Climate change made聽Cape Town鈥檚 recent drought three times聽more likely, climate models suggest.
The water shortage has been so severe that water聽is still limited to no more than 50 litres per person per day. At one point, the city almost had to switch off the water supply.
Cape Town鈥檚 situation was caused聽by three years of below average rainfall, starting in 2015. But, until now, it has been unclear聽exactly how much of a聽role global warming played.
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Local rainfall records do not go back very far, so it is not clear how rainfall patterns have changed. However, the drought also affected much of the western Cape region, including places that have rainfall records going right back to the 1930s.
So a team brought together by initiative ran several climate models to see how well they match the region鈥檚 climate since 1930 鈥� the world as it is. They then ran the best-performing of these models without the 1掳C global warming so far 鈥� the world as it might have been without climate change. Finally, they ran them again in a world that is 2掳C warmer.
The team聽.
鈥淔or an event related to rainfall, three times is huge,鈥� says team member Friederike Otto, a climate scientist at the University of Oxford. 鈥淭his is the first study we have done where we have seen a significant change in drought risk.鈥�
The聽real problem in Cape Town was the failure to adapt to cope with the new climate. As New 杏吧原创 reported earlier this year, the South African government concluded in 2002 that its cities faced water shortages if nothing was done. A 2007 report on Cape Town concluded demand would exceed supply in 2018 鈥� as it did.
This winter has brought above-average rainfall so far and the dams that supply water to the city and nearby farming regions water are half full, after dropping to around a quarter full. The prospect of the taps having to be turned off 鈥� Day Zero 鈥� has therefore receded, but tough water restrictions remain in place.
Local water experts say Cape Town needs to take a range of measures to make its water supply more resilient. These include recycling used water rather than just letting it run out to sea as now happens, and pumping water underground during times of good rainfall for use in dry years. The city is also building desalinisation plants but this is a very expensive source of water.
