Guy McPherson says that humanity could go extinct already at 1,5 C warming above pre-industrial
The controversial doomer professor Guy McPherson is so radical that he in this recent peer-reviewed article in Earth & Environmental Science Research & Reviews, joins Sam Carana in saying that we've already crossed the 2 C above pre-industrial guardrail in global warming, and he says we did it in March 2020 (Sam Carana believes it to be February 2020, see this article). And he is even more radical than that. He says that:
"This current paper describes a few means by which Earth could lose all habitat for Homo sapiens, a process that is already under way. Human extinction likely was triggered when Earth exceeded 2 C above the 1750 baseline. After all, an “increase of 1.5 degrees is the maximum the planet can tolerate; … at worst, [such a rise in temperature above the 1750 baseline will cause] the extinction of humankind altogether” [11]. In other words, human extinction likely was guaranteed with no further degradation of planetary habitat before Earth crossed 2 C above the 1750 baseline in March, 2020."
11. Gaub F (2019) “Global Trends to 2030: Challenges and Choices for Europe,” European Strategy and Policy Analysis System. (I checked the facts, and Gaub never said anything like that. Check for yourself at page 8 and 9. McPherson appears to be misquoting. But what he said tells more about what McPherson himself believes)
So he practically says that humanity could go extinct already at 1,5 C above pre-industrial, and that we now are above 2 C. That's very radical. But remember, he is an environmental professor in conservation biology, so he knows something that we do not, how vulnerable a big loss of habitat is for a species. Humanity has really lost much habitat since the industrial revolution began.
He also writes:
"The first means by which humans could lose habitat was reported by Shakhova et al. (2008) [13]: a burst of methane from beneath the Arctic Ocean. They reported that “up to 50 Gt . . . hydrate storage as highly possible for abrupt release at any time.” Such a rapid burst of methane into the atmosphere would cause an abrupt rise in global-average temperature far too rapid for organisms to adapt. Methane is more than 100 times more powerful than carbon dioxide as a greenhouse gas, and the abrupt release of even half the 50 Gt concluded by Shakhova and colleagues would cause loss of habitat for humans within a matter of months. Shakhova et al. (2008) did not indicate that an ice-free Arctic was required for such a release of methane [13]."
13. Shakhova N, Semiletov I, Salyuk A, Kosmach D (2008) Anomalies of methane in the atmosphere over the East Siberian shelf: Is there any sign of methane leakage from shallow shelf hydrates? Geophysical Research Abstracts 10.
So already a release of 25 gigaton of methane from the Arctic is enough to cause loss of habitat for humans, and as a result, human extinction, according to McPherson. Remember that according to Arctic ice-expert professor Peter Wadhams there could be a release of 700 gigaton of methane from the Arctic at any time during the next few years. See this article. These are very radical views.
