The stark gap in vaccination rates between the world’s rich and poor countries is emerging as a test for how the world responds to another global challenge: Averting the worst effects of climate change.

Of the more than 1.1 billion vaccinations administered globally, the vast majority have gone into the arms of people who live in the wealthiest countries.

This gap presents an object lesson for climate action because it signals the failure of richer nations to see that it is in their self-interest to urgently help poorer ones fight a global crisis.

The United States has blocked efforts at the World Trade Organization to relax patent rules for Covid-19 vaccines, and pharmaceutical industry groups and their backers in the White House have opposed sharing intellectual property with rival drug makers.

This battle over intellectual property rights also has a parallel to climate action, with the Paris climate agreement calling for the transfer of technology to develop clean energy infrastructure.