Repairing the ozone hole didn’t just help reduce the risk of skin cancer; it also reversed unwelcome effects of the climate crisis. Every summer heavy rains bubble up along the southern edge of the Tibetan plateau, but during the 1980s and 1990s the amount of rain increased significantly, raising the risk of flooding and landslides in Nepal and northern India.
Thankfully, since the mid-1990s the trend has reversed. A study shows that the increase and subsequent decrease in Tibetan summer rainfall were linked to changes in ozone levels in the upper atmosphere.
Using long-term measurements of rainfall and stratospheric ozone, researchers were able to model the interactions between ozone and climate and demonstrate that falling ozone levels in the upper atmosphere brought about a cooling effect in the lower stratosphere, which helped to accelerate convection and generate more rain. Their results, published in Geophysical Research Letters, show that the effect was particularly pronounced along the southern edge of the Tibetan plateau.
Rainfall patterns in this region have far-reaching consequences, with 200 million people in Nepal and northern India directly depending on the summer rains. The new model will help improve seasonal forecasts, and better management of water resources for agriculture, hydroelectric power, industry and everyday water needs.
