Extreme weather events, such as heavy rainfall, are likely to occur more frequently and with greater intensity in the coming years. With a warming of 1°C, extreme precipitation events that occurred only once every ten years in pre-industrial times are expected to happen on average about 1.3 times more often. If the Earth warms by 4°C, it is projected that such extreme precipitation events will occur almost three times more frequently each year.
As temperatures rise, precipitation, evaporation, and groundwater recharge are changing. With increasing air temperatures, more and more water evaporates from streams, rivers, and lakes. Water stored in the soil escapes into the air, leaving less water available for plant growth. The warmer the air is, the more water vapor it can hold, and the more rainfall is subsequently possible.
