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What are the actual consequences of the globe warming by 2 degrees instead of 1.5 degrees? I feel like I never see it quantified. Like is that the difference be

What are the actual consequences of the globe warming by 2 degrees instead of 1.5 degrees? I feel like I never see it quantified. Like is that the difference between Miami being underwater or not? Is that difference going to cause an extra couple cyclones a year? I'm totally on board with reducing carbon emissions and whatnot, but I don't actually have any idea of the impact. And maybe it is impossible to quantify. I see some people say it is going to make earth uninhabitable, which intuitively seems wrong. But we do see some effects already, so clearly it's not harmless.

bioinformatics 5y ago
Not a mathematician, but >2 degrees instead of 1.5 degrees it's about 0.5 degrees.
pantalaimon 5y ago
My main worry is increasing droughts that will jeopardize our food supply.
- eplanit 5y ago
  Prepare now... pressure your state to build reservoirs.
  - Y_Y 5y ago
    The problem with food reservoirs is that the stuff at the bottom tends to go bad before you can get to it.
    - eplanit 5y ago
      Reservoirs as in lakes for water.
- missedthecue 5y ago
  Climate change has been shown in many studies to increase food production, because carbon is an input to photosynthesis.
stevep98 5y ago
My understanding is that 2 degrees is not that harmful in itself, but it would lead to further uncontrollable runaway increases due to release of methane locked in frozen tundra.
- cableshaft 5y ago
  That, and also we would be reflecting less heat from the sun without the ice, as ice reflects back 90% of the sunlight that hits it, so no ice would lead to even more warming.
ajross 5y ago
The antarctic ice seems already to be melting, so Miami (also the port regions of most cities -- Shanghai has like 15M people living in likely flood zones!) is going under at this stage no matter what we do. Likewise the deep ocean circulation has already begun to collapse, so an anoxic ocean floor seems inevitable. The mass extinction event seems under way already. But the modelling is noisy, so no one can give you serious answers to "how will this affect people" that will meet your demand for precision. But the worst cases are all disastrous. Things like "we can't grow food in south asia to feed the 2-3 billion people there" are very much on the table.
- hackeraccount 5y ago
  How much would a sea wall around Miami or Shanghai cost?
  - nradov 5y ago
    A sea wall around Miami wouldn't help due to the karst substrate; water would flow through the limestone channels under any wall. The main concern with sea level rise in South Florida isn't that the seawater will come in but that rainwater won't drain away. There will have to be a huge investment in pumping systems.
    - missedthecue 5y ago
      That investment is likely cheaper and more feasible than geo-engineering the globe's climate.
- lotsofclaimsbud 5y ago
  You got any citation for this opinion or any other one in your post history? You speak like you're an expert on this subject and others are voting like they trust you, but why? I don't see anything in your profile or history that indicates that you know what you're talking about, and you've provided no evidence here. Your comment sounds like fear mongering to me.
- jjcon 5y ago
fallingfrog 5y ago
My ballpark guess: climate regions will shift north by a few hundred miles. In some places that will mean tundra turns to forest, in other places farmland will turn to desert. Sea levels will also rise by a few feet. But then there will be a couple billion people living in the wrong place; they will have to move across national borders in huge numbers. This is historically linked to political instability and sometimes war. The worst part will be what we do to each other as a result of climate change, rather than the change itself, imho.
- kaybe 5y ago
  This is an interesting paper in this regard: Bastin et al, Understanding climate change from a global analysis of city analogues: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0217592 https://journals.plos.org/plosone/article?id=10.1371/journal... "Even under an optimistic climate scenario (RCP 4.5), we found that 77% of future cities are very likely to experience a climate that is closer to that of another existing city than to its own current climate. In addition, 22% of cities will experience climate conditions that are not currently experienced by any existing major cities. " "We notably predict that Madrid’s climate in 2050 will resemble Marrakech’s climate today, Stockholm will resemble Budapest, London to Barcelona, Moscow to Sofia, Seattle to San Francisco, Tokyo to Changsha." The information might not be new, but the way it is presented is quite tangible, since many people have an understanding of today's conditions in different cities.
  - senkora 5y ago
    Well, I guess I better buy property in Seattle, then.
  - makomk 5y ago
    From what I recall, RCP 4.5 is closer to "status quo" than "optimistic" at least for a while yet.
    - kaybe 5y ago
      I agree. The authors probably had a bad day. Conferences can be depressing. The IPCC reports contain the very basic rock-solid consensus of what can be expected, but while playing around with data and models things can look much scarier.
jjcon 5y ago
> I see some people say it is going to make earth uninhabitable Not even the worst case scenarios from the IPCC show anything even remotely close to ‘uninhabitable earth’ - the people saying that are being even more disingenuous and pseudoscientific than climate deniers. Some fringe regions of the planet may become a lot harder to live in (note that climate change is not uniform, it will affect some places a lot more than others) and of course some coastal areas may experience more flooding but by and large day to day living in the first world will be similar to what it is today even with 2C of warming.
- lotsofpulp 5y ago
  > Some fringe regions of the planet may become a lot harder to live in (note that climate change is not uniform, it will affect some places a lot more than others) and of course some coastal areas may experience more flooding but by and large day to day living in the first world will be similar to what it is today even with 2C of warming. How can this be known at this point? I can certainly imagine changing weather patterns such as monsoon, drought, heat waves, cold snaps, etc not being limited to fringe regions.
  - jjcon 5y ago
    Because we are already seeing it and can model for the future. See the first image in this article and note how some areas have experienced no warming while others a lot as compared to 1900. https://www.climate.gov/news-features/climate-qa/does-global-warming-mean-it’s-warming-everywhere https://www.climate.gov/news-features/climate-qa/does-global...
    - lotsofpulp 5y ago
      But I would not describe the areas experiencing change as “fringe”. Nor do I see a reason to expect the areas not experiencing change to continue not changing.
      - jjcon 5y ago
        ‘Experiencing change’ != ‘a lot harder to live in’ I didn’t say only fringe areas would change
sm0ss117 5y ago
Parts of India might get uninhabitable in the summer in some of the worse case scenarios. Given the population there and the fact they're a nuclear armed state that's a geopolitical powder keg.
hackeraccount 5y ago
In a dynamic system anyone who says they know the consequences with a high degree of certitude is blowing smoke. Oddly the most reasonable course of action is to always paint the worst possible future but it will presumably spur people to greater action. If it turns out to be incorrect there's no harm is there? It's not like we can overreact to climate change. Unless of course we can.
- Aerroon 5y ago
  >If it turns out to be incorrect there's no harm is there? It's not like we can overreact to climate change. We can. Human life is still resource constrained. While we live better lives than ever before, it's something that can always improve. The resources we spend on dealing with climate change could've been used to improve the lives of people instead. An investment in the economy today can have (positive) compounding effects in the future. We could live like people lived in the middle ages, but that would cause more human suffering than it would help. The same point goes for the future though - if we stop technological advancement, then how many people will suffer from issues of the modern day that would be solved in the future? Ultimately, it's a balancing act on what will help more people more in the long run.
- uh_uh 5y ago
  The harm in being incorrect is that more and more people will use the past incorrect statements as grounds to dismiss future potentially correct statements.
- GuB-42 5y ago
  Of course we can, ban fossil fuels overnight and nuke everyone who doesn't comply, nuclear winters are good against global warming. Reducing carbon emissions is tame as far as possible responses go, there are some extreme solutions involving geoengineering. It won't happen because there are more incentives for underreacting than overreacting but yes, definitely possible.
carlosf 5y ago
We can't predict shit like whether is gonna be sunny tomorrow, truth is the consequences of climate change are unknown, as the earth is a terribly complex system. Just like Covid, economics, politics... my only prediction is that most predictions will sound stupid after we start feeling the effects of climate change (for good or bad reasons, who knows). My personal philosophy is not to mess with complex systems if that can have fatal consequences, but I guess we are way past this point.
zidel 5y ago
> What are the actual consequences of the globe warming by 2 degrees instead of 1.5 degrees? IPCC SR1.5 [0] deals with this question. Figure SPM.2 [1] is probably a good place to start for a quick look, and the summary for policymakers has 4 pages (part B) that all seem directly related to your question. [0] https://www.ipcc.ch/sr15/ https://www.ipcc.ch/sr15/ [1] https://www.ipcc.ch/sr15/chapter/spm/b/spm2/ https://www.ipcc.ch/sr15/chapter/spm/b/spm2/

bioinformatics 5y ago

Not a mathematician, but >2 degrees instead of 1.5 degrees it's about 0.5 degrees.

pantalaimon 5y ago

My main worry is increasing droughts that will jeopardize our food supply.

eplanit 5y ago
Prepare now... pressure your state to build reservoirs.
- Y_Y 5y ago
  The problem with food reservoirs is that the stuff at the bottom tends to go bad before you can get to it.
  - eplanit 5y ago
    Reservoirs as in lakes for water.
missedthecue 5y ago
Climate change has been shown in many studies to increase food production, because carbon is an input to photosynthesis.

stevep98 5y ago

My understanding is that 2 degrees is not that harmful in itself, but it would lead to further uncontrollable runaway increases due to release of methane locked in frozen tundra.

cableshaft 5y ago
That, and also we would be reflecting less heat from the sun without the ice, as ice reflects back 90% of the sunlight that hits it, so no ice would lead to even more warming.

ajross 5y ago

The antarctic ice seems already to be melting, so Miami (also the port regions of most cities -- Shanghai has like 15M people living in likely flood zones!) is going under at this stage no matter what we do. Likewise the deep ocean circulation has already begun to collapse, so an anoxic ocean floor seems inevitable. The mass extinction event seems under way already. But the modelling is noisy, so no one can give you serious answers to "how will this affect people" that will meet your demand for precision. But the worst cases are all disastrous. Things like "we can't grow food in south asia to feed the 2-3 billion people there" are very much on the table.

hackeraccount 5y ago
How much would a sea wall around Miami or Shanghai cost?
- nradov 5y ago
  A sea wall around Miami wouldn't help due to the karst substrate; water would flow through the limestone channels under any wall. The main concern with sea level rise in South Florida isn't that the seawater will come in but that rainwater won't drain away. There will have to be a huge investment in pumping systems.
  - missedthecue 5y ago
    That investment is likely cheaper and more feasible than geo-engineering the globe's climate.
lotsofclaimsbud 5y ago
You got any citation for this opinion or any other one in your post history? You speak like you're an expert on this subject and others are voting like they trust you, but why? I don't see anything in your profile or history that indicates that you know what you're talking about, and you've provided no evidence here. Your comment sounds like fear mongering to me.
jjcon 5y ago

fallingfrog 5y ago

My ballpark guess: climate regions will shift north by a few hundred miles. In some places that will mean tundra turns to forest, in other places farmland will turn to desert. Sea levels will also rise by a few feet. But then there will be a couple billion people living in the wrong place; they will have to move across national borders in huge numbers. This is historically linked to political instability and sometimes war. The worst part will be what we do to each other as a result of climate change, rather than the change itself, imho.

kaybe 5y ago
This is an interesting paper in this regard: Bastin et al, Understanding climate change from a global analysis of city analogues: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0217592 https://journals.plos.org/plosone/article?id=10.1371/journal... "Even under an optimistic climate scenario (RCP 4.5), we found that 77% of future cities are very likely to experience a climate that is closer to that of another existing city than to its own current climate. In addition, 22% of cities will experience climate conditions that are not currently experienced by any existing major cities. " "We notably predict that Madrid’s climate in 2050 will resemble Marrakech’s climate today, Stockholm will resemble Budapest, London to Barcelona, Moscow to Sofia, Seattle to San Francisco, Tokyo to Changsha." The information might not be new, but the way it is presented is quite tangible, since many people have an understanding of today's conditions in different cities.
- senkora 5y ago
  Well, I guess I better buy property in Seattle, then.
- makomk 5y ago
  From what I recall, RCP 4.5 is closer to "status quo" than "optimistic" at least for a while yet.
  - kaybe 5y ago
    I agree. The authors probably had a bad day. Conferences can be depressing. The IPCC reports contain the very basic rock-solid consensus of what can be expected, but while playing around with data and models things can look much scarier.

jjcon 5y ago

> I see some people say it is going to make earth uninhabitable Not even the worst case scenarios from the IPCC show anything even remotely close to ‘uninhabitable earth’ - the people saying that are being even more disingenuous and pseudoscientific than climate deniers. Some fringe regions of the planet may become a lot harder to live in (note that climate change is not uniform, it will affect some places a lot more than others) and of course some coastal areas may experience more flooding but by and large day to day living in the first world will be similar to what it is today even with 2C of warming.

lotsofpulp 5y ago
> Some fringe regions of the planet may become a lot harder to live in (note that climate change is not uniform, it will affect some places a lot more than others) and of course some coastal areas may experience more flooding but by and large day to day living in the first world will be similar to what it is today even with 2C of warming. How can this be known at this point? I can certainly imagine changing weather patterns such as monsoon, drought, heat waves, cold snaps, etc not being limited to fringe regions.
- jjcon 5y ago
  Because we are already seeing it and can model for the future. See the first image in this article and note how some areas have experienced no warming while others a lot as compared to 1900. https://www.climate.gov/news-features/climate-qa/does-global-warming-mean-it’s-warming-everywhere https://www.climate.gov/news-features/climate-qa/does-global...
  - lotsofpulp 5y ago
    But I would not describe the areas experiencing change as “fringe”. Nor do I see a reason to expect the areas not experiencing change to continue not changing.
    - jjcon 5y ago
      ‘Experiencing change’ != ‘a lot harder to live in’ I didn’t say only fringe areas would change

sm0ss117 5y ago

Parts of India might get uninhabitable in the summer in some of the worse case scenarios. Given the population there and the fact they're a nuclear armed state that's a geopolitical powder keg.

hackeraccount 5y ago

In a dynamic system anyone who says they know the consequences with a high degree of certitude is blowing smoke. Oddly the most reasonable course of action is to always paint the worst possible future but it will presumably spur people to greater action. If it turns out to be incorrect there's no harm is there? It's not like we can overreact to climate change. Unless of course we can.

Aerroon 5y ago
>If it turns out to be incorrect there's no harm is there? It's not like we can overreact to climate change. We can. Human life is still resource constrained. While we live better lives than ever before, it's something that can always improve. The resources we spend on dealing with climate change could've been used to improve the lives of people instead. An investment in the economy today can have (positive) compounding effects in the future. We could live like people lived in the middle ages, but that would cause more human suffering than it would help. The same point goes for the future though - if we stop technological advancement, then how many people will suffer from issues of the modern day that would be solved in the future? Ultimately, it's a balancing act on what will help more people more in the long run.
uh_uh 5y ago
The harm in being incorrect is that more and more people will use the past incorrect statements as grounds to dismiss future potentially correct statements.
GuB-42 5y ago
Of course we can, ban fossil fuels overnight and nuke everyone who doesn't comply, nuclear winters are good against global warming. Reducing carbon emissions is tame as far as possible responses go, there are some extreme solutions involving geoengineering. It won't happen because there are more incentives for underreacting than overreacting but yes, definitely possible.

carlosf 5y ago

We can't predict shit like whether is gonna be sunny tomorrow, truth is the consequences of climate change are unknown, as the earth is a terribly complex system. Just like Covid, economics, politics... my only prediction is that most predictions will sound stupid after we start feeling the effects of climate change (for good or bad reasons, who knows). My personal philosophy is not to mess with complex systems if that can have fatal consequences, but I guess we are way past this point.

zidel 5y ago

> What are the actual consequences of the globe warming by 2 degrees instead of 1.5 degrees? IPCC SR1.5 [0] deals with this question. Figure SPM.2 [1] is probably a good place to start for a quick look, and the summary for policymakers has 4 pages (part B) that all seem directly related to your question. [0] https://www.ipcc.ch/sr15/ https://www.ipcc.ch/sr15/ [1] https://www.ipcc.ch/sr15/chapter/spm/b/spm2/ https://www.ipcc.ch/sr15/chapter/spm/b/spm2/