Precipitation variability increases in a warmer climate.

Area of Science:

• Climate Science
• Hydrology
• Meteorology

Background:

• Understanding the hydrologic cycle's response to global warming is crucial.
• Precipitation variability, unlike mean and extreme changes, is understudied.
• Precipitation variability is theoretically and practically important for climate impact assessments.

Purpose of the Study:

• To investigate projected changes in precipitation variability under global warming.
• To quantify the increase in precipitation variability across different timescales and regions.
• To compare projected changes in precipitation variability with changes in mean, extreme precipitation, and moisture.

Main Methods:

• Analysis of multi-model climate projections, specifically RCP8.5 scenarios.
• Examination of precipitation variability on timescales ranging from daily to decadal.
• Comparison of model outputs with observed daily variability in station data.

Main Results:

• Precipitation variability robustly increases over 66% of global land area in response to warming.
• Global mean precipitation variability increases by 3-4% K⁻¹, with higher increases over land (4-5% K⁻¹).
• Observed daily precipitation variability trends align with model projections.

Conclusions:

• Climate models consistently project an increase in precipitation variability with warming.
• The increase in precipitation variability is driven by increased moisture availability, partially offset by circulation changes.
• Projected increases in precipitation variability are significant and widespread, impacting future climate studies.