Without efforts to mitigate climate change, a six-month summer will be the new normal by 2100 in the Northern Hemisphere, according to a new study. According to the authors, this will lead to irreversible consequences for agriculture, human health and the environment.
In the 1950s, in the Northern Hemisphere, four seasons followed each other in a predictable and fairly uniform pattern. But now global warming is changing the length and beginning of the seasons.
“Summers are getting longer and hotter, and winters are shorter and warmer due to global warming,” explains Yuping Guan, an oceanographer at the Institute of Oceanology of the Chinese Academy of Sciences. The study is published by Geophysical Research Letters.
The researchers used historical daily climate data from 1952 to 2011 to measure the length and duration of four seasons in the Northern Hemisphere. Scientists then used established models of climate change to predict how the seasons would change in the future.
The results showed that, on average, summer increased from 78 to 95 days, while winter decreased from 76 to 73 days. Spring and autumn also fell from 124 to 115 days and from 87 to 82 days, respectively. Simply put, spring and summer started earlier, and autumn and winter later. The Mediterranean region and the Tibetan Plateau have experienced the biggest changes in their seasonal cycles.
If these trends continue without any climate change mitigation efforts, the researchers predict that winter will last less than two months by 2100, and the transitional spring and fall seasons will also decline.
Seasonal changes can also wreak havoc on agriculture. In addition, with a longer growing season, people will inhale more pollen that causes allergies, and mosquitoes that carry diseases will expand their range northward.