How does fungi trigger ice in clouds?
Fungi and ice formation: how microbes could change cloud physics
Research is exploring whether fungi can influence ice formation in clouds—an effect that could matter for weather and climate because ice processes strongly affect cloud lifetime, precipitation, and how much sunlight Earth reflects.
Clouds form when water vapor condenses into tiny droplets. For many types of precipitation, those droplets must eventually become ice crystals. In the atmosphere, ice does not form just because temperatures drop; it often needs surfaces or “ice-nucleating particles” that help water molecules organize into a solid lattice.
What the new research suggests
Scientists describe a plausible mechanism: fungal proteins may be able to freeze water at relatively warm subzero temperatures compared with what would otherwise be needed for spontaneous freezing. If real-world fungal material in the air behaves similarly, it could provide efficient seeds for ice within the temperature range typical of mixed-phase clouds.
Why this could matter
Even small changes to the rate at which clouds transition from liquid water to ice can shift:
- When and how precipitation starts, affecting rain and snow timing.
- Cloud optical properties, influencing how clouds interact with solar radiation.
- Cloud coverage and persistence, which can feed back into broader weather patterns.
The big uncertainty
While the concept is scientifically coherent, the headline implication depends on how much biologically derived ice nucleation actually occurs in natural clouds, which depends on emissions, atmospheric transport, and concentrations of viable fungal components.
Still, the work positions fungi as more than background bioparticles. If validated in atmospheric measurements and modeling, it would add a biological pathway to the physical processes that govern precipitation—an area historically dominated by mineral dust, soot, and other non-biological aerosols.