It would only cost $50bn to ensure 40% of the world’s population is vaccinated by the end of the year, and 60% by the first half of 2022.

This is a recent estimate from the IMF, the latest institution to join a chorus of voices calling for a global vaccination program to bring Covid-19 under control. The IMF has highlighted the economic benefits of global vaccines, which would be huge. But there is another powerful reason for a worldwide campaign.

Vaccinating the world will be crucial if countries are going to act together to confront the climate crisis, which will require many of the same things as delivering vaccines: resources, innovation, ingenuity, and a true partnership between rich and developing countries. The Cop26 climate conference in November will be an opportune moment for building this partnership. But to do so, rich countries need to deliver on their early promises to deliver global vaccines.

As it stands today, vaccine access is deeply unequal. The US is starting to vaccinate children, even as health workers and elderly people are waiting for shots in most of the world. At the end of April, less than 2% of the population of Africa had been vaccinated, while 40% of the population of the US and 20% of the population of Europe had received at least one dose. India, one of the largest vaccine manufacturers in the world, has fully vaccinated 3% of its population and is still in the middle of a nightmarish second wave that has forced the country to stop exports of all vaccines.