Summers in the Northern Hemisphere could last nearly six months by 2100 if global warming continues unnoticed, according to a recent study examining how climate change affects the pattern and duration of the earth’s seasons.
The study, published last month in the journal Geophysical Research Letters, found that climate change makes summers warmer and longer, while the other three seasons shrink. According to scientists, the irregularities could have serious consequences that could affect human health and agriculture for the environment.
“This is the biological clock for every living thing,” said the study’s lead author, Yuping Guan, a physical oceanographer from the State Key Laboratory of Tropical Oceanography at the Chinese Academy of Sciences. “People are arguing about temperature rises of 2 degrees or 3 degrees, but global warming changing the seasons is something everyone can understand.”
Guan and his colleagues searched daily climate data from 1952 to 2011 to determine the beginning and end of each season in the Northern Hemisphere. They found that summers over the nearly 60 years lasted an average of 78 to 95 days – a difference of about three months.
Winters shortened on average from 76 to 73 days, and the spring and autumn seasons shrank similarly. On average, the spring seasons shrank from 124 days to 115 days, and the fall shortened from 87 days to 82 days.
The scientists used the findings to build a model to project how the seasons may change in the future. They discovered that if the rate of climate change continued unchanged, summers in the Northern Hemisphere could last nearly six months, while winters could last less than two months.
In their study, Guan and his colleagues measured the beginning of summer based on the onset of temperature in the hottest 25 percent during that period. Winter is defined as the onset of temperatures in the coldest 25 percent, they said.
Previous research has shown that climate change has a profound effect on the planet’s seasons – making summers hotter and longer and winters shorter and warmer – but Guan said he was surprised by the dramatic results of his team’s future projections.
“We first looked at 2050 and then calculated the change for 2100, and that was a large number,” Guan said. “For human well-being, I really hoped these results were wrong.”
Changes to the Earth’s seasons pose risks to the environment and human health. Warmer and longer summers, for example, can mean that mosquitoes and other pests that carry diseases can expand and persist in areas where they are not normally found.
“You could get to a point where insects like malaria mosquitoes that are normally kept out of high areas because they can’t survive overnight can survive longer and at higher altitudes,” said Scott Sheridan, a climate scientist at Kent State University. , said. in Ohio, who were not involved in the study.
And because seasons determine the life cycles of plants and animals, climate change can disrupt the ability of species to adapt.
“If seasons start to change, not everything is going to change completely well,” Sheridan said. “If we take an example of flowers coming out of the ground, the flowers may come out, but bees are not yet there to pollinate, or they are already past their peak.”
Climate change is also making seasons ‘more volatile’, Sheridan said, which could have a profound impact on agricultural production. In the US, for example, a “false spring” in March 2012 marked by unreasonably hot weather lured the vegetation outside of dormancy before the schedule, before the temperature dropped again in April.
“Everything kicked into high gear and thought the early summer was coming,” Sheridan said. “In the state of Michigan, large amounts of cherry crop have been lost as a result. Similar things have happened in the South with peach crops.”
Indeed, scientists are eager to understand exactly how climate change will affect the seasons due to the potential impact on food production.
Weston Anderson, a postdoctoral researcher at the International Research Institute for Climate and Society at Columbia University, studies the effect of climate variability on agriculture and food security. Global warming affects not only where certain crops can grow and when not, but also how much they thrive.
“One of the major concerns is how the warming temperature will affect the timing of crop development,” said Anderson, who was not involved in the recent study. “It means how quickly crops mature, and as a result, how much crop yields are affected.”
Although food production issues have a global impact, the Mediterranean region is one area particularly vulnerable to global warming, Anderson said.
“We are already seeing in the Mediterranean that temperatures are rising and the region is getting drier, so less suitable for wheat planting,” he said, adding that places that are already semi-arid are also vulnerable.
Sheridan said the findings of the study help illustrate the severity of climate change by illustrating how people, other animals, plants and the environment are connected to each other.
“The shift of seasons can wreak far more havoc than you think if you realize all the systems put in place for the timing of the seasons,” he said.