Global drought trends under 1.5 and 2 °C warming

Global drought extremes are projected to increase under future warming scenarios. However, global drought risk and pattern remain to be revealed below 1.5 and 2 degrees C warming levels. Here we used multi-model simulations to estimate global drought trend based on multiple drought indicators. The frequency and duration of meteorological drought may increase much faster than surface soil moisture drought and root zone soil moisture drought under anthropogenic warming, with a probable similar to 36% (62%) increase in frequency and a similar to 15% (20%) increase in duration at 1.5 degrees C (2 degrees C) level relative to the reference period over the globe. A 5% (14%) increase of drought frequency is expected at 1.5 degrees C (2 degrees C) warming in the surface soil moisture, and a 5% (2%) increase of duration is also likely in the 0-10 cm soil layer. Unprecedented increased drought risk is anticipated at 2 degrees C level, with potential drought hot spots in North America, South America, southern Africa, Australia and Europe. Drought condition under future warming may be much worse in local areas. The drought frequency in the drylands is much less (> 34%) than the humid areas, but the duration is much higher (> 40%). The 2 degrees C relative to 1.5 degrees C warming is expected to bring higher drought risk than the 1.5 degrees C relative to 1 degrees C period with regard to the frequency.