Details

Autor(en) / Beteiligte

• Pascale, Salvatore
• Kapnick, Sarah B.
• Delworth, Thomas L.
• Cooke, William F.

Titel

Increasing risk of another Cape Town “Day Zero” drought in the 21st century

Ist Teil von

• Proceedings of the National Academy of Sciences - PNAS, 2020-11, Vol.117 (47), p.29495-29503

Ort / Verlag

United States: National Academy of Sciences

Erscheinungsjahr

2020

Quelle

EZB-FREE-00999 freely available EZB journals

Beschreibungen/Notizen

• Three consecutive dry winters (2015–2017) in southwestern South Africa (SSA) resulted in the Cape Town “Day Zero” drought in early 2018. The contribution of anthropogenic global warming to this prolonged rainfall deficit has previously been evaluated through observations and climate models. However, model adequacy and insufficient horizontal resolution make it difficult to precisely quantify the changing likelihood of extreme droughts, given the small regional scale. Here, we use a high-resolution large ensemble to estimate the contribution of anthropogenic climate change to the probability of occurrence of multiyear SSA rainfall deficits in past and future decades. We find that anthropogenic climate change increased the likelihood of the 2015–2017 rainfall deficit by a factor of five to six. The probability of such an event will increase from 0.7 to 25% by the year 2100 under an intermediate-emission scenario (Shared Socioeconomic Pathway 2-4.5 [SSP2-4.5]) and to 80% under a high-emission scenario (SSP5-8.5). These results highlight the strong sensitivity of the drought risk in SSA to future anthropogenic emissions.