4 ms·

We tend to low-ball the predictions from the models for political reasons and not to sound too alarmist, but we get more and more data showing that the numbers

We tend to low-ball the predictions from the models for political reasons and not to sound too alarmist, but we get more and more data showing that the numbers we use are severely underestimated. 1.5°C was always a pipe dream, but it looks like even 2°C or 2.5°C are all but inevitable, just because of the stuff that’s already in the atmosphere. Yeah, there is little to be optimistic about.

TazeTSchnitzel 5y ago
What really spooks me is: how much of the baked-in warming, and warming we are unlikely to avoid, is going to set off irreversible tipping points?
- ljf 5y ago
  This - the tipping point where a glacier melt is sped up, and then exposes peat and releases more co2 etc etc - there are so many little tipping points that we just don't know about. Maybe easy alone would have a minor impact, but cumulatively the impacts may be huge. A lot will also depend on the state of society in general when the things get tough, will extreme heat or extreme rain come during a war, or economic downturn, or in a pandemic?
rayiner 5y ago
Okay but what does 2.7C really mean in terms of aggregate effects? Quantify it relative to something concrete.
- smaddox 5y ago
  Global average temperature was 4C lower than pre-industrial levels during the last ice age. New York was a kilometer under ice.
  - tomjen3 5y ago
    Based on that, it would be a good thing and we should work to increase global warming so that our safety margin gets bigger.
    - ceejayoz 5y ago
      If "ice" and "no ice" were the only two possible scenarios, sure. Unfortunately, it's entirely possible to go too far in the other direction. https://en.wikipedia.org/wiki/Wet-bulb_temperature https://en.wikipedia.org/wiki/Wet-bulb_temperature > Even heat-adapted people cannot carry out normal outdoor activities past a wet-bulb temperature of 32 °C (90 °F), equivalent to a heat index of 55 °C (130 °F). The theoretical limit to human survival for more than a few hours in the shade, even with unlimited water, is 35 °C (95 °F) – theoretically equivalent to a heat index of 70 °C (160 °F), though the heat index does not go that high. > A heat wave in August 2015 saw temperatures of 48.6 °C (119.5 °F) and a dew point of 29.5 °C (85.1 °F) at Samawah, Iraq, and 114.8 °F (46.0 °C) with a dew point of 89.6 °F (32.0 °C) in Bandar-e Mahshahr, Iran. This implied wet-bulb temperatures of about 33.5 °C (92.3 °F) and 34.7 °C (94.5 °F) respectively. The government urged residents to stay out of the sun and drink plenty of water. Hit 35 °C wet bulb somewhere heavily populated like Bangladesh for a day and you're looking at significant casualties.
    - deleted 5y ago
      [deleted]
    - scarmig 5y ago
      The appropriate comparison: imagine you had NYC in Doggerland in 10000 BCE, and the ice age ended in ~100 years.
  - Tepix 5y ago
    I don't think New York was there at the time.
- Tepix 5y ago
  2.7°C is the world wide average. It will be a lot more in places. This would mean 200 million refugees compared to 44 million refugees that we can expect when we manage to pull of a climate-friendly scenario (which looks rather unlikely at the moment).(1) I suggest you have a look at the sixth IPCC assessment report released in August https://www.ipcc.ch/report/ar6/wg1/ https://www.ipcc.ch/report/ar6/wg1/ especially chapter 12 of the full report. (1) https://www.pri.org/stories/2021-09-13/report-climate-change-could-move-200-million-people-2050 https://www.pri.org/stories/2021-09-13/report-climate-change...
  - Zababa 5y ago
    It really says a lot that the figure people give is instantly the number of refugees.
    - Sharlin 5y ago
      It's a good metric to give because the whole concept of climate refugees seems to be something people often haven't even considered. We seem to have grown so used to this modern sedentary lifestyle that we forget that migration is what humans do, what we have adapted to do, when conditions become inhospitable. Especially if the alternative is to give up and die.
      - Zababa 5y ago
        I think that anyone that lives in Europe has already considered this, especially after the waves of "Syrian refugees". People in North America may not think about it too much as crossing the Atlantic is a bit more involved than crossing the Mediterranean sea.
        Teknoman117 5y ago
        As far as North America goes, while I can't speak for Canada, I know the US is wholly unprepared for massive migration from other regions. Look at how we view immigrants right now. The last administration's brand was "build a wall and keep them out". These are just the people who are running from oppressive governments or cartels - when global climate change makes the equatorial regions less and less inhabitable from pure heat, apocalyptic storms, desertification, severe humidity, etc. all of Central America is headed northward towards the US and Canada, or south towards Argentina and southern Chile. Admittedly, we're only going to be dealing with 550 million people being added to our combined 360 million people, as compared to Northern Asia and Europe, which will be dealing with literally the rest of the human species. The first wave is going to be all the pacific islanders looking to move when the fish stocks collapse in the 2050s to places like China, Japan, and Australia (while it hasn't completely overheated yet). The next two centuries are going to suck unless we actually do something about it. Presumably after that we'll have taken so much of a beating that some new equilibrium will have been achieved.
- kergonath 5y ago
  More extreme events, more frequently, causing more damage both in economic and human terms, mostly. Also, some places uninhabitable around South and South-East Asia, leading to lots of millions of refugees. It is very difficult to quantify accurately, because this is unprecedented in the history of the planet, never mind the history of the human race.
- dredmorbius 5y ago
  http://wondermark.com/1k62/ http://wondermark.com/1k62/

TazeTSchnitzel 5y ago

What really spooks me is: how much of the baked-in warming, and warming we are unlikely to avoid, is going to set off irreversible tipping points?

ljf 5y ago
This - the tipping point where a glacier melt is sped up, and then exposes peat and releases more co2 etc etc - there are so many little tipping points that we just don't know about. Maybe easy alone would have a minor impact, but cumulatively the impacts may be huge. A lot will also depend on the state of society in general when the things get tough, will extreme heat or extreme rain come during a war, or economic downturn, or in a pandemic?

rayiner 5y ago

Okay but what does 2.7C really mean in terms of aggregate effects? Quantify it relative to something concrete.

smaddox 5y ago
Global average temperature was 4C lower than pre-industrial levels during the last ice age. New York was a kilometer under ice.
- tomjen3 5y ago
  Based on that, it would be a good thing and we should work to increase global warming so that our safety margin gets bigger.
  - ceejayoz 5y ago
    If "ice" and "no ice" were the only two possible scenarios, sure. Unfortunately, it's entirely possible to go too far in the other direction. https://en.wikipedia.org/wiki/Wet-bulb_temperature https://en.wikipedia.org/wiki/Wet-bulb_temperature > Even heat-adapted people cannot carry out normal outdoor activities past a wet-bulb temperature of 32 °C (90 °F), equivalent to a heat index of 55 °C (130 °F). The theoretical limit to human survival for more than a few hours in the shade, even with unlimited water, is 35 °C (95 °F) – theoretically equivalent to a heat index of 70 °C (160 °F), though the heat index does not go that high. > A heat wave in August 2015 saw temperatures of 48.6 °C (119.5 °F) and a dew point of 29.5 °C (85.1 °F) at Samawah, Iraq, and 114.8 °F (46.0 °C) with a dew point of 89.6 °F (32.0 °C) in Bandar-e Mahshahr, Iran. This implied wet-bulb temperatures of about 33.5 °C (92.3 °F) and 34.7 °C (94.5 °F) respectively. The government urged residents to stay out of the sun and drink plenty of water. Hit 35 °C wet bulb somewhere heavily populated like Bangladesh for a day and you're looking at significant casualties.
  - deleted 5y ago
    [deleted]
  - scarmig 5y ago
    The appropriate comparison: imagine you had NYC in Doggerland in 10000 BCE, and the ice age ended in ~100 years.
- Tepix 5y ago
  I don't think New York was there at the time.
Tepix 5y ago
2.7°C is the world wide average. It will be a lot more in places. This would mean 200 million refugees compared to 44 million refugees that we can expect when we manage to pull of a climate-friendly scenario (which looks rather unlikely at the moment).(1) I suggest you have a look at the sixth IPCC assessment report released in August https://www.ipcc.ch/report/ar6/wg1/ https://www.ipcc.ch/report/ar6/wg1/ especially chapter 12 of the full report. (1) https://www.pri.org/stories/2021-09-13/report-climate-change-could-move-200-million-people-2050 https://www.pri.org/stories/2021-09-13/report-climate-change...
- Zababa 5y ago
  It really says a lot that the figure people give is instantly the number of refugees.
  - Sharlin 5y ago
    It's a good metric to give because the whole concept of climate refugees seems to be something people often haven't even considered. We seem to have grown so used to this modern sedentary lifestyle that we forget that migration is what humans do, what we have adapted to do, when conditions become inhospitable. Especially if the alternative is to give up and die.
    - Zababa 5y ago
      I think that anyone that lives in Europe has already considered this, especially after the waves of "Syrian refugees". People in North America may not think about it too much as crossing the Atlantic is a bit more involved than crossing the Mediterranean sea.
      - Teknoman117 5y ago
        As far as North America goes, while I can't speak for Canada, I know the US is wholly unprepared for massive migration from other regions. Look at how we view immigrants right now. The last administration's brand was "build a wall and keep them out". These are just the people who are running from oppressive governments or cartels - when global climate change makes the equatorial regions less and less inhabitable from pure heat, apocalyptic storms, desertification, severe humidity, etc. all of Central America is headed northward towards the US and Canada, or south towards Argentina and southern Chile. Admittedly, we're only going to be dealing with 550 million people being added to our combined 360 million people, as compared to Northern Asia and Europe, which will be dealing with literally the rest of the human species. The first wave is going to be all the pacific islanders looking to move when the fish stocks collapse in the 2050s to places like China, Japan, and Australia (while it hasn't completely overheated yet). The next two centuries are going to suck unless we actually do something about it. Presumably after that we'll have taken so much of a beating that some new equilibrium will have been achieved.
kergonath 5y ago
More extreme events, more frequently, causing more damage both in economic and human terms, mostly. Also, some places uninhabitable around South and South-East Asia, leading to lots of millions of refugees. It is very difficult to quantify accurately, because this is unprecedented in the history of the planet, never mind the history of the human race.
dredmorbius 5y ago
http://wondermark.com/1k62/ http://wondermark.com/1k62/