After the publication of the report of the Intergovernmental Panel on Climate Change (IPCC) on Monday August 9, the director of the Potsdam Institute for Research on the Effects of Climate Change (Germany), Johan Rockström, warns that we are approaching major tipping points. He identified, in 2009, nine thresholds which cannot be overcome without endangering humanity. Four of those planetary boundaries have now been crossed – climate, biosphere, biodiversity and nutrients – and two are about to be: fresh water and ocean acidification.
What are the main conclusions of this new IPCC report?
This is the most scientifically robust IPCC report: it goes a long way in confirming the global aspect of climate change. He puts forward compelling evidence of the gravity of the situation, confirming not only unequivocally that we are warming the planet, but also indisputably that the frequency and severity of extreme weather events are increasing. Heat waves, droughts, floods are now attributed to man-made climate change with a very high degree of certainty. It is therefore real scientific munitions in favor of urgent action.
“The window is still open, but barely open, to be able to limit warming to a manageable global temperature on Earth. “
It is also the first IPCC report not to exclude tipping points, whether it is the instability of the Antarctic ice sheet or the destabilization of AMOC, the meridian circulation of Atlantic reversal. [la circulation des courants océaniques de l’Atlantique, parmi lesquels le Gulf Stream]. It also shows that the capacity of forests, soils and oceans to absorb CO emissions2 risk of weakening. These sinks have so far absorbed 56% of our anthropogenic emissions.
Have we already passed breaking points?
The IPCC report does not conclude this. My assessment is also that we have not yet crossed a major tipping point. Unfortunately, we have more and more scientific evidence that we are getting closer to it, whether it is the destabilization of the western Antarctic ice cap, AMOC, the Arctic or coral reefs. Does this mean that the entire planet has passed some sort of point of no return? The answer is no.
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