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> most of the Earth will be uninhabitable. I find that extremely hard to believe since the dinosaurs evolved on an Earth that was far hotter than what we'll se

> most of the Earth will be uninhabitable. I find that extremely hard to believe since the dinosaurs evolved on an Earth that was far hotter than what we'll see this century (as much as 10°C warmer). Yes, they evolved over millions years from the previous mass extinction event, but the point is that plenty of plants and animals were able to survive in such a warm world. It wasn't mostly inhospitable to life. Also because humans have existed in all sorts of environments from tundras to deserts for tens of thousands of years with stone-aged technology, including ice ages. The latest IPCC reports puts the upper limit of warming under 4°C.

Zircom 4y ago
Uninhabitable as in unable to support modern civilization and population levels, probably in large part due to agriculture no longer being viable due to lack of water or weather related issues I'd assume.
- nradov 4y ago
  That doesn't seem like a good assumption. The fossil record shows a lot of plants growing during previous global warm periods, enough to sustain many herbivores.
  - Zircom 4y ago
    Yeah, grass and bushes and trees and shrubs can, have, and will continue to grow in any but the most extreme conditions sure and those are going to be fine for herbivores who can digest and extract nutrients from them, but for the food crops that we can eat, they need pretty specific climates for us to successfully cultivate them at the scale needed to sustain sizable populations.
richardhod 4y ago
This is an extremely naive and ascientific hot take. Dinosaurs are large creatures of a completely different order, not mammals. The sea ecosystem which had evolved over millions of years to deal with those temperatures is a completely different ecosystem from what we have now. It's not about whether some humans can survive in difficult conditions, it's whether the current ecosystem can survive the unprecedentedly fast and rapid warming. And whether billions of humans will starve
- goatlover 4y ago
  Mammals, reptiles and amphibians existed back then as well, as did a variety of plants. Uninhabitable sounds like most of the Earth turns into Venus, which won't happen. The current ecosystem will undergo change as some species adapt and thrive while others go extinct, migrate or are confined to smaller areas. What this looks like for civilization and to what extent humans can mitigate is debatable. Climate models aren't civilization models.
  - ben_w 4y ago
    There's way too many options to put into even a book, let alone this message[0], but here are some things to consider: • Burning all the known fossil fuels is more than enough to raise CO2 to the level necessary to severely impact (>25% slowdown) human cognition • Although plants like CO2, they are often limited by other things instead • Although we can build personal air supplies for us and greenhouses for plants to optimise each, this is more expensive than not causing the damage in the first place, so not doing the latter implies we will not do the former either • We've messed up local environments more than once, and observed mass migrations as a result; while I'm fine with migrants and confused by those who aren't, I don't let my utopian ideals blind me to the political reality that this will end badly for many innocent people • Quite a lot of property and infrastructure at low elevation and near the coast, combined with a significant risk that the threshold for total loss of various major ice sheets[1] is less than or equal to 4 C [0] written 3h into a post flight cancellation queue for making it the airline's problem that I have work 2000 miles away in 5.5 hours and all the alternative flights they offer are booked out until a week tomorrow, so I apologise for anything weird in this comment [1] I want to say Greenland, but I don't trust myself in this sleep-deprived state
  - notacop31337 4y ago
    Climate models might not be civilisation models, but climate has a very large role in the disruption of civilisation models, look at the Sumerians for evidence of climate/regional degradation and the impact that had on their civilisation. And mitigation is only one part of it, when shortages start, it's not just the climate you have to deal with, it's the humans, who are arguably far more vicious and erratic than any weather or climate.
benpacker 4y ago
It’s mostly about the rate of change. If we went to where we’re going over a hundred thousand years or even a few thousand, ecosystems could adapt, but we’re digging up and burning hundreds of millions of years of carbon in a century
ClumsyPilot 4y ago
> I find that extremely hard to believe failed harvests around the world and famines killing millions are an absolute certainty.
- narcraft 4y ago
  I would like to make a wager
  - forgetfreeman 4y ago
    Would you indeed? I'll take any bet you'd care to place, the San Fernando Valley is sinking feet per year in places due to the volume of water we're pulling out of aquifers right now to support agriculture and the Colorado River doesn't even make it to the Gulf of Mexico anymore for identical reasons. That's the state of play right now at 0 degrees additional warming.
    - narcraft 4y ago
      I would like to make a bet specifically targeting the parent comment's absolute certainty that there will be failed harvests that cause the deaths of millions. When do we expect this to happen? How much time would have to pass without it happening to cause you to reconsider the inevitability of this specific prediction?
      - yawpitch 4y ago
        Ok, $100 USD says that a crop failure resulting in at least 2 million excess deaths happens within the next 20 years, let’s round to <= 31st December, 2042. Of course by then $100 USD will have the purchasing power of ~$10 USD, so it’s not the riskiest bet on my part.
        narcraft 4y ago
        So these will be starvation deaths? I like looking at excess deaths, so we need to look at the base rate of starvation, and I'd like to go per capita, as I expect population to continue to increase substantially and more people to die of all causes year over year as a result. Can we do $10k?
dopidopHN 4y ago
un-habitable for us, as modern human using technology. We're gonna be fine as a specie. Just not like that. I think we should welcome it.
pyrale 4y ago
The temperature isn't as important as the rate of change. > Also because humans have existed in all sorts of environments from tundras to deserts for tens of thousands of years with stone-aged technology The abstract perspective of some humans surviving somehow may not be as comforting as you think.
- bmitc 4y ago
  > The abstract perspective of some humans surviving somehow may not be as comforting as you think. You are right. Humans will likely survive as a species, but not in the numbers and with the comfort we are currently used to.
BlueTemplar 4y ago
We aren't dinosaurs. The end of the abnormally cold climate that we (and other mammals) have enjoyed for the past 2.5 million years (aka Quaternary Ice Age) is likely to cause the Earth to become uninhabitable again to us and most land mammals outside the poles (and poles aren't great with their months-long days and nights). And while this is still unlikely (and we were overdue for a colder, more normal for our Ice Age climate with the end of our interglacial, give or take a few thousand years), we are certainly turning up the heat in an alarming fashion ! (P.S.: the risk comes from the self-reinforcing feedback loops some of which the article describes.)

Zircom 4y ago

Uninhabitable as in unable to support modern civilization and population levels, probably in large part due to agriculture no longer being viable due to lack of water or weather related issues I'd assume.

nradov 4y ago
That doesn't seem like a good assumption. The fossil record shows a lot of plants growing during previous global warm periods, enough to sustain many herbivores.
- Zircom 4y ago
  Yeah, grass and bushes and trees and shrubs can, have, and will continue to grow in any but the most extreme conditions sure and those are going to be fine for herbivores who can digest and extract nutrients from them, but for the food crops that we can eat, they need pretty specific climates for us to successfully cultivate them at the scale needed to sustain sizable populations.

richardhod 4y ago

This is an extremely naive and ascientific hot take. Dinosaurs are large creatures of a completely different order, not mammals. The sea ecosystem which had evolved over millions of years to deal with those temperatures is a completely different ecosystem from what we have now. It's not about whether some humans can survive in difficult conditions, it's whether the current ecosystem can survive the unprecedentedly fast and rapid warming. And whether billions of humans will starve

goatlover 4y ago
Mammals, reptiles and amphibians existed back then as well, as did a variety of plants. Uninhabitable sounds like most of the Earth turns into Venus, which won't happen. The current ecosystem will undergo change as some species adapt and thrive while others go extinct, migrate or are confined to smaller areas. What this looks like for civilization and to what extent humans can mitigate is debatable. Climate models aren't civilization models.
- ben_w 4y ago
  There's way too many options to put into even a book, let alone this message[0], but here are some things to consider: • Burning all the known fossil fuels is more than enough to raise CO2 to the level necessary to severely impact (>25% slowdown) human cognition • Although plants like CO2, they are often limited by other things instead • Although we can build personal air supplies for us and greenhouses for plants to optimise each, this is more expensive than not causing the damage in the first place, so not doing the latter implies we will not do the former either • We've messed up local environments more than once, and observed mass migrations as a result; while I'm fine with migrants and confused by those who aren't, I don't let my utopian ideals blind me to the political reality that this will end badly for many innocent people • Quite a lot of property and infrastructure at low elevation and near the coast, combined with a significant risk that the threshold for total loss of various major ice sheets[1] is less than or equal to 4 C [0] written 3h into a post flight cancellation queue for making it the airline's problem that I have work 2000 miles away in 5.5 hours and all the alternative flights they offer are booked out until a week tomorrow, so I apologise for anything weird in this comment [1] I want to say Greenland, but I don't trust myself in this sleep-deprived state
- notacop31337 4y ago
  Climate models might not be civilisation models, but climate has a very large role in the disruption of civilisation models, look at the Sumerians for evidence of climate/regional degradation and the impact that had on their civilisation. And mitigation is only one part of it, when shortages start, it's not just the climate you have to deal with, it's the humans, who are arguably far more vicious and erratic than any weather or climate.

benpacker 4y ago

It’s mostly about the rate of change. If we went to where we’re going over a hundred thousand years or even a few thousand, ecosystems could adapt, but we’re digging up and burning hundreds of millions of years of carbon in a century

ClumsyPilot 4y ago

> I find that extremely hard to believe failed harvests around the world and famines killing millions are an absolute certainty.

narcraft 4y ago
I would like to make a wager
- forgetfreeman 4y ago
  Would you indeed? I'll take any bet you'd care to place, the San Fernando Valley is sinking feet per year in places due to the volume of water we're pulling out of aquifers right now to support agriculture and the Colorado River doesn't even make it to the Gulf of Mexico anymore for identical reasons. That's the state of play right now at 0 degrees additional warming.
  - narcraft 4y ago
    I would like to make a bet specifically targeting the parent comment's absolute certainty that there will be failed harvests that cause the deaths of millions. When do we expect this to happen? How much time would have to pass without it happening to cause you to reconsider the inevitability of this specific prediction?
    - yawpitch 4y ago
      Ok, $100 USD says that a crop failure resulting in at least 2 million excess deaths happens within the next 20 years, let’s round to <= 31st December, 2042. Of course by then $100 USD will have the purchasing power of ~$10 USD, so it’s not the riskiest bet on my part.
      - narcraft 4y ago
        So these will be starvation deaths? I like looking at excess deaths, so we need to look at the base rate of starvation, and I'd like to go per capita, as I expect population to continue to increase substantially and more people to die of all causes year over year as a result. Can we do $10k?

dopidopHN 4y ago

un-habitable for us, as modern human using technology. We're gonna be fine as a specie. Just not like that. I think we should welcome it.

pyrale 4y ago

The temperature isn't as important as the rate of change. > Also because humans have existed in all sorts of environments from tundras to deserts for tens of thousands of years with stone-aged technology The abstract perspective of some humans surviving somehow may not be as comforting as you think.

bmitc 4y ago
> The abstract perspective of some humans surviving somehow may not be as comforting as you think. You are right. Humans will likely survive as a species, but not in the numbers and with the comfort we are currently used to.

BlueTemplar 4y ago

We aren't dinosaurs. The end of the abnormally cold climate that we (and other mammals) have enjoyed for the past 2.5 million years (aka Quaternary Ice Age) is likely to cause the Earth to become uninhabitable again to us and most land mammals outside the poles (and poles aren't great with their months-long days and nights). And while this is still unlikely (and we were overdue for a colder, more normal for our Ice Age climate with the end of our interglacial, give or take a few thousand years), we are certainly turning up the heat in an alarming fashion ! (P.S.: the risk comes from the self-reinforcing feedback loops some of which the article describes.)