Global exposure of population and land‐use to meteorological droughts under different warming levels and SSPs: a CORDEX‐based study

SPINONI, JONATHAN; BARBOSA, PAULO; BUCCHIGNANI, EDOARDO; CASSANO, JOHN; CAVAZOS, TEREZA; CESCATTI, ALESSANDRO; CHRISTENSEN, JENS H.; CHRISTENSEN, OLE B.; COPPOLA, ERIKA; EVANS, JASON P.; FORZIERI, GIOVANNI; GEYER, BEATE; GIORGI, FILIPPO; JACOB, DANIELA; KATZFEY, JACK; KOENIGK, TORBEN; LAPRISE, RENÉ; LENNARD, CHRISTOPHER J.; KURNAZ, M. LEVENT; LI, DELEI; LLOPART, MARTA; MCCORMICK, NIALL; NAUMANN, GUSTAVO; NIKULIN, GRIGORY; OZTURK, TUGBA; PANITZ, HANS?JÜRGEN; ROCHA, ROSMERI PORFIRIO; SOLMAN, SILVINA A.; SYKTUS, JOZEF; TANGANG, FREDOLIN; TEICHMANN, CLAAS; VAUTARD, ROBERT; VOGT, JÜRGEN V.; WINGER, KATJA; ZITTIS, GEORGE; DOSIO, ALESSANDRO

INTERNATIONAL JOURNAL OF CLIMATOLOGY

JOHN WILEY & SONS LTD

Año: 2021

0899-8418

Global warming is likely to cause a progressive drought increase in some regions, but how population and natural resources will be affected is still underexplored. This study focuses on global population and land-use (forests, croplands, pastures) exposure to meteorological drought hazard in the 21st century, expressed as frequency and severity of drought events. As input, we use a large ensemble of climate simulations from the Coordinated Regional Climate Downscaling Experiment (CORDEX), population projections from the NASA-SEDAC dataset, and land-use projections from the Land-Use Harmonization 2 project for 1981-2100. The exposure to drought hazard is presented for five SSPs (SSP1-SSP5) at four Global Warming Levels (GWLs, from 1.5° to 4°C). Results show that considering only Standardized Precipitation Index (SPI; based on precipitation), the combination SSP3-GWL4 projects the largest fraction of the global population (14%) to experience an increase in drought frequency and severity (versus 1981-2010), with this value increasing to 60% if temperature is considered (indirectly included in the Standardized Precipitation-Evapotranspiration Index, SPEI). With SPEI, considering the highest GWL for each SSP, 8 (for SSP2, SSP4, and SSP5) and 11 (SSP3) billion people, i.e. more than 90%, will be affected by at least one unprecedented drought. For SSP5 (fossil-fueled development) at GWL 4°C, approximately 2·106 km2 of forests and croplands (respectively 6% and 11%) and 1.5·106 km2 of pastures (19%) will be exposed to increased drought frequency and severity according to SPI, but for SPEI this extent will rise to 17·106 km2 of forests (49%), 6·106 km2 of pastures (78%), and 12·106 km2 of croplands (67%), with mid-latitudes being the most affected areas. The projected likely increase of drought frequency and severity significantly increases population and land-use exposure to drought, even at low GWLs, thus extensive mitigation and adaptation efforts are needed to avoid the most severe impacts of climate change.