A multidisciplinary team of scientists at the University of British Columbia (Canada), led by Ted Scott, set out to determine how has changed on our planet since the early 1960s.
A study published in Environmental Research Letters confirmed what most people around the world are already feeling. Summer, which is heavily influenced by human-caused , now arrives earlier, lasts longer, and is hotter than it used to be.
What scientists discovered about how summer is changing
The researchers analyzed periods when exceeded the historically typical threshold for a given city on the hottest days of the year. They set that threshold using data from 1961–1990. The scientists examined trends not only in those decades but also in the ones that followed.
The team modeled summer changes using several representative cities around the world (taking climate change into account). They found that the length of summer — not the calendar dates but the period during which summer conditions persist — is increasing by an average of six days per decade.
In Minneapolis, Minnesota — Ted Scott’s hometown — the change amounted to nine days, The Guardian reported.
The team’s analysis shows that, in Toronto, Canada, summer is increasing by a little more than eight days every ten years. In Paris, France, and Reykjavik, Iceland, the increase is 7.2 days. In Sydney, it’s as much as 15 days.
Sydney’s summer is breaking records
This Australian city turned out to be the most extreme example. During the summer period, temperatures in Sydney rose two and a half times faster than the global average.
Data showed that, typically, summer in Sydney
- in 1961–1970 began on January 6 and ended on March 9
- in 1991–2000 began on December 21 and ended on March 12
- in 2014–2023 began on November 27 and ended on March 28
So, during the most recently analyzed decade, Sydney’s summer began almost a full month earlier.
“So Sydney’s summer now lasts about 125–130 days, whereas in the 1960s it was half as long — about 65 days,” Ted Scott said.
The study also showed that seasonal shifts are becoming sharper. Summer conditions are arriving suddenly. The gradual warming of the past may be over.
“And it’s all because we keep burning fossil fuels and emitting carbon dioxide,” Andrew Watkins, an adjunct professor at the School of Earth, Atmosphere and Environment at Monash University (Australia), said.
Photo: Unsplash
