It is too bad those posts about the tundras being at the tipping point of methane self release from 2009 were lost. I asked admin about it and they were irretrievable. I only found one left on google some time back.
PETM was such an event, geologically. There was a period of over 10,000 years of increased vulcanism which gradually (much slower than today), drove the atmospheric CO2 levels higher. Of course, much of it was mitigated by the high atmospheric aerosols amount. With the number of volcanic events, it is assumed there were other seismic events that were increased. It is a good conjecture that a large oceanic earthquake caused a huge undersea slide to a clathrate rich area, causing an explosive release of massive amounts of methane.
Either that, or the settling out of particulates led to warmer oceans and arctic tundras which both eventually released all their methane hydrates through temperature gain.
The 2009 Norwegian oceanic results showed it vaporizing even at +1*F, but +2*F is where the vaporization becomes rapid. There is ocean bottom evidence of some clathrate fields explosive releases from seaquakes, but that is nothing compared to if the entire ocean warms up 2*F. The effect would be 1,200 feet, then deeper deposits as they warmed. The tundra releases are much greater than the present atmospheric carbon, and the oceans similar. The oceans take about 1,000 years to warm that much, or more. Still, the process today, in the Anthropocene Epoch, is at least ten times the rate of PETM.
That is where the adaptability issue comes in. The vast majority of species can not adapt to PETM type conditions in that rapid a time frame. PETM caused a species loss of 30% in ten times the time. With the already high background extinction level from human activities (considered an ELE by Leakey), this event is estimated to be up to a 90% species loss. Some articles I read estimated 80%. This is still greater than the estimated 75% species loss of the Yucatan asteroid event.
The possibility of tundra methane self release and its consequences are ignored by many climatologists and denialists. Either they ignore something so horrible or dismiss it out of lack of knowledge. Certainly even a 2*C AGW is bad enough on crop production, and extreme weather destruction. The fact is that the 2*C is also over the amount needed to cause tundra, followed by oceanic, methane self release, AETM and ELE completion.
I have written a lot about the population crash of 2050 or before. That is a bad thing, too. I think it is too late to stop. This ELE is far worse, and something we MAY be able to stop with quick sufficient action. Back in 2006, we were given 10 years to go to massive fossil fuel burning reduction. Then later, by 2020. I have read where this is still only a 50% probability of success. It would have been better odds if action was taken back when the stopping of ozone depleting chemicals was done.
You can argue all you want and put your head in the sand about what humanity is doing to the long term viability of our biosphere. Time is still running out until the hourglass top is empty, just like it did for going to 1 child families to stop the crash.
In a normal crash, the survivors would slowly build back up and stay around long term sustainable level. Passing the tundra methane self release tipping point will lead to a biosphere where humans can not survive, along with 80-90% of the species they depend on.
Humans made it through a bottleneck of several thousand years, back when Toba erupted 76K years ago. This is worse by a long shot.
I can not understand people doing what they have done, seeing we knew some of it on the first Earth Day. Around that time, I got a pass to Saigon with a friend in my unit, to investigate the stinking Black River of Saigon we had to fly high over when we had missions south. I saw houses on poles over the river with ladders/steps leading down. A woman was washing dishes and filling a rice pan, with her young son bathing nearby. Out of a hole in the bottom of the hut fell a turd about 12 feet or so away. They, supposedly intelligent humans, were using the river as a sewer, for drinking, and for washing, and it stunk bad up to 5,000 feet over it.
People all over the world, are doing something similar but not so easily seen or direct. All my proselytizing about overpopulation for over 40 years, AGW for 17 years, and building a solar house, Earthship, and composting and driving a hybrid, with one child now 24, has had no effect at all. The world is heading to hell in a hand basket because of those who deny overpopulation and AGW, et al, and refuse to act out of greed, selfishness, stupidity, or lust.
The time to act is now, to mitigate what will happen. The tipping points may be now, or get crossed, but it is in the self interest of our species to at least try.
"With every decision, think seven generations ahead of the consequences of your actions" Ute rule of life.
“We do not inherit the earth from our ancestors; we borrow it from our children”
― Chief Seattle