3 ms·

>This seems extremely overblown. I used the wiggle word of potential because the severity of these feedback loops is debatable, but I don't think it's overblow

>This seems extremely overblown. I used the wiggle word of potential because the severity of these feedback loops is debatable, but I don't think it's overblown at all. If a tipping point does in fact exist and we pass it, it means we will be on an irreversible course to indefinite warming of the planet. To make matters worse, a positive feedback loop implies an exponential growth, unless some sort of negative feedback loop kicks in to counter it. It is estimated that we have warmed the planet by 1.21C so far (as of 2021) since pre-industrial era[1]. In the worst case scenario (RCP8.5), temperatures will reach 2.5-4.9C by 2100[2]. It's worth pointing out the impact of temperature increase is exponential as well, i.e. 2C global temperature increase will make severe weather events 4 times more frequent than a 1.5C global temperature increase. Some studies estimate that all of earth will be uninhabitable by humans if the global temperature reaches 12C above pre-industrial era[3]. I don't think it's overblown to say this is possible within the next few hundreds of years, especially if these feedback loops turn out to kick in and start rapidly pumping more CO2 into the atmosphere than we do. [1] http://berkeleyearth.org/global-temperature-report-for-2021/ http://berkeleyearth.org/global-temperature-report-for-2021/ [2]: https://www.ipcc.ch/site/assets/uploads/sites/3/2019/11/SROCC_FD_TS_Final.pdf https://www.ipcc.ch/site/assets/uploads/sites/3/2019/11/SROC... [3]: https://www.sciencefocus.com/planet-earth/how-hot-could-earth-get-before-its-uninhabitable-for-humans/ https://www.sciencefocus.com/planet-earth/how-hot-could-eart...

midoridensha 4y ago
I'm of course quibbling over the definition of "uninhabitable", but again this seems overblown. I concede you're referring to the habitability of Earth by humans, rather than just extremophiles. But still, even with a worst-case scenario, I don't see how this would ever make the Earth completely uninhabitable to humans. Would it make it impossible to sustain billions of humans? Sure, unless they develop some really interesting tech. But I don't see how a mere 12C rise in temperature (or even double that) would make it impossible for humans to survive. Life would probably greatly resemble a Max Max movie, but still, that's different from "uninhabitable". "Uninhabitable" means there's no way for humans to survive at all.
- lordswork 4y ago
  >But I don't see how a mere 12C rise in temperature (or even double that) would make it impossible for humans to survive. Where is your intuition for this coming from? Note that 12C rise in global temperature is a very different statement than 12C rise in average temperature of where you live. The temperature increase is applied non-uniformly. Also, the volatility in weather scales exponentially with global temperature increase. For example, 1.5C to 2C rise is expected to create 4 times more extreme weather events globally. >Life would probably greatly resemble a Max Max movie We don't need a fictional movie to see what life would be like. We are seeing glimpses of it already with these mega weather events hitting areas with a higher risk index such as the recent flooding in Pakistan that resulted in 33 million people impacted, ~600K people displaced, ~2,000 people dead, and ~10 billion USD in damages: https://en.wikipedia.org/wiki/2022_Pakistan_floods https://en.wikipedia.org/wiki/2022_Pakistan_floods update to comment: I just saw this article this morning -- a new study on those tipping points I mentioned earlier in our discussion: https://www.theguardian.com/environment/2022/sep/08/world-on-brink-five-climate-tipping-points-study-finds https://www.theguardian.com/environment/2022/sep/08/world-on...
  - midoridensha 4y ago
    2000 people dead is bad of course, but there's 7.5 billion people on the planet right now, so it's not much really. I really feel like you're looking at a worst-case scenario, comparing it to living in modern civilization, and concluding that modern civilization can't possibly survive such an extreme climactic change, and then concluding that humans will go extinct. I'm sorry, but that simply does not logically follow. Civilization can be destroyed, but this is quite different from all humans going extinct. The Mad Max movies may be fictional, but they do show how humans are able to survive in very extreme conditions, which has been proven countless times in history by humans who really did survive in extreme conditions (go talk to the Innuit for instance). Will 7.5B humans survive in such conditions? Obviously not. Will a few thousand? Quite possibly. It was only a very small number of humans that crossed the land bridge from Africa to the Middle East to populate the rest of the world.
    - 4y ago

midoridensha 4y ago

I'm of course quibbling over the definition of "uninhabitable", but again this seems overblown. I concede you're referring to the habitability of Earth by humans, rather than just extremophiles. But still, even with a worst-case scenario, I don't see how this would ever make the Earth completely uninhabitable to humans. Would it make it impossible to sustain billions of humans? Sure, unless they develop some really interesting tech. But I don't see how a mere 12C rise in temperature (or even double that) would make it impossible for humans to survive. Life would probably greatly resemble a Max Max movie, but still, that's different from "uninhabitable". "Uninhabitable" means there's no way for humans to survive at all.

lordswork 4y ago
>But I don't see how a mere 12C rise in temperature (or even double that) would make it impossible for humans to survive. Where is your intuition for this coming from? Note that 12C rise in global temperature is a very different statement than 12C rise in average temperature of where you live. The temperature increase is applied non-uniformly. Also, the volatility in weather scales exponentially with global temperature increase. For example, 1.5C to 2C rise is expected to create 4 times more extreme weather events globally. >Life would probably greatly resemble a Max Max movie We don't need a fictional movie to see what life would be like. We are seeing glimpses of it already with these mega weather events hitting areas with a higher risk index such as the recent flooding in Pakistan that resulted in 33 million people impacted, ~600K people displaced, ~2,000 people dead, and ~10 billion USD in damages: https://en.wikipedia.org/wiki/2022_Pakistan_floods https://en.wikipedia.org/wiki/2022_Pakistan_floods update to comment: I just saw this article this morning -- a new study on those tipping points I mentioned earlier in our discussion: https://www.theguardian.com/environment/2022/sep/08/world-on-brink-five-climate-tipping-points-study-finds https://www.theguardian.com/environment/2022/sep/08/world-on...
- midoridensha 4y ago
  2000 people dead is bad of course, but there's 7.5 billion people on the planet right now, so it's not much really. I really feel like you're looking at a worst-case scenario, comparing it to living in modern civilization, and concluding that modern civilization can't possibly survive such an extreme climactic change, and then concluding that humans will go extinct. I'm sorry, but that simply does not logically follow. Civilization can be destroyed, but this is quite different from all humans going extinct. The Mad Max movies may be fictional, but they do show how humans are able to survive in very extreme conditions, which has been proven countless times in history by humans who really did survive in extreme conditions (go talk to the Innuit for instance). Will 7.5B humans survive in such conditions? Obviously not. Will a few thousand? Quite possibly. It was only a very small number of humans that crossed the land bridge from Africa to the Middle East to populate the rest of the world.
  - 4y ago