Brian McDonald
Last summer’s sweltering heat broke more than municipal, regional or even national records. In what they call an “alarming discovery”, scientists claim that in the Northern Hemisphere the summer of 2023 was the hottest in 2,000 years.
Global data has already shown that last summer it was the hottest ever recorded. Copernicus, the European Union’s climate change monitoring organization, took this decision. But a new study, published in Nature on Tuesday looked even further back using observed data and reconstructed temperatures from past centuries.
And they found the heat was “unparalleled,” the researchers said.
According to their findings, the Northern Hemisphere experienced the hottest summer in the last 2,000 years, with more than 0.5 degrees Celsius.
Study co-author Ulf Büntgen of the University of Cambridge said in a Press release that last year was “exceptionally hot”, but that the true extent of that heat is visible when we look at the historical record.
“When we look at long history, we can see how dramatic recent global warming is,” Büntgen said, “…and this trend will continue unless we drastically reduce greenhouse gas emissions.”
The study also compared the temperatures of June, July and August 2023 with those of the same months in 536 AD – a year that one historian dubbed “the beginning of the one of the worst times to be aliveif not the worst year”, as it launched the coldest decade in millennia due to massive volcanic eruptions. The difference from that coldest summer to the hottest recent one was 3.93 degrees Celsius.
When it comes to climate change, some people argue that the climate is constantly changing, as seen in the cold period that began in 536 AD. But lead author Jan Esper of Johannes Gutenberg University Mainz in Germany said that, although this is true, it is the continuous greenhouse gas emissions it really makes a difference. The burning of fossil fuels, such as oil and coal, releases a set of gases that trap the Sun’s heat in the atmosphere, continually increasing average temperatures. When this is combined with natural weather events like El Ninowhich occurs when surface temperatures warm in the Pacific, only amplifies the impact.
“We end up with longer, more severe heat waves and prolonged periods of drought,” Esper said. “When we look at the bigger picture, we see how urgent it is to immediately reduce greenhouse gas emissions.”
Experts have long warned that the world needs to take action to try to limit global warming to 1.5 degrees Celsius compared to pre-industrial times. Furthermore, the impacts of rising temperatures, including more frequent and intense droughts, hurricanes and floods, are expected to worsen substantially and drive global migration, food shortages and other problems.
But based on observational records, researchers in this study found that the Northern Hemisphere may have already overcome what. They found that temperatures in the hemisphere last summer were 2.07 degrees Celsius warmer than average temperatures between 1850 and 1900.
“This alarming discovery not only demonstrates that 2023 saw the hottest summer ever recorded across the world [Northern Hemisphere] extratropical climates, but also that the 2015 Paris Agreement to restrict global warming to 1.5 ºC has already been superseded at this limited spatial scale,” says the study.
In their research, the scientists found “inconsistencies” and uncertainties in the initial temperatures that experts have used to monitor temperature rise. These problems are largely due to a lack of records from stations in more remote areas of the world and “inadequately protected thermometers,” the researchers said.
Based on their own studies, they discovered that it was actually cooler in pre-industrial times than previously thought when accounting for prolonged cold spells. Taking this into account, they discovered that the difference in temperatures between that time and last summer was even greater, at 2.20 degrees Celsius.
The researchers noted that their findings are largely based solely on Northern Hemisphere temperatures, as data for the Southern Hemisphere was sparse in the time periods analyzed. They also stated that the region responds differently to climate change because oceans are more prevalent in the southern half of the globe.
Despite the inability to develop complete reconstructions and analyzes of global temperature, the researchers said their study “clearly demonstrates the unparalleled nature of current heat at large spatial scales and reinforces calls for immediate action towards net-zero emissions.”
The article is published as the planet continues to see consecutive months of record heat with deadly consequences. Meteorological experts warned that This summer could be as hot as the lastwith above-normal temperatures expected across most of the U.S.
Li Cohen
