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Global targets to prevent global warming could be exceeded sooner than expected, experts warned on Monday (September 17th), as gas released by melting permafrost threatened to undermine human efforts to avert a climate disaster.
As part of the current bailout package, outlined in the 2015 Paris Treaty on Climate, countries agreed to limit the global temperature rise to "well below" two degrees Celsius and 1.5 degrees Celsius if possible.
This approach assumes that the treatment of human-caused greenhouse gases, whether by slowing down their emissions or removing them from the atmosphere, will be enough to control global warming.
New research shows that what climate models do not allow are scenarios in which the Earth begins to contribute to the problem.
A team of experts from the Austrian Institute for Applied Systems Analysis said on Monday that it has for the first time included emissions projections from melting permafrost into global patterns of climate change, and the results have raised concerns.
"The release of carbon by permafrost is caused by global warming and will definitely decrease the CO2 budget we can emit while staying below a certain level of global warming," said Thomas Gasser, researcher and author. principal of the study.
While dependence on fossil fuels persists, scientists have calculated that we are likely to "exceed" the Paris temperature targets in the short and medium term.
With only 1 ° C warming above pre-industrial levels, global permafrost is already thawing, albeit slowly.
But the speed of this melting will certainly accelerate as the Earth continues to heat up.
Gasser warned that the surpassing scenario would leave the planet even more vulnerable to permafrost emissions and, in a vicious feedback loop, warm up even more.
In fact, under some models of the study, published in the journal Geoscience of natureWe have already missed the target of 1.5 degrees Celsius due to permafrost emissions.
Cracks and faults in the high arctic permafrost, seen from a helicopter, are probably due to melting. Image courtesy: Wikimedia Commons
"Exceeding is a risky strategy, and going back to lower levels after going over will be extremely difficult," said Gasser. AFP.
"We need to be prepared for the eventuality that we never come back to safer levels of warming."
"Higher temperatures, higher risk"
Methane and CO2 trapped in frozen waste from Russia, Canada and northern Europe are roughly equivalent to 15 years of anthropogenic emissions at current levels.
According to Gasser, the problem with the Paris targets is that they set emission targets based on the assumption that the global temperature and CO2 levels in the atmosphere change step by step.
They therefore allow countries to exceed targets provided that enough carbon can be captured in the air to bring temperatures back to the end of the century.
But permafrost is subject to what scientists call a "tipping point," which means that beyond a certain temperature threshold, it will continue to melt and release greenhouse gases independant of the levels of temperature. 'program.
The models will not take into account these additional greenhouse gases, mainly methane and carbon dioxide.
"Even without talking about the debate about the possibility of capturing CO2 on a large enough scale, there is also the risk that the higher you go, the higher the risk of triggering something that we do not understand is high," Gasser said.
As the world struggles to limit man-made pollution that amplifies the likelihood and intensity of superstormal, heatwaves and deadly droughts, Monday's study will add to fears that the Earth itself may exceed efforts to limit climate change.
The melting sea ice, which creates seawater that absorbs rather than reflects sunlight, and the forest dieback, which would release billions of tons of carbon absorbing CO2, are other tipping points.
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