That is according to the latest publication of the UN climate panel IPCC, which will be presented today in Geneva. According to scientists who participated in the study, man-made warming is now somewhere between 0.8 and 1.3 degrees compared to the period 1850-1900. The best estimate is 1.07 degrees Celsius.
The IPCC calls it “undeniable” that human emissions of greenhouse gases have warmed the earth (atmosphere, land and oceans). This climate change is leading to various, rapid changes such as glacier decline, sea level rise and, in many places, an increase in precipitation over land.
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Ⓒ Dutch Height / ANP
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Sea level rise
Journalists were probably allowed to see a summary of the Climate Change 2021: the Physical Science study. The IPCC’s full sixth overview report will not be released until next year. However, the United Nations climate panel is now coming up with a ‘state of the climate’ as a warm-up for the climate summit in Glasgow later this year.
According to the latest report, the current CO2 concentration in the atmosphere is higher than in the last two million years. We also have to go back 125,000 years to find the same warm period as the past decade. The sea level has risen faster since 1900 than in the last three thousand years. This increase also appears to have accelerated somewhat in recent decades.
“This report is a reality check,” said Valérie Masson-Delmotte, co-chair of the IPCC Working Group I that prepared the piece. “We now have a much clearer picture of the past, present and future climate. And that’s essential to understand where we’re heading, what we can do, and how we need to prepare.”
heat waves
It is almost certain that one weather extreme occurs more often and is also more intense: heat waves. This applies to almost all regions on Earth. Scientists agree that this is very likely to be linked to greenhouse gas emissions. The frequency and intensity of heavy rainfall has also become more frequent in many areas since 1950. It seems more likely that this is man-made than not man-made.
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For the time being, this link appears to be more difficult to establish with other weather extremes. For example, the number of hurricanes and their size does not seem to change much. Although there are indications that the heaviest specimens would occur slightly more often. With regard to weather conditions that (partly) cause forest fires and floods, scientists do not consider the data and trends to be completely convincing for the time being.
If warming continues, researchers expect that changes in climate will also become more apparent. “The changes we are experiencing will increase with each additional warming,” said Panmao Zhai, co-chair of the committee that prepared the report.
Five scenarios
Predictions for further warming include an increase in precipitation, higher wind peaks during hurricanes and further sea level rise. The IPCC uses five scenarios in the publication, the lowest of which results in a 28 centimeters rise in sea level in 2100, compared to the period 1995-2014. The most extreme scenario predicts a maximum of one meter plus one centimeter in the extreme case.
However, there is also a brake on climate change, according to the IPCC, with a clear hint to the climate summit in Glasgow. If the emissions of CO2 and other greenhouse gases are quickly and structurally curtailed, then global warming does not have to increase much further. The air quality would immediately become better and healthier. But it could take another 20 to 30 years before global temperatures stabilize.
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