others move first. Even the largest emitters don’t capture most of the benefits of their own emission cuts, because those benefits are shared globally. If every smaller-emitting country sat this out, the numbers wouldn’t add up.
A useful analogy is taxation. One person may contribute less than 0.001% of a country’s tax revenue, but that does not mean they (and others) can simply opt out. Collective systems only work if participation is broad enough to sustain them. The same logic appears in overfishing: no single greedy boat collapses a fishery, but if everyone takes a little too much, the system breaks.
The politics of climate change make it harder still: the near-term costs of domestic action are often concentrated and visible, while the benefits are distributed globally. That means free-riding may look tempting – some politicians are trying it – but it breaks the maths at the global scale.
That’s why multilateralism still matters. Even under intense strain, coordination through forums like the UN, alongside smaller coalitions of the willing, builds trust and shows momentum. As more countries move, costs fall, deployment rises, and inaction becomes harder to justify on economic and political grounds.
Climate diplomacy often focuses on the ‘big four’ – China, the US, India and the EU – because their choices largely determine the global emissions trajectory. But stopping global heating requires something much broader: a world in which every nation, large or small, achieves net zero in the second half of this century or earlier.
That’s the internal logic of the Paris Agreement. It respects national sovereignty and different development paths, while requiring all countries to submit climate plans and progressively strengthen them over time, according to their ‘highest possible ambition’.
The Paris framework explicitly recognises that responsibility and capability are not evenly shared. Countries that have contributed least to historical emissions, and that face more pressing development challenges, are not expected to transition at the same speed as wealthier nations, who should reach net zero first. This principle – known as ‘Common But Differentiated Responsibilities and Respective Capabilities’ (CBDR-RC) – lies at the heart of the Agreement. In practice, this shows up in different timelines: the EU aims for net zero by 2050, whereas India targets 2070.
The atmosphere doesn’t care about borders, population or geopolitics. It responds only to cumulative emissions. Every tonne counts, wherever it comes from.
