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A cat finding shade under a bench on a hot day in July 2023 in Istanbul, Turkiye
too hot
Last summer was the hottest in the northern hemisphere in 2,000 years - yes, 2,000 - study says
“2023 was an exceptionally hot year and this trend will continue unless we dramatically reduce greenhouse gas emissions,” the study’s co-author said.
IF YOU THOUGHT last summer felt hotter than usual, you weren’t wrong.
A new study, published in scientific journal Nature, has found that summer 2023 was the hottest in the northern hemisphere in the last 2,000 years.
The record heat was attributed to climate change and amplified by the El Nino weather phenomenon that drove temperatures up even further.
The Cerberus heatwave, named after a three-headed, monstrous dog in Greek mythology, brought scorching temperatures to Europe last year.
Since then, scientists were able to look at data in tree rings that reveal a wealth of information about climate patterns over the last two millenia and compare the findings to modern temperatures and other historical sources of data.
The study found that summer temperatures in 2023 summer temperatures on land in the northern hemisphere were 2.07 Celsius warmer than in the years 1850-1900, the period used as a baseline to compare the pre-industrial period – before human burning of fossil fuels had a major impact on the planet – to the current climate.
The research went further back using the tree ring data over 2,000 years, as well as approximating the variability in the climate caused by El Nino and its opposite La Nina, which has a cooling effect.
It found that the summer of 2023 exceeded the long-term average from 1AD to 1890 by 2.2 Celsius.
The coldest summer in that period was in 536 AD, according to the study, which was nearly four degrees colder than 2023′s. It was influenced by a large volcanic eruption that chucked aerosols into the atmosphere, temporarily limiting the amount of heat that could reach the earth’s surface from the sun.
Global average temperatures are rising above pre-industrial times largely due to humans burning excessive volumes of fossil fuels.
Greenhouse gases that are emitted as a result, like carbon dioxide, effectively clog up the atmosphere and trap heat close to the earth’s surface instead of allowing it to escape.
The consequences are devastating, causing extreme weather events like heatwaves, droughts, and wildfires but also storms and flooding, as well as causing sea ice to melt and sea levels to rise.
Co-author Professor Ulf Buntgen of Cambridge University’s Department of Geography said that looking at the “long sweep” of history allows us to see “just how dramatic recent global warming is”.
“2023 was an exceptionally hot year and this trend will continue unless we dramatically reduce greenhouse gas emissions,” Professor Buntgen said.
Professor Jan Esper of the Johannes Gutenberg University Mainz in Germany said the climate is changing and the warming in 2023 was “additionally amplified” by El Nino conditions, “so we end up with longer and more severe heat waves and extended periods of drought”.
“When you look at the big picture, it shows just how urgent it is that we reduce greenhouse gas emissions immediately.”
Additional reporting by Press Association
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