Researchers warn:

Warming above 1.5 degrees would have irreversible consequences

An "overshoot" of the 1.5 degree target could have irreversible consequences for humans and animals.

(Bild: stock.adobe.com/Thongden_studio)

In the Paris climate protection agreement at the end of 2015, the global community set itself the goal of keeping global warming well below two degrees and, if possible, limiting it to 1.5 degrees compared to pre-industrial times. However, many experts believe that this goal can no longer be achieved. Even if the climate could be cooled down again later by removing CO₂ from the atmosphere, much of the damage caused by an "overshooting" of the global average temperature would be irreparable.

Only rapid emission reductions could limit the risks of global warming, emphasize Austrian climate researchers in a recent study. Carl-Friedrich Schleussner and Joeri Rogelj from the International Institute for Applied Systems Analysis (IIASA) in Laxenburg (Lower Austria) and an international team carried out model calculations to determine the consequences of a climate change overshoot, i.e. a global warming overshoot of more than 1.5 degrees Celsius worldwide. They also investigated the chances of the Earth's climate cooling down again afterwards. 

Heatwaves are becoming more frequent and longer.

(Bild: APA/AFP/Kirill KUDRYAVTSEV)

The scientists report that a reduction in temperature may no longer be possible, or at least more difficult than previously assumed. "There is overconfidence that global warming is reversible if net zero greenhouse gas emissions are eventually achieved," Rogelj said at an online press conference on the study.

"There is no guarantee for technologies"
However, it may even be necessary to remove carbon dioxide from the atmosphere for this to happen. Furthermore, there is no guarantee that technologies will be developed that work and are affordable on a global scale. Moreover, such a "temperature overshoot" would have irreversible consequences: Biodiversity would be irrecoverable because more creatures would become extinct. Sea levels would continue to rise even in the event of subsequent cooling. 

The researchers dispel the "idea that if the targets are exceeded in the future, a similar climate condition can be established as if we had done more in time to limit maximum warming to 1.5 degrees Celsius". "However, the consequences of a climate change overshoot are likely to be greater and dirtier than previously assumed."