The 2nd edition of the IPCC Climate Change Report (AR6)
(Sustainabilityenvironment.com) – “Almost half of the world’s population lives in areas at risk, now. Nearly half of humanity is living in the danger zone – now. Many ecosystems are at the point of no return – now. Unchecked carbon pollution is forcing the world’s most vulnerable on a frog march to destruction – now. The facts are undeniable”. Climate change is here now, and it affects indiscriminately. And it will do even more in the future. With these words, the UN Secretary-General, Antonio Guterres, presents the latest IPCC climate change report published today.
This is the second part of the 6th Assessment Report (AR6), the periodic update of the report that summarizes the state of the art of global climate science and gives guidelines for political action. This chapter of the IPCC climate change report focuses on the impact of global warming on humans and ecosystems and related upheavals.
And it indicates which strategies to follow and we cannot be found wanting and adapting to the new reality that we are living. The summary for politicians has been filed down in the last 2 weeks as tensions for the Russian invasion of Ukraine deepened, an event that many fear will slow down climate action. So far, however, the shock wave of the conflict has not touched the IPCC, with the Russian head of delegation publicly apologizing (of course only for oneself) on behalf of all Russians who were unable to prevent the event.
The limits of adaptation
Most of the changes triggered on Earth by man-made climate change are now simply irreversible. It does not mean that there is no more hope: with efforts to keep the global temperature within 1.5 degrees, the IPCC confirms that you can partly avoid the most devastating impacts of climate change.
But there are limits. They are the “limits of adaptation“, as defined by the IPCC report on climate change dividing them into two groups. On the one hand, the “soft” ones. Limits that can be circumvented, overcome, and modified. They are those who depend on human action: political barriers, economic and financial setbacks, the will to change. In many cases from a technical point of view it is still possible to use very effective adaptation strategies, explain to the authors; what is missing is precisely the clear will to change.
On the other hand, the “hard” limits: we cannot always adapt, we have biological limits that we cannot go beyond. The human body can only withstand a certain amount of heat, for example. As much as the most vulnerable islands prepare themselves, the rise in sea levels will overwhelm them, as this is an irreversible phenomenon for the next few centuries, regardless of what we do today.
What happens if we exceed 1.5 degrees (even if for a short time)
The latest IPCC report on climate change launches a real ultimatum on this point: the 1.5°C threshold is the decisive turning point for adaptation limits. Beyond this amount of global warming, glaciers and freshwater reserves will decrease at a rate that will force billions of people to become water insecure. Agriculture will disappear from some areas of the planet already with an increase of 2 ºC.
But even a hypothesis considered very probably today, namely the temporary overrun of 1.5 degrees, will have deleterious effects. For the UN Intergovernmental Panel on Climate Change, staying for a couple of decades beyond this threshold will make many of the ongoing processes “irreversible“.
“It’s worse than expected,” says the IPCC climate change report
This already has repercussions on humans and ecosystems. The situation today, the authors write, is worse than the forecast. The threat to humans comes mainly from climatic extremes. Floods and heat waves are already having greater than expected impacts, and have exceeded the ability of many populations to adapt to this “new normality“. Africa, Central and South Asia and Latin America are the most affected regions.
The IPCC climate change report states that within the next few decades, no matter how much we reduce global greenhouse gas emissions, at least 1 billion people will be at risk of extreme events in coastal areas. And if temperatures reach 1.7-1.8, then half of the human population will be exposed to periods of potentially lethal heat and humidity. At that point, however, 14% of living species will be at a very high risk of extinction. But for ecosystems that are already considered vulnerable, the probability of extinction doubles to 2C and becomes 10 times greater with global warming of 3C.
Technology as a solution?
In the summary for politicians, the chapter on possible solutions tries to put some firm points. The IPCC warns against relying too much on technology to solve the climate crisis. Both geoengineering and technologies such as the direct capture of CO2 from the air, the report says, can have counterproductive effects. The recipe is instead a “climate-resilient development”, which goes from rethinking cities to adapt them to heat, flood risk and water availability, from reducing emissions while ensuring the liveability of some areas, and actions that prioritize justice and address gender and income inequalities.
Read the IPCC report here