What can ancient climate tell us about modern droughts?

Climate change is reshaping the global water cycle, disrupting rainfall patterns and putting growing pressure on cities and ecosystems. Some regions are grappling with heavier rainfall and flooding, while others face prolonged droughts that threaten public health, disrupt economies and increase the risk of political instability. In one recent example, a years-long drought between 2015 and 2020 brought Cape Town, South Africa, to the brink of running out of water—a moment officials dubbed "Day Zero."