Across a vast swath of Europe and Asia, rain is increasingly falling in the short, localized bursts associated with thunderstorms, seemingly at the expense of events where a steady rain falls over many hours, a new study finds.

The study, detailed Wednesday in the journal Science Advances, directly links this trend to the warming and moistening of the atmosphere caused by rising greenhouse gas levels.

The results fit with rainfall trends already observed in the U.S., as well as model predictions that massive rains associated with thunderstorms could become both more frequent and more intense in the U.S. as the world continues to heat up.

The shift toward more extreme rains could have implications for water management and flooding because the ground is less able to absorb rainwater when it falls all at once.

“These changes should have pretty big impacts on this region,” Andreas Prein, of the National Center for Atmospheric Research in Boulder, Colo., said.

That a warming atmosphere will lead to more extreme rainfall events is one of the basic predictions of climate science, and is linked to the fact that warming leads to more evaporation, which leads to more water vapor in the atmosphere. That means that when rains occur, there’s more water vapor available to dump as rain.

Extreme downpours have already been increasing in the U.S., most notably in the Northeast, where they have increased by 71 percent since mid-century, according to the 2014 National Climate Assessment.

But rain comes in different types, namely convective and non-convective. Convection is the process that causes thunderstorms, and happens when there is strong warming at the Earth’s surface, creating an unstable atmosphere. That hot surface air rises, cooling as it does so, creating clouds and fueling heavy rain. It’s a short-lived, very local phenomenon that tends to occur most often in the summer. The skies can go from sunny, to downpour, to sunny again within an hour.

Non-convective precipitation, on the other hand, is typically involved with the passing of weather fronts and tends to lead to steady rains falling over several hours or days.

Full article