On the shores of the Caspian Sea, less than 30 miles from the place where world leaders, ministers and negotiators are meeting at the COP29 climate summit in Baku this week, a powerful greenhouse gas has been venting into the atmosphere.

A sensor installed on the International Space Station detected six separate plumes of methane between April and June. According to the California-based non-profit Carbon Mapper, which analysed the data and shared it with the Financial Times, all were traced to oil and gas sites on the outskirts of Azerbaijan’s capital.

A further five plumes were detected at other sites in the country, including near the giant Sangachal oil and gas terminal. Although they varied in intensity, they were both polluting and deeply toxic, containing carcinogens and other dangerous gases as well as methane.