When the temperature soars, coral reefs might cool off by creating their own clouds. Research from the Great Barrier Reef off the Australian coast shows that corals are packed full of the chemical dimethyl sulphide, DMS. In the air, DMS is transformed into an aerosol of tiny particles on which water vapour can condense to form clouds, which have a large impact on the local climate. DMS is also produced in large amounts by marine [...]