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The hard times are already upon us and will only be getting worse within our lifetimes. The consensus is that things will be somewhere between really bad and ca

The hard times are already upon us and will only be getting worse within our lifetimes. The consensus is that things will be somewhere between really bad and catastrophic by 2100, depending on how much we reduce CO2e emissions and implement mitigation strategies globally[1]. So far, the lack of progress on reducing our dependence on oil and gas globally suggests we're on track for a more catastrophic scenario, i.e. somewhere between RCP4.5 and RCP 8.5 [2]. Also, there are many potential feedback loops that may put us on an irreversible course towards the planet becoming uninhabitable in the future [3]. There is still a lot of scientific debate about when we will hit these feedback loops and how significant they will be. Where you stand on this issue is often what separates the doomer climate scientists that think we're passed these tipping points from the optimist climate scientists that think it's still avoidable or the feedback loops will not be too significant. Most climate modeling focuses on the years of 2050 and 2100. What happens if we continue to make little progress by 2050 or 2100? As long as CO2e emissions are above net zero, warming will continue, and the effects will continue to get worse. Even if we do level-off CO2e emissions and stabilize at 2°C or 3°C, that temperature and all the extreme events, places that are no longer inhabitable, and lower crop yields that come with it will become the new norm, making life a lot harsher for future generations. [1]: https://www.ipcc.ch/report/ar6/wg2/ https://www.ipcc.ch/report/ar6/wg2/ [2]: https://link.springer.com/article/10.1007/s10584-011-0149-y https://link.springer.com/article/10.1007/s10584-011-0149-y [3]: https://en.wikipedia.org/wiki/Climate_change_feedback https://en.wikipedia.org/wiki/Climate_change_feedback

midoridensha 4y ago
>Also, there are many potential feedback loops that may put us on an irreversible course towards the planet becoming uninhabitable in the future This seems extremely overblown. The idea that the Earth will become "uninhabitable" seems ridiculous at best: the Earth has been "habitable" for literally billions of years, even when the climate was vastly different than it is now. And if you mean "habitable by humans" rather than "habitable by any lifeform", humans in particular have adapted to an extremely wide range of climates, from frozen tundra to middle eastern deserts. Perhaps you mean "habitable by 7-10 billion humans with today's civilization and level of technology and standard of living"? It's hard to imagine the Earth ever becoming completely uninhabitable by humans; someone will figure out a way to survive, no matter the catastrophe. But it won't be comfortable like today, and the planet probably won't support today's population levels.
- lordswork 4y ago
  >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.

midoridensha 4y ago

>Also, there are many potential feedback loops that may put us on an irreversible course towards the planet becoming uninhabitable in the future This seems extremely overblown. The idea that the Earth will become "uninhabitable" seems ridiculous at best: the Earth has been "habitable" for literally billions of years, even when the climate was vastly different than it is now. And if you mean "habitable by humans" rather than "habitable by any lifeform", humans in particular have adapted to an extremely wide range of climates, from frozen tundra to middle eastern deserts. Perhaps you mean "habitable by 7-10 billion humans with today's civilization and level of technology and standard of living"? It's hard to imagine the Earth ever becoming completely uninhabitable by humans; someone will figure out a way to survive, no matter the catastrophe. But it won't be comfortable like today, and the planet probably won't support today's population levels.

lordswork 4y ago
>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.