[DennisP]

A while back I read Six Degrees by Mark Lynas, who read 3000 peer-reviewed papers on the effects of climate change and summarized them, one chapter per degree, with extensive references.

My takeaway from that book was that three degrees was pretty terrible but life would go on, but at four degrees modern civilization would have a hard time surviving. Go all the way to six and there won't be many humans left on the planet.

I'm not saying we'll get to four degrees in two generations, but at the rate we're going we'll be well on the way, and enough feedbacks will have kicked in by then to make it inevitable.

[gowld]

How is that possible? From the Amazon blurb, it seems that the book talks about what would be destroyed by weather change, but nothing about what would be created. If temperature increases, some current cold areas would be more habitable. If sea levels rise, some inland area would become coastal. These changes would happen over generations, so populations would move. There would be tumult in human and animal life, which is bad but not a novel part of human experience (we've always had hurricanes, tsumanis, earthquakes, and plenty of manmade disasters), but a new equilibrium would be reached. There was once an Ice Age that supported human life! I don't think the overall human environment 6 degrees in the future would be worse than say 200 years ago.

Also, it's been 16 years since the book was published. Have temperatures risen? Have the predictions come to pass?

https://www.amazon.com/Six-Degrees-Future-Hotter-Planet/dp/1...

[DennisP]

We're currently at one degree above preindustrial, and the world looks a lot like he described for that level.

The book was published in 2009 but most of the news since has not been encouraging. A recent book that covers similar ground, also with a lot of references, is Unprecedented by David Ray Griffin; the conclusions are similar. If you want more detail on the geologic evidence, see Storms of My Grandchildren by James Hansen.

You're surely right that there will be things that improve. However, we know from geology and paleontology what's happened in previous major warming periods: mass extinction, and a huge loss of biomass, with most of the survivors clustered around the poles. That doesn't bode well for us.

[antognini]

> However, we know from geology and paleontology what's happened in previous major warming periods: mass extinction, and a huge loss of biomass, with most of the survivors clustered around the poles.

I thought that warming events were generally associated with speciation events, at least on land. (Marine life is a different story.) The last event, the Paleocene-Eocene thermal maximum, coincided with a major speciation event for mammals.