by The 2015 Paris Agreement, which aims to limit global warming to 1.5 degrees Celsius above pre-industrial levels, has already been breached, according to European scientists who found last summer that Worldthe warmest in the last 2,000 years in the Northern Hemisphere.
Specifically, the new estimates, derived from tree-ring records, show that the summer of 2023 was 2.07 degrees Celsius warmer than pre-industrial levels – meaning the world was warmer. previous estimates, which put the quantity at 1.48 degrees Celsius above pre-industrial levels. Fairly scant information about the Southern Hemisphere, which corresponds variously to climate change than its counterpart in the north, it is difficult to reach conclusions regarding the climate of that region in the last two thousand years, according to the scientists, which is why their study focuses on the Northern Hemisphere.
However, the new result does not surprise climate scientists after what we have seen record setting temperatures sweltering the US, Europe, China and other areas around the world last summer. It was warm enough to thaw the Antarctic sea ice unmatched lows and sparked Canada’s worst wildfire season yet, scorching an unprecedented 45 million hectares of land.
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“I’m not surprised,” Jan Esper, a climate scientist at Johannes Gutenberg University in Germany, told reporters during a press conference. “I’m worried about global warming – it’s one of the biggest threats out there.”
In addition to global warming driven by greenhouse gas emissions, mainly as a result of human activities such as burning coal, the unprecedented heat of 2023 has exacerbated El Nino, which is a recurring weather pattern emerging in the Pacific Ocean that is linked to warmer temperatures on average. Scientists say global warming caused by heat-trapping gases has been strengthening El Niño for the past 60 years, affecting weather around the world by spiking already high temperatures, and leading to hotter and longer summers with severe heat waves such as those seen last year.
Although the weather pattern is easing towards neutral conditions, scientists warn that the records are likely to be broken again this summer. It has already been reported that April is the warm on record after experiencing extreme ocean heat for the 13th month in a row, according to a statement from the European Union Copernicus Climate Change Service.
“It’s so clear that we should do as much as possible, as soon as possible,” Esper said.
Esper and his team analyzed archival data of year-to-year temperature fluctuations recorded in tree-ring width, which scientists say is the only reliable record covering the past 2,000 years. By comparing tree-ring records with early instrumental data, the period 1850 to 1900 referred to in the 2015 Paris protocol to describe pre-industrial temperatures “was several tenths of a degree Celsius cooler than expected, ” say the scientists. By recalibrating that baseline, which they say was originally calculated using sparse, sometimes inconsistent, 19th-century instrumental data, they found that our planet had warmed by 2.07 degrees Celsius compared to pre-industrial levels, which higher than previous estimates had suggested.
The results are also consistent with a recent report from the World Meteorological Organization (WMO) which declared 2023 to be the hottest year on record, possibly in the last 100,000 years. “The state of the climate in 2023 has given dire new meaning to the phrase ‘off the charts,'” WMO said in a statement.
Scientists say the temperature difference between historical tree-ring data and instrumental data “fundamentally calls into question the calculation of the temperature ranges considered in the 2015 Paris Agreement.” The new findings mean the target, sought by nearly 200 countries as part of the agreement to avoid global warming to 1.5 degrees Celsius above pre-industrial levels, is “already in place,” according to the a new study.
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“On the one hand, this is just a technical issue — the warming hasn’t changed, the reality hasn’t changed,” Esper told reporters. But, he said, “it is important to get the right numbers.”
Additional measurements of tree rings from other parts of the world would allow the scientists to put their findings in a more distant context. time. “There’s a lot of wood out there,” Esper told reporters during the briefing. Scientists face a challenge, however, because of difficulties and delays in obtaining permission to sample trees, he noted. “Often, we don’t get the permission, or it takes too long, and of course that hinders the progress of producing longer records and updating the records.”
The staff paper was published on May 14 in the journal Nature.
