The 2015 Paris Agreement, which aims to limit global warming to 1.5 degrees Celsius above pre-industrial levels, has already been violated, according to European scientists who found that last summer was the hottest on Earth in 2000 years in the northern hemispheres.
Specifically, new estimates from tree-ring records suggest the summer of 2023 will be 2.07 degrees Celsius warmer than pre-industrial levels; This means that global warming exceeds previous estimates of 1.48 degrees Celsius above the pre-industrial level. The scientists said relatively sparse data on the southern hemisphere, which responds differently to climate change than its northern counterpart, makes it difficult to draw conclusions about the region’s climate over the past two millennia, so their study focused on the northern hemisphere. hemisphere.
But the new discovery came as no surprise to climatologists after the United States, Europe, China and other parts of the world saw record temperatures last summer. It was hot enough to melt Antarctic sea ice, record low temperatures and cause Canada’s worst ever wildfire season, burning an unprecedented 45 million hectares of land.
“I’m not surprised,” Jan Esper, a climate scientist at Johannes Gutenberg University in Germany, told reporters at a briefing. “I’m worried about global warming; it’s one of the biggest threats.”
In addition to global warming caused by greenhouse gas emissions, which are mostly the result of human activities such as burning coal, the record heat in 2023 has been exacerbated by El Niño, a recurring weather pattern associated with higher average temperatures in the Pacific Ocean. Scientists say global warming caused by heat-trapping gases has strengthened El Niño over the past 60 years, affecting weather around the world by increasing already high temperatures and leading to hotter, longer summers with strong heatwaves like those observed last year.
Although weather conditions have now returned to neutral conditions, scientists warn that this summer will likely break records again. April has already become the hottest April on record, after an ocean heatwave continued for the 13th consecutive month, according to the European Union’s Copernicus Climate Change Service.
“It’s clear that we need to do as much as possible, as quickly as possible,” Esper said.
Esper and his team analyzed archival data on year-to-year temperature fluctuations recorded in tree rings, which scientists believe is the only reliable record from the past 2,000 years. By comparing tree-ring records with early instrumental data, scientists say the period from 1850 to 1900, referenced in the 2015 Paris Protocol to define pre-industrial temperatures, was “about a tenth of a degree Celsius colder than thought.” By recalibrating this baseline, which they say was first calculated using rare and sometimes conflicting instrumental data from the 19th century, they found that our planet has warmed by 2.07 degrees Celsius compared to pre-industrial levels, higher than preliminary estimates.
The findings are also consistent with a recent report from the World Meteorological Organization (WMO), which confirmed that 2023 will likely be the hottest year recorded in the last 100,000 years. “The state of the climate in 2023 has given a worrying new meaning to the phrase ‘beyond the charts’,” WMO said in a statement. said.
The temperature difference between historical tree-ring data and instrumental data “fundamentally calls into question the calculation of temperature ranges considered in the 2015 Paris Agreement,” the scientists say. The new findings mean that the target of nearly 200 countries under the agreement to limit global warming to 1.5 degrees Celsius above pre-industrial levels has been “already exceeded”, according to a new study.
“On the one hand, it’s just a technical problem; the warming hasn’t changed, the reality hasn’t changed,” Esper told reporters. But he added that “it’s important to get the right numbers.”
Additional measurements of tree rings from other parts of the world will allow scientists to connect their findings to the deeper past. “There’s a lot of wood out there,” Esper told reporters during a briefing. However, he noted that scientists face difficulties and delays in obtaining permission to take tree samples. “We often cannot get permission or it takes too long, which of course prevents us from creating and updating longer records.”
Source: Port Altele
