The climate crisis is hitting our planet to the point that summers in the Northern Hemisphere could last half the year by 2100, scientists have warned.
This does not mean longer days of lounging in the sun, but dramatic consequences for human health, agriculture and ecology.
While an extended period of mild weather may sound appealing at first, such a significant shift in the seasons can cause massive disruption to ecosystems, which are often well-balanced in timing and temperature.
From protracted heatwaves and wildfires to changing migration patterns affecting the food chain, the study concludes that if global warming continues at its current rate, risks to humanity will only increase over time – and find the changes already place.
Recorded and predicted shifts in Northern Hemisphere seasons. (Wang et al. 2020, Geophysical Research Letters, AGU)
“Summers are getting longer and hotter, while winters are getting shorter and warmer due to global warming,” said physical oceanographer Yuping Guan of the Chinese Academy of Sciences. “More often I read some unusual weather reports, such as false spring or May snow and the like.”
The researchers looked at historical daily climate data from 1952 to 2011, marking the days with the highest 25 percent of temperatures in those years as the summer months and those with the coldest temperatures as the winter months.
The analysis showed that between 1952 and 2011 the summer grew from 78 days to 95 days on average, and the winter from 76 days to 73 days. Spring and autumn also shrank by 9 days and 5 days respectively. While spring and summer have gradually started earlier, autumn and winter start later.
The team then turned to future climate models to predict how these trends would continue through the turn of the century, finding that the Northern Hemisphere could have a summer beginning in early May and ending in mid-October by 2100.
This is a potentially dangerous development for many reasons – for example, it would mean more time with allergenic pollen in the air, and the further spread of disease-carrying tropical mosquitoes, to name just two consequences.
“Numerous studies have already shown that the changing seasons cause significant environmental and health risks,” says Guan.
Based on data collected since 1952, the Mediterranean and Tibetan Plateau have seen the most changes in seasonal cycles, but it is unlikely that any part of the world will be able to escape the domino effects of climate . change.
As temperatures rise, we see the world’s weather patterns change beyond the point of no return – and every weather variation impacts the oceans and the land below.
If we will be able to retreat from the edge of a planet that is warming beyond our control, it is important to gather as much data as possible to inform about the kind of difficult decisions that will be required.
“This is a good overarching starting point for understanding the implications of seasonal changes,” said Kent State University climate scientist Scott Sheridan, who was not involved in the study.
The research is published in Geophysical Research Letters