Robust Future Changes in Meteorological Drought in CMIP6 Projections Despite Uncertainty in Precipitation

• Published in: Geophysical research letters Vol. 47; no. 11
• Main Authors: Ukkola, Anna M., De Kauwe, Martin G., Roderick, Michael L., Abramowitz, Gab, Pitman, Andrew J.
• Format: Journal Article
• Language: English
• Published: Washington John Wiley & Sons, Inc 16-06-2020
• Subjects: Adaptation; Agricultural ecosystems; Agricultural management; Agriculture; Atmospheric models; Climate change; Climate models; CMIP6; Computer simulation; Drought; Duration; Ecosystem management; Intercomparison; Land area; Mean precipitation; Precipitation; Robustness; Security; Uncertainty; Water resources; Water resources planning; Water security
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2020GL087820

Quantifying how climate change drives drought is a priority to inform policy and adaptation planning. We show that the latest Coupled Model Intercomparison Project (CMIP6) simulations project coherent regional patterns in meteorological drought for two emissions scenarios to 2100. We find robust projected changes in seasonal drought duration and frequency (robust over >45% of the global land area), despite a lack of agreement across models in projected changes in mean precipitation (24% of the land area). Future drought changes are larger and more consistent in CMIP6 compared to CMIP5. We find regionalized increases and decreases in drought duration and frequency that are driven by changes in both precipitation mean and variability. Conversely, drought intensity increases over most regions but is not simulated well historically by the climate models. The more robust projections of meteorological drought compared to mean precipitation in CMIP6 provides significant new opportunities for water resource planning.
Plain Language Summary
Understanding how climate change affects droughts guides adaptation planning in agriculture, water security, and ecosystem management. Earlier climate projections have highlighted high uncertainty in future drought projections, hindering effective planning. We use the latest projections and find more robust projections of meteorological drought compared to mean precipitation. These more robust projections provide clearer direction for water resource planning and the identification of agricultural and natural ecosystems at risk.
Key Points
Quantifying meteorological droughts using changes in both the mean and variability of precipitation leads to more robust projections
CMIP6 projections show robust changes in the frequency and duration of seasonal meteorological drought over >45% of the global land area
Future drought changes are larger and more consistent in CMIP6 compared to CMIP5