In less than 100 days, the same 195 governments will gather in Glasgow at COP26, a necessary moment of truth.
Under the Paris deal all countries must deliver new, tougher emission cuts. The moment is challenging, but many will recall the uncertainty leading to the Paris agreement's finalisation. Collective interest prevailed, not because it was easy but because a spirit of stubborn optimism united world leaders against the common existential threat of climate change.
This stubborn optimism is why I am not put off by the objections of those with vested interests in fossil fuels that are approaching their expiry date. We know that the window of opportunity is closing and the only option is to do what science demands: eliminate fossil fuels and rebuild a flattened global economy.
Success at COP26 depends on three elements: first, all G20 countries must commit to cutting emissions by at least 45 per cent. To leaders in China, India and Australia who are yet to deliver 2030 targets, I say this: it is in your economic self-interest to accelerate your shift from coal-based electricity and start to address your looming transport emissions. The green economy is the growth story of the 2020s: 35 million new green jobs are expected by 2030.
Second: the world's wealthiest nations must deliver on their pledges. The US, EU, UK, Japan and other G7 nations must come forward with a financial delivery plan to support vulnerable nations by the time the UN General Assembly meets in September.
Third: CEOs of the world's leading corporations must face the reality that only through preventing the crisis can they have business continuity.
For too long big business has talked a good game, while working against decarbonisation behind the scenes. We need them to appoint climate experts to their boards, disclose their exposure to climate risks, clean up their supply chains and read the International Energy Agency's new net zero strategy.
This must be their playbook for the next decade because it will be their governments' regulatory handbook.
100 days is not long. UK PM Boris Johnson must deploy every lever he can find to encourage big emitters to deliver targets consistent with a 1.5C trajectory. This is no time for doubt — we have to trust Number 10 to do everything this moment calls for. Signs of progress are everywhere — from the US and EU's new carbon-cutting policies, to the climate prosperity plans from the Vulnerable 20 group of finance ministers, alongside innovations in the real economy.
The solutions exist today because the "Paris Effect" has already kicked in. The next 100 days are about timely delivery, as promised, requiring bold and decisive leadership. Every day counts.
• Christiana Figueres is a founding partner of Global Optimism and was the UN's climate chief from 2010-2016.
Written by: Christiana Figueres
© Financial Times