Examining the contribution of human induced climate change on global drought characteristics

Drought is generally considered a slow process natural hazard. However, the faster onset and strength of recent events have received great attention. Climate change and human activities can both play a role in altering the characteristics of droughts, including their speed of development and intensity. Climate change can, for example, indirectly impact droughts by changing the amount and distribution of precipitation, while human activities, such as land management, can directly alter the water content of the soil. In this study, we run the JULES-W2 land surface model with the counterfactual stationary ISIMIP3a climate dataset, a hypothetical climate without climate change [1], and transient land use changes based on observations. We use soil moisture as a water deficit indicator and a framework for calculating the hydrological drought propagation speed [2] to define drought characteristics. We compare results against those calculated from historical runs with climate-related forcing based on observations (factual) to examine historical imposed long-term changes attributed to human-induced climate change. Our results show that climate change could significantly impact the speed of development and intensity of droughts. Some regions like Congo rainforest, Europe and the western US are simulated as hot spots of more fierce droughts, while others (e.g. East African mountains) may have faced milder droughts as a result of climate change. These changes can have important consequences for the productivity of agricultural lands, the health of ecosystems, and the availability of water for human use. Future climate change highlights the implications of faster droughts on risk management and challenges the research of drought hazard prediction.

 

 

[1] Mengel, M., et al. “ATTRICI v1.1 – counterfactual climate for impact attribution.” Geosci. Model Dev., 14, 5269–5284.

[2] WU, Jiefeng, et al. Hydrological drought instantaneous propagation speed based on the variable motion relationship of speed‐time process. Water Resources Research, 2018, 54.11: 9549-9565.

 

Acknowledgements: “Co-funded by the ERASMUS+ Programme of the European Union” (Contract number: 101004049 — EURECA-PRO — EAC-A02-2019 / EAC-A02-2019-1).