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The increase of water risks in South Africa

In 2018, due to years of “zero-day” droughts that depleted its reservoirs, Cape Town, South Africa’s second most populous city, almost ran out of water. Since then, researchers at Stanford University have determined that climate change has increased the likelihood of such extreme droughts by 5 to 6 times and warned that more zero-day events may occur in areas with similar climates in the future.

A better understanding of possible surface temperature and precipitation trends in South Africa and other dry-populated areas of the world in the coming decades can promote science-based climate mitigation and adaptation measures aimed at reducing the risk of future zero-day events. To this end, researchers from the Massachusetts Institute of Technology’s Global Change Science and Policy Project, the International Food Policy Research Institute, and CGI​​AR have simulated and predicted seasonal changes in surface temperature and precipitation in the 21st century in South Africa. These predictions are systematic and comprehensive. Explain the uncertainty of how the earth and socio-economic systems work and co-evolve. In a study published in the journal Climate Change, these predictions show how temperature and precipitation in three subnational regions—Western, Central, and Eastern South Africa—may happen under a broad global climate mitigation policy scenario.

In a business-as-usual global climate policy scenario where no emissions or climate targets have been set or met, projections show that for all three regions, there is a more than 50% chance that the mid-century temperature will triple in the past year.

The current climate change range.

However, through more aggressive climate targets, the risk of rising temperatures in the middle of these centuries was effectively eliminated. Business-as-usual forecasts indicate that the risk of a decrease in precipitation in western and central South Africa is three to four times the risk of an increase in precipitation. According to the global climate mitigation policy that aims to control global warming within 1.5 degrees Celsius by 2100, the risk of precipitation changes in South Africa at the end of this century (2065-74) is similar to the risk in the 2030s—as—the usual scenario.

Under the business-as-usual scenario, the risk of a substantial reduction in precipitation throughout the century has continued to rise, which shows that people are increasingly dependent and pressured on extensive water-saving measures formulated after the zero-day drought. However, the 1.5 degrees Celsius global climate mitigation policy will postpone these risks for 30 years, giving South Africa sufficient time to prepare for and adapt to these risks.

C. Adam Schlosser, lead author of the study and deputy director of MIT Joint Programs, said: “Our analysis provides risk-based evidence of the benefits of climate mitigation policies and the inevitable climate impacts that need to be addressed through adaptive measures. ” Global action to limit anthropogenic warming can give South Africa enough time to ensure sufficient water supplies to maintain its population. Otherwise, it is expected that climate change in the middle of the next decade will likely make zero-day conditions more common. ”


With information from: https://phys.org/news/2021-11-scientists-south-africa-century.html


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