10 ms·

Even if the world is warm enough to melt the sheet completely, that would take centuries, if not millennia; Greenland's ice is thousands of meters thick. In a b

Even if the world is warm enough to melt the sheet completely, that would take centuries, if not millennia; Greenland's ice is thousands of meters thick. In a bad scenario, the IPCC forecasts 21st century sea level rise to be a bit under a meter (https://www.climatecentral.org/news/zeroing-in-on-ipccs-sea-level-rise-warming-hiatus-16532 https://www.climatecentral.org/news/zeroing-in-on-ipccs-sea-...). This will certainly cause problems, but is nothing like the complete and rapid destruction some pundits describe. Major action on carbon emissions is long overdue, and it's great that people are taking it more seriously now. But an overly-pessimistic scenario has the same problems as an overly-rosy scenario; if we're all doomed anyway, why do anything? Michael Mann, the climate scientist who famously brought global warming to public attention, now also spends time fighting doom scenarios which also discourage action: https://alumni.berkeley.edu/california-magazine/summer-2020/michael-mann-on-climate-denial-and-doom https://alumni.berkeley.edu/california-magazine/summer-2020/...

vlunkr 6y ago
Normally I like to say that HN has some of the best discussion on the internet, but the pessimism here is rivaling the political Facebook groups that everyone's racist uncle's share posts from.
jmole 6y ago
Even so - I'm reminded of the post the other day about the NYC street view photos from the 1940s [0] So little has changed in 80 years. Even given centuries of ice melt - how much cultural heritage do we lose with a 10m rise in sea levels that would devastate NYC? Then again, a century from now, maybe we're all living in personal generative VR paradises, ensconced in an anonymous room somewhere in a city unknown where power is cheap and proximity to a datacenter determines real estate pricing. [0] - https://1940s.nyc/map#13.69/40.7093/-73.99397 https://1940s.nyc/map#13.69/40.7093/-73.99397
- emmelaich 6y ago
  Possibly very little. The Dutch have many habitats below sea level. The main airport is 15m below.
  - fiblye 6y ago
    They're also a wealthy, densely packed, small country that had foresight and has been consistently building forever now. I think most places will just deny, deny, deny until they're ankle-deep then say there's nothing that can be done. Other places will acknowledge the problem, but not have the materials and people to do much. New York is one place with the wealth and people to build a sea barrier, but whether it'll be politically viable against the focus-on-the-economy-of-today opponents is another matter.
    - luckylion 6y ago
      > They're also a wealthy, densely packed, small country that had foresight and has been consistently building forever now. And they've done most of it with primitive technology compared to today's options. I agree though: it's a political decision, the engineering and building isn't the problem, and, I believe, neither is the budget. If your 16th century farming community could afford to build dikes, so can the 21st century techo-dystopian mega-cities.
  - rapnie 6y ago
    Fifteen meters is a bit too much, the lowest point is about 22 feet below (6.7m). Quoting Wikipedia: The Netherlands is geographically very low relative to sea level and is considered a flat country, with about 26% of its area and 21% of its population located below sea level, and only about 50% of its land exceeding one metre above sea level. https://en.wikipedia.org/wiki/Netherlands https://en.wikipedia.org/wiki/Netherlands I live below sea level myself. Most Dutch don't feel too worried, and think that with rising sea levels we'll just fix things on our shores and dikes. And good chance we will, by throwing huge amounts of money at infrastructure projects. And here you have the problem with climate change, and destruction of our world in general: the richer you are, the less affected you are. The poor fall from the map first. It is places like Bangladesh and inhabitants of tropical islands that'll fall victim before us rich folks do. For the absolute biggest polluters, the big barons, oligarchs and plutocrats, this problem does not exist. There will always be a tropical paradise island to own, bluefin tuna to eat, and elephants and lions to hunt.
solinent 6y ago
If you're interested in a healthy dose of climate change skepticism, there's also Richard Lindzen, but he's also derided by the climatologist community. I've found the most intelligent of the entire community is skeptical, but the rest of them are convinced of their mission for ethical means, and are willing to forecast doomsday scenarios based on essentially what boils down to linear regression or maybe some very simplified model that has no chance of being reality. The more complex models are still extremely rudimentary, with fluid sims in movies and games being more robust than GCM in terms of simulation size which has a massive effect on the prediction quality. And there are gaping holes--the ocean's fluid flow effects and clouds. (edit: apparently there are some simulations with these now, but they are very rudimentary, see below) Listen to him if you're interested though, his videos are all around YouTube. > Typical AGCM resolutions are between 1 and 5 degrees in latitude or longitude: HadCM3, for example, uses 3.75 in longitude and 2.5 degrees in latitude, giving a grid of 96 by 73 points (96 x 72 for some variables); and has 19 vertical levels. From Wikipedia. I don't think clouds fit into such a coarse grid. Climate is exceptionally chaotic and there are definitely processes that can't be approximated with such a low-parameter model. I dunno if the latest models are more refined, but six months ago they were still dealing with water vapor.
- onion2k 6y ago
  I've found the most intelligent of the entire community is skeptical... I'd be interested to know how you measured that.
  - solinent 6y ago
    Let's just say a combination of a few essentially computational factors--memory, conscientiousness, and scholarship and/or expertise through experience over a significant period of time in varied contexts. But really it's just my intuition, and I'm not the most intelligent person in the world so maybe I'm wrong. I don't really mean intelligence in the technical or usual sense, just in the sense that it applies to a climatologist that makes good predictions in this context. Anyways, I'm just here to deliver the message, I don't really pretend to know either way--but I do tend to agree with certain experts over others because their arguments are much more robust, given my math background it appeals to my reasonable side. edit: I thought about it some more. I think I can boil it down to one thing--high information entropy in their written work.
brainless 6y ago
This is a point that we need to think carefully. The melting projections are only as good as our understanding of our planet's systems. Just look at weather, are we really good at predicting it? We have come a long way but if we are not certain about next week's weather, how do we know what chain reactions are going to start, that can in-turn melt Greenland (Antarctic, etc.) ice way faster? We are literally scratching the tip of the iceberg (no pun intended). Our scientific models have changed recently and I am sure they will change again, soon. So why are we so sure that the melt will not accelerate to catastrophic levels? https://en.wikipedia.org/wiki/Antarctic_ice_sheet#Recent_observations https://en.wikipedia.org/wiki/Antarctic_ice_sheet#Recent_obs...
- dfee 6y ago
  > So why are we so sure that the melt will not accelerate to catastrophic levels? This is the sort of remark that undermines the cause.
  - anigbrowl 6y ago
    No it isn't. Your tone policing undermines the cause by making people afraid of even considering worst-case scenarios in case they get labeled as alarmists.
  - brainless 6y ago
    Undermines what and how? I am really interested in understanding this topic. I am an engineer by profession, I do not take things just because someone says so. And history is proof that humans barely have understanding of things. Every single recent study shows that things are accelerating. There is not a single scientific study showing a slow down of the melting process - not 1 study among hundreds. If anyone can share one, I would love to read.
    - sfkdjf9j3j 6y ago
      You want a study about something nobody has observed?
- 6y ago
cel1ne 6y ago
I like the way the 350.org science page put's it: 1. It’s warming. 2. It’s us. 3. We’re sure. 4. It’s bad. 5. We can fix it. (https://350.org/science/ https://350.org/science/)
- oh_sigh 6y ago
  Interesting that the claims get less and less certain as you go down the list.
- roenxi 6y ago
  The 'its bad' section could use some work; it isn't immediately obvious why it is bad. It says things like 10% decrease in grain yield. World population has increased by ~40% in my lifetime; so a 10% grain yield is not the biggest problem we're facing for food security. Ditto the 10 million migrant number. Australia has 7 million migrants living here right now; 10 million globally spread over many years is not particularly devastating. Climate change is supposed to be a threat significant enough for people to abandon their way of life, not those so-so numbers.
  - ed25519FUUU 6y ago
    Is there any evidence at all that global warming is causing any migration? I look at the problems in Syria and I’m definitely not saying “Yep global warming causes that.”
    - tito 6y ago
      The World Bank's Groundswell Report [0] from 2018 may be a useful resource for you: "Internal climate migrants are rapidly becoming the human face of climate change. According to the new World Bank report "Groundswell - Preparing for Internal Climate Migration", without urgent global and national climate action, Sub-Saharan Africa, South Asia and Latin America could see more than 140 million people move within their countries’ borders by 2050." [0] https://www.worldbank.org/en/news/infographic/2018/03/19/groundswell---preparing-for-internal-climate-migration https://www.worldbank.org/en/news/infographic/2018/03/19/gro...
lmilcin 6y ago
It is not true it must take centuries. We don't know how climate responds to changes but we know the response is highly nonlinear. Just yesterday I read how diminishing cloud cover can very rapidly tip Earth couple degrees up. Clouds reflect large portion of sunlight back to space. Less clouds equals less reflected energy equals more absorbed energy equals hotter environment equals less clouds. Ice takes decades to melt but clouds do not require to sink huge amount of energy and can vanish practically overnight as soon as atmosphere warms up enough. Once atmosphere warms up due to diminishing cloud cover the ice will melt very quickly, accelerated through external stimulus versus current slow feedback loop (less ice cover, etc).
- apsec112 6y ago
  The atmosphere can warm much faster than that, but even "very quick" melting would take forever, because it's hard-packed ice that's over a mile thick. At a melting rate of two meters per summer (which is a lot, that's the equivalent of melting ~800 inches of snow), it would take over a thousand years to get to the bottom.
unicornporn 6y ago
> it's great that people are taking it more seriously now. Quite frankly, I don't see it. Globally we emit over 36 billion tonnes of CO2 per year – this continues to increase[1]. [1] https://ourworldindata.org/co2-and-other-greenhouse-gas-emissions https://ourworldindata.org/co2-and-other-greenhouse-gas-emis...
_nalply 6y ago
The center of Greenland is below sea level and covered by about two miles of ice. Perhaps there could be a sudden collapse from below and two mile high icebergs strand somewhere along Florida's coast? Sadly I am rather pessimistic but I learnt something from my wife's cancer: we all die sooner or later, so in a special way it doesn't matter if humanity is dying. I do hope for my children that we find a way to salvage ourselves. Perhaps world-wide carbon capture and a giant freezers where neccessary?

vlunkr 6y ago

Normally I like to say that HN has some of the best discussion on the internet, but the pessimism here is rivaling the political Facebook groups that everyone's racist uncle's share posts from.

jmole 6y ago

Even so - I'm reminded of the post the other day about the NYC street view photos from the 1940s [0] So little has changed in 80 years. Even given centuries of ice melt - how much cultural heritage do we lose with a 10m rise in sea levels that would devastate NYC? Then again, a century from now, maybe we're all living in personal generative VR paradises, ensconced in an anonymous room somewhere in a city unknown where power is cheap and proximity to a datacenter determines real estate pricing. [0] - https://1940s.nyc/map#13.69/40.7093/-73.99397 https://1940s.nyc/map#13.69/40.7093/-73.99397

emmelaich 6y ago
Possibly very little. The Dutch have many habitats below sea level. The main airport is 15m below.
- fiblye 6y ago
  They're also a wealthy, densely packed, small country that had foresight and has been consistently building forever now. I think most places will just deny, deny, deny until they're ankle-deep then say there's nothing that can be done. Other places will acknowledge the problem, but not have the materials and people to do much. New York is one place with the wealth and people to build a sea barrier, but whether it'll be politically viable against the focus-on-the-economy-of-today opponents is another matter.
  - luckylion 6y ago
    > They're also a wealthy, densely packed, small country that had foresight and has been consistently building forever now. And they've done most of it with primitive technology compared to today's options. I agree though: it's a political decision, the engineering and building isn't the problem, and, I believe, neither is the budget. If your 16th century farming community could afford to build dikes, so can the 21st century techo-dystopian mega-cities.
- rapnie 6y ago
  Fifteen meters is a bit too much, the lowest point is about 22 feet below (6.7m). Quoting Wikipedia: The Netherlands is geographically very low relative to sea level and is considered a flat country, with about 26% of its area and 21% of its population located below sea level, and only about 50% of its land exceeding one metre above sea level. https://en.wikipedia.org/wiki/Netherlands https://en.wikipedia.org/wiki/Netherlands I live below sea level myself. Most Dutch don't feel too worried, and think that with rising sea levels we'll just fix things on our shores and dikes. And good chance we will, by throwing huge amounts of money at infrastructure projects. And here you have the problem with climate change, and destruction of our world in general: the richer you are, the less affected you are. The poor fall from the map first. It is places like Bangladesh and inhabitants of tropical islands that'll fall victim before us rich folks do. For the absolute biggest polluters, the big barons, oligarchs and plutocrats, this problem does not exist. There will always be a tropical paradise island to own, bluefin tuna to eat, and elephants and lions to hunt.

solinent 6y ago

If you're interested in a healthy dose of climate change skepticism, there's also Richard Lindzen, but he's also derided by the climatologist community. I've found the most intelligent of the entire community is skeptical, but the rest of them are convinced of their mission for ethical means, and are willing to forecast doomsday scenarios based on essentially what boils down to linear regression or maybe some very simplified model that has no chance of being reality. The more complex models are still extremely rudimentary, with fluid sims in movies and games being more robust than GCM in terms of simulation size which has a massive effect on the prediction quality. And there are gaping holes--the ocean's fluid flow effects and clouds. (edit: apparently there are some simulations with these now, but they are very rudimentary, see below) Listen to him if you're interested though, his videos are all around YouTube. > Typical AGCM resolutions are between 1 and 5 degrees in latitude or longitude: HadCM3, for example, uses 3.75 in longitude and 2.5 degrees in latitude, giving a grid of 96 by 73 points (96 x 72 for some variables); and has 19 vertical levels. From Wikipedia. I don't think clouds fit into such a coarse grid. Climate is exceptionally chaotic and there are definitely processes that can't be approximated with such a low-parameter model. I dunno if the latest models are more refined, but six months ago they were still dealing with water vapor.

onion2k 6y ago
I've found the most intelligent of the entire community is skeptical... I'd be interested to know how you measured that.
- solinent 6y ago
  Let's just say a combination of a few essentially computational factors--memory, conscientiousness, and scholarship and/or expertise through experience over a significant period of time in varied contexts. But really it's just my intuition, and I'm not the most intelligent person in the world so maybe I'm wrong. I don't really mean intelligence in the technical or usual sense, just in the sense that it applies to a climatologist that makes good predictions in this context. Anyways, I'm just here to deliver the message, I don't really pretend to know either way--but I do tend to agree with certain experts over others because their arguments are much more robust, given my math background it appeals to my reasonable side. edit: I thought about it some more. I think I can boil it down to one thing--high information entropy in their written work.

brainless 6y ago

This is a point that we need to think carefully. The melting projections are only as good as our understanding of our planet's systems. Just look at weather, are we really good at predicting it? We have come a long way but if we are not certain about next week's weather, how do we know what chain reactions are going to start, that can in-turn melt Greenland (Antarctic, etc.) ice way faster? We are literally scratching the tip of the iceberg (no pun intended). Our scientific models have changed recently and I am sure they will change again, soon. So why are we so sure that the melt will not accelerate to catastrophic levels? https://en.wikipedia.org/wiki/Antarctic_ice_sheet#Recent_observations https://en.wikipedia.org/wiki/Antarctic_ice_sheet#Recent_obs...

dfee 6y ago
> So why are we so sure that the melt will not accelerate to catastrophic levels? This is the sort of remark that undermines the cause.
- anigbrowl 6y ago
  No it isn't. Your tone policing undermines the cause by making people afraid of even considering worst-case scenarios in case they get labeled as alarmists.
- brainless 6y ago
  Undermines what and how? I am really interested in understanding this topic. I am an engineer by profession, I do not take things just because someone says so. And history is proof that humans barely have understanding of things. Every single recent study shows that things are accelerating. There is not a single scientific study showing a slow down of the melting process - not 1 study among hundreds. If anyone can share one, I would love to read.
  - sfkdjf9j3j 6y ago
    You want a study about something nobody has observed?
6y ago

cel1ne 6y ago

I like the way the 350.org science page put's it: 1. It’s warming. 2. It’s us. 3. We’re sure. 4. It’s bad. 5. We can fix it. (https://350.org/science/ https://350.org/science/)

oh_sigh 6y ago
Interesting that the claims get less and less certain as you go down the list.
roenxi 6y ago
The 'its bad' section could use some work; it isn't immediately obvious why it is bad. It says things like 10% decrease in grain yield. World population has increased by ~40% in my lifetime; so a 10% grain yield is not the biggest problem we're facing for food security. Ditto the 10 million migrant number. Australia has 7 million migrants living here right now; 10 million globally spread over many years is not particularly devastating. Climate change is supposed to be a threat significant enough for people to abandon their way of life, not those so-so numbers.
- ed25519FUUU 6y ago
  Is there any evidence at all that global warming is causing any migration? I look at the problems in Syria and I’m definitely not saying “Yep global warming causes that.”
  - tito 6y ago
    The World Bank's Groundswell Report [0] from 2018 may be a useful resource for you: "Internal climate migrants are rapidly becoming the human face of climate change. According to the new World Bank report "Groundswell - Preparing for Internal Climate Migration", without urgent global and national climate action, Sub-Saharan Africa, South Asia and Latin America could see more than 140 million people move within their countries’ borders by 2050." [0] https://www.worldbank.org/en/news/infographic/2018/03/19/groundswell---preparing-for-internal-climate-migration https://www.worldbank.org/en/news/infographic/2018/03/19/gro...

lmilcin 6y ago

It is not true it must take centuries. We don't know how climate responds to changes but we know the response is highly nonlinear. Just yesterday I read how diminishing cloud cover can very rapidly tip Earth couple degrees up. Clouds reflect large portion of sunlight back to space. Less clouds equals less reflected energy equals more absorbed energy equals hotter environment equals less clouds. Ice takes decades to melt but clouds do not require to sink huge amount of energy and can vanish practically overnight as soon as atmosphere warms up enough. Once atmosphere warms up due to diminishing cloud cover the ice will melt very quickly, accelerated through external stimulus versus current slow feedback loop (less ice cover, etc).

apsec112 6y ago
The atmosphere can warm much faster than that, but even "very quick" melting would take forever, because it's hard-packed ice that's over a mile thick. At a melting rate of two meters per summer (which is a lot, that's the equivalent of melting ~800 inches of snow), it would take over a thousand years to get to the bottom.

unicornporn 6y ago

> it's great that people are taking it more seriously now. Quite frankly, I don't see it. Globally we emit over 36 billion tonnes of CO2 per year – this continues to increase[1]. [1] https://ourworldindata.org/co2-and-other-greenhouse-gas-emissions https://ourworldindata.org/co2-and-other-greenhouse-gas-emis...

_nalply 6y ago

The center of Greenland is below sea level and covered by about two miles of ice. Perhaps there could be a sudden collapse from below and two mile high icebergs strand somewhere along Florida's coast? Sadly I am rather pessimistic but I learnt something from my wife's cancer: we all die sooner or later, so in a special way it doesn't matter if humanity is dying. I do hope for my children that we find a way to salvage ourselves. Perhaps world-wide carbon capture and a giant freezers where neccessary?