Terrestrial ecosystems collapse, in particular the Amazon, the Arctic and the Great Barrier Reef. 35% of the Earth’s land surface, where 55% of the world’s population lives, is hit for at least 20 days a year by lethal heatwaves. 30% of the land surface becomes arid: from the Mediterranean to western Asia, from the Middle East to Australia and the south-west of the United States. All lands that become uninhabitable for humans.
The crisis
A colossal water crisis follows, afflicting at least two billion people. Global agriculture collapses, harvests fall by 20%, food prices skyrocket. A huge flow of “climate refugees” begins, at least a billion people.
From this latest upheaval, wars arise between states, which, added to the famines, lead in a more or less variable time to the end of human civilisation as we have known it for about 50,000 years until today.
Compared with the hypothesis of 2100 as the deadline for the end of the world, the Australian study maintains that there are global warming risks not calculated by the Paris Agreement and potentially deadly. The climate change scenarios outlined in 2015 - an increase of three degrees by 2100 - would not take into account the “long term carbon feedback” mechanism by which the planet tends to amplify climate change.
If the “carbon feedback” is taken into account, there is a well-founded possibility of reaching three degrees of warming as early as 2050, rising to five degrees by 2100.
Humans would not live to see them. Many scientists in fact believe that an increase of four degrees would be totally destructive for the planet’s ecosystem.
The problem is the so-called climate “tipping points”. For example, the destruction of the polar ice caps, which leads to a rise in sea level. If these “tipping points” are crossed, climate change will become a non-linear event, hard to predict with the tools currently available.
5%
Global warming would feed itself even without human action, making any possible intervention on emissions too late.
The risk of the end of human civilisation is estimated by scientists such as VeerabhadranRamanathan at 5%. Not much, after all? Not so little, when you think about it. ‘Who would board a plane knowing it has a 5% chance of crashing?’, the scientist declares. Think about it, folks, think about it.
