After years of preparation, and two weeks of furious negotiations, the Global Warming Summit in Paris finally produced an agreement that has been hailed as “historic, durable and ambitious”. On 12 December 2015, the representatives of all 196 countries pledged to limit their carbon emissions to relatively safe levels that would keep global warming below two degrees Celsius. They also agreed to regular reviews of these commitments to ensure that they can be increased in line with future scientific advice. Both developed and developing countries will be bound by these accords, and the rich countries agreed to raise $100 billion (€90 billion) a year by 2020 to help poor countries transform their economies.

This agreement was the culmination of more than 23 years of international attempts under the UN to forge collective action on this global problem. Those efforts were marked by discord and failure, the refusal of the biggest emitters to take part, ineffective agreements and ignored treaties. Many of these obstacles have now been overcome, but like any international compromise, it is not perfect. 

Critics point out that the caps on emissions are not firm enough and could lead to warming above the two degree threshold. A consensus of scientists say two degrees is the limit of safety, beyond which the effects – droughts, floods, heat waves and sea level rises – could become catastrophic and irreversible. The overall agreement is legally binding, but some elements, including the pledges to curb emissions by individual countries, are not. But even with these imperfections, it is an important milestone in international cooperation.

Kumi Naidoo, executive director of Greenpeace International, summed it up this way: “It sometimes seems that the countries of the UN can unite on nothing, but nearly 200 countries have come together and agreed to a deal. Today, the human race has joined in a common cause. The Paris agreement is only one step on a long road and there are parts of it that frustrate, that disappoint me, but it is progress. The deal alone won’t dig us out of the hole that we’re in, but it makes the sides less steep.”