Tiny organisms on the ground – bacteria and fungi – have a “superpower” that allows them to reach up into the atmosphere and pull down the rain, according to a recent study.

To understand how a microbe can control a storm, we first have to look at how clouds become rain. High up in the atmosphere, water doesn’t always freeze at 0°C. Temperatures are normally much lower at cloud level but pure water can stay liquid down to a bone-chilling -40°C.

Most rain starts as ice. In the atmosphere, clouds are full of “supercooled” water – liquid that is colder than freezing but hasn’t turned to ice yet because it has nothing to hold onto.

For a cloud to turn into rain or snow, it needs a “seed”– a tiny particle for water molecules to grab onto so they can crystallise into ice, then fall from the clouds as rain. Dust, soot and salt – swept into the clouds by wind – can do this, but they aren’t very good at it. They usually require the temperature to drop significantly before they start working. This is where biology enters the frame.

For decades, scientists have known about ice-nucleating proteins (INpros) found in certain bacteria like Pseudomonas syringae. Bacteria travel from plant leaves into the clouds to trigger rain. They use special proteins to force water to freeze at temperatures as high as -2°C.

However, the recent discovery published in the journal Science Advances has revealed a new player in the climate game: fungal INpros. While bacteria keep their ice-making proteins........

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