Soil (Photo credit: arimoore)
Some computer models for global warming may be over-estimating the risk of drought, according to a study published on Wednesday by the journal Nature.
Several key models used in climate research that factor in warming trends suggest that droughts will intensify as world temperatures rise.
This is on the basis that dry soils have less moisture to suck up into the atmosphere, which reduces rainfall and thus causes even greater aridity.
But scientists are worried that these models are too large in scale and lack observational data, especially about what happens locally.
Seeking to plug the knowledge gap, a four-nation team led by Chris Taylor from Britain's Centre for Ecology and Hydrology looked at images from weather satellites which track the development of storm clouds across the globe.
The scientists say they were surprised when they matched where new storms appear alongside images of how wet the ground was.
They found that afternoon storms were likely to occur when soils were parched -- not over soils that were moist.
The apparent reason: drier soils create stronger warm winds called thermals, which boost the chance of rain.