Hail that forms in bad weather can cause significant damage when the grains hit the ground with high force. Large bad weather can lead to fatalities, destroy crops and damage buildings and were therefore already noted in the old Chinese annals.
Chinese researchers have gone through large amounts of data from the historical books – some 3,000 years old – and studied the numbers.
Can double
In the historical materials, it is only hailstorms that cause damage that are worth reporting, in principle where the hail grains are more than seven millimeters. In the 18th century, before human beings' major impact on the climate began, ten such bad weather occurred per year in China. That figure had increased to 60 in the 1940s. The researchers have tried to take into account the population increase, which increases the number of reports.
Nowadays, the number is up to 300 per year. With the help of AI models, the number is estimated to double by 2072, in a worst-case scenario.
Warmer climate
The conclusion is that climate change drives the long-term trend. A warmer climate provides more energy in the air and increases the availability of moisture, which is required for hail to form. Even natural phenomena linked to the surface water temperature in the Pacific Ocean affect the occurrence.
The challenges "with preventive work against disasters related to hailstorms will increase as the century progresses", the researchers write in the report published in Nature.
