10 ms·

Pliocene and Eocene provide best analogs for near-future climates

54 points by howard941 8y ago

sudden 8y ago
Is human made climate change real?
- spenczar5 8y ago
  Yes.
  - nothrabannosir 8y ago
    This answer is vastly underrated. Sometimes, a simple question begets a simple answer. Especially when asked in earnest. We can assume it’s a troll, but someone out there asking this, is not. I know there are people with an agenda who aren’t interested in an answer, and will say whatever to poison the water. But I honestly believe that, at least in their sphere of influence , they captured well meaning people who just happen to be getting a very one sided perspective on it all. Sure, they too might not always seem honestly asking , but they are human and we are tribal creatures. We can’t expect everyone to constantly question their friends. But deep down inside , perhaps some people aren’t as sure as they pretend to be. Perhaps they are honestly asking, somewhere, deep down. And if they are , they’re not asking for facts. They’re asking for trust. Is it, really, real? Showering people in facts doesn’t always help. Sometimes, we just need to look across the divide and say: Yes. Yes, it really, really, is real. Please take our word for it. This is serious. We beg of you. And we need your help. At least, that’s my theory.
- my_first_acct 8y ago
  According to the abstract (I haven't tried to access the full article), the researchers take standard academic climate models (for instance, HadCM3 [1]), plug in some assumptions about future CO2 emissions, and compare the results to what is known about Eocene and Pliocene climates. If these academic models reflect reality (and several generations of climate scientists have tried to ensure that they do), then human-made climate change is "real". But if for some reason you believe that all these climate models are incorrect, then you will probably find this article to be of little interest. [1] https://en.wikipedia.org/wiki/HadCM3 https://en.wikipedia.org/wiki/HadCM3
- feistypharit 8y ago
  Even if it's not, we know the output of internal combustion engines is bad for us and can kill us in confined spaces. Our atmosphere is a confined space.
  - p1mrx 8y ago
    That's a red herring. Most modern engines are designed to burn cleanly enough that their direct pollution won't overwhelm the atmosphere. When you burn fossil fuels, CO2 production is unavoidable, and reversing the process necessarily requires more energy than the fuel released. The atmosphere and fuels form a giant battery that takes millions of years to recharge, where the discharged state produces a hotter climate.
- vowelless 8y ago
  Usually I dislike engaging with trolls but this topic is important. sudden, are you familiar aware that we have more co2 today than before? Would you agree that burning of organic matter produces co2? That burning fossil fuels produce co2? Next part: are you familiar with the fact some some gasses exhibit “greenhouse effect”? (like opening the door of your car on a hot day, the inside is much hotter than outside). Do you know that co2 is one such gas? Combining those two things, can you imagine how co2 increase can trap more heat in the earth? Given this mental model and hypothesis, first make sure that it is consistent. If the above is true then we should be able to measure various aspects to test this theory. Run an experiment to see if co2 is indeed green house gas. Run an experiment to measure co2 output from various things like fuel burning, cattle, etc. Measure historical co2 levels. Measure historical sea levels. All of these things are measurable / empirical. So at least we can understand the past very well. The question about the future is hard but we can definitely prove or disprove weather human made climate change is reall. Just need to answer those questions. Either it is or it isn’t. I can assure you that it is real but I will let you investigate those questions yourself.
  - Waterluvian 8y ago
    Is there a term for this chaining together of a logical argument? It's elegant.
    - StavrosK 8y ago
      "logic"?
      - Waterluvian 8y ago
        I was looking for something more specific describing the actual exercise. Kind of the Socratic method but with no argumentative segment.
        StavrosK 8y ago
        I don't think there's something more specific, I think it's just the rudimentary laying out of the steps of the argument.
- thinkingkong 8y ago
  People tend to think equality in airtime is equality in argument. There are so many published papers about this subject that there are papers about consensus on consensus within the scientific community. The tl;dr is 90-100% of scientists agree that humans are causing climate change. http://iopscience.iop.org/article/10.1088/1748-9326/11/4/048002 http://iopscience.iop.org/article/10.1088/1748-9326/11/4/048...
maxander 8y ago
> Both the emergence of geologically novel climates and the rapid reversion to Eocene-like climates may be outside the range of evolutionary adaptive capacity. A lovely little sentence, elegantly understated and used as a seemingly off-handed conclusion to the abstract, which essentially means "the world may be about to end." Also, NASA is hosting the full article: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20180008801.pdf https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/201800...
- grondilu 8y ago
  What is the range of evolutionary adaptive capacity, though? Life has survived everything that has been thrown at it in several billion years. We just don't know what it would take to wipe it all. So I don't think the authors were talking about the complete end of life. They were just saying that we're going towards a phase of mass extinction, and that is not much controversial.
  - deleted 8y ago
    [deleted]
  - dpau 8y ago
    > we are effectively rewinding the climate clock by approximately 50 My, reversing a multimillion year cooling trend in less than two centuries. It’s the unprecedented suddenness of this climate change that makes it doubtful organisms will be able to adapt. Maybe we shouldn’t be concerned with whether or not some form of life will still exist, but whether or not we will.
    - politician 8y ago
      It's time to start building domes.
      - Reelin 8y ago
        Not domes so much as greenhouses. The climate change doesn't kill you, it kills the crops you depend on to live and then you starve.
vivekd 8y ago
Pliocene like climates by 2040 is easy for me to swallow, after all the climates then seem similar to modern climates just warmer. Eocene like climates by 2050 is a bit harder to swallow. It's hard to imagine there being a tropical environment in the Arctic that can support alligators and Tortoises in about 30 years time. Going from Pliocene to Eocene climates in as little as 10 years time makes me think the model either assumed a huge increase in greenhouse gas production with India and China becoming superpowers or assumed a runaway greenhouse effect.
- seiferteric 8y ago
  It could just be due to exponential changes being hard to reason about, tipping points and all that.
- maxander 8y ago
  Skimming the paper, it looks like they predict pliocene/eocene climates primarily for equatorial zones, with polar and high-latitude regions less effected. Eocene climates were also more even, with less of a difference between polar and equatorial temperatures. So alligators in the arctic is not strictly being predicted (at least not on that timescale, and that's not to say the predictions aren't scary in plenty of other ways.)
- Abishek_Muthian 8y ago
  > The Mid-Pliocene becomes the best climate analog slightly sooner, by 2030 CE, but the prevalence of Eocene-like climates accelerates after 2050CE, and future climates most commonly resemble the Eocene by 2140 CE Changes towards Eocene accelerates by 2050 according to the models & doesn't reflect Eocene until 2140 CE. Still the rate of change is incomprehensible IMO.
i_feel_great 8y ago
Which of our major food-crops can handle Pliocene and Eocene climates?
- throwaway5752 8y ago
  None. Obviously this is suggesting mass human die-off or total extinction.
  - i_feel_great 8y ago
    Famine -> law and order breakdown -> mass migrations -> wars and military conflicts -> population reductions. Hmmm. I have read this in human history before.
- Reelin 8y ago
  Complicated question - it's called climate change for a reason. Unfortunately I found it difficult to turn up easy to read climate maps for different historical periods, but I did manage to find a couple. First our baseline - check out this very detailed present day biome map.[1] For an idea of what things probably looked like during the Pliocene, check out this biome map.[2] Note that a portion of the central US (our bread basket, so to speak) was desert. But then, also notice that a large swath of Texas was actually grassland and that temperate forest extended down to approximately LA. As for the Eocene, things actually look pretty good in the US crop wise. From figure 6 of this paper [3], it looks like the west coast was warm temperate forest while almost the entire rest of the US was tropical forest. That being said, don't get the wrong idea. Just because you can still grow crops doesn't mean you can grow the same crops, or in the same places; things will probably not be going so well. In a best case scenario climate change still presumably causes massive disruptions to our societies as well as large scale economic damage simply by rapidly changing things. [1] https://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/use/worldsoils/?cid=nrcs142p2_054002 https://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/use/w... [2] https://en.wikipedia.org/wiki/Pliocene_climate#/media/File:Pliocene_megabiome.png https://en.wikipedia.org/wiki/Pliocene_climate#/media/File:P... [3] https://www.geosci-model-dev.net/7/2077/2014/gmd-7-2077-2014.pdf https://www.geosci-model-dev.net/7/2077/2014/gmd-7-2077-2014...
baking 8y ago
For anyone interested in finding out more about the last 50-60 million years of climate history I would strongly recommend this talk: https://www.youtube.com/watch?v=Yze1YAz_LYM https://www.youtube.com/watch?v=Yze1YAz_LYM
- deleted 8y ago
  [deleted]
carboy 8y ago
I think we passed the tipping point for the climate 25 years ago, we just didn’t know it, or even today full grasp it. I was saying 10 years ago they by 2024-2028 we would see runaway climate changes. I have friends and relatives that are climate related research scientists. 10, 5, and 3 years ago they thought I was crazy, last year they have all expressed concerns that I might have underestimated the speed of change. They are very scared. I hope I’m wrong, but I don’t think I am.
- KnightOfWords 8y ago
  Depends what you mean by 'runaway climate change'. It takes some time for climate to stabilize, even if we stopped all carbon emission now it would take a few decades for the planet to reach equilibrium. We've certainly reached the point where significant impacts are going to be felt but not necessarily to the point where, say, the Earth loses all polar ice and remains hot for tens of thousands of years. > I was saying 10 years ago they by 2024-2028 we would see runaway climate changes. > 10, 5, and 3 years ago they thought I was crazy, last year they have all expressed concerns that I might have underestimated the speed of change. It's important to recognise that neither you nor I have the expertise to truly assess this. The climate models are the best we have but there are various uncertainties. I'm also concerned that they may turn out to be too conservative but it will take many years to find out. The most optimistic scenario is that the models break in our favour, serious action is taken, technology bails us out somewhat and investment in low-carbon energy and sustainable farming provides employment. The worst case scenario is that crop yields and fisheries collapse well before the end of the century.

54 points by howard941 8y ago

sudden 8y ago

Is human made climate change real?

spenczar5 8y ago
Yes.
- nothrabannosir 8y ago
  This answer is vastly underrated. Sometimes, a simple question begets a simple answer. Especially when asked in earnest. We can assume it’s a troll, but someone out there asking this, is not. I know there are people with an agenda who aren’t interested in an answer, and will say whatever to poison the water. But I honestly believe that, at least in their sphere of influence , they captured well meaning people who just happen to be getting a very one sided perspective on it all. Sure, they too might not always seem honestly asking , but they are human and we are tribal creatures. We can’t expect everyone to constantly question their friends. But deep down inside , perhaps some people aren’t as sure as they pretend to be. Perhaps they are honestly asking, somewhere, deep down. And if they are , they’re not asking for facts. They’re asking for trust. Is it, really, real? Showering people in facts doesn’t always help. Sometimes, we just need to look across the divide and say: Yes. Yes, it really, really, is real. Please take our word for it. This is serious. We beg of you. And we need your help. At least, that’s my theory.
my_first_acct 8y ago
According to the abstract (I haven't tried to access the full article), the researchers take standard academic climate models (for instance, HadCM3 [1]), plug in some assumptions about future CO2 emissions, and compare the results to what is known about Eocene and Pliocene climates. If these academic models reflect reality (and several generations of climate scientists have tried to ensure that they do), then human-made climate change is "real". But if for some reason you believe that all these climate models are incorrect, then you will probably find this article to be of little interest. [1] https://en.wikipedia.org/wiki/HadCM3 https://en.wikipedia.org/wiki/HadCM3
feistypharit 8y ago
Even if it's not, we know the output of internal combustion engines is bad for us and can kill us in confined spaces. Our atmosphere is a confined space.
- p1mrx 8y ago
  That's a red herring. Most modern engines are designed to burn cleanly enough that their direct pollution won't overwhelm the atmosphere. When you burn fossil fuels, CO2 production is unavoidable, and reversing the process necessarily requires more energy than the fuel released. The atmosphere and fuels form a giant battery that takes millions of years to recharge, where the discharged state produces a hotter climate.
vowelless 8y ago
Usually I dislike engaging with trolls but this topic is important. sudden, are you familiar aware that we have more co2 today than before? Would you agree that burning of organic matter produces co2? That burning fossil fuels produce co2? Next part: are you familiar with the fact some some gasses exhibit “greenhouse effect”? (like opening the door of your car on a hot day, the inside is much hotter than outside). Do you know that co2 is one such gas? Combining those two things, can you imagine how co2 increase can trap more heat in the earth? Given this mental model and hypothesis, first make sure that it is consistent. If the above is true then we should be able to measure various aspects to test this theory. Run an experiment to see if co2 is indeed green house gas. Run an experiment to measure co2 output from various things like fuel burning, cattle, etc. Measure historical co2 levels. Measure historical sea levels. All of these things are measurable / empirical. So at least we can understand the past very well. The question about the future is hard but we can definitely prove or disprove weather human made climate change is reall. Just need to answer those questions. Either it is or it isn’t. I can assure you that it is real but I will let you investigate those questions yourself.
- Waterluvian 8y ago
  Is there a term for this chaining together of a logical argument? It's elegant.
  - StavrosK 8y ago
    "logic"?
    - Waterluvian 8y ago
      I was looking for something more specific describing the actual exercise. Kind of the Socratic method but with no argumentative segment.
      - StavrosK 8y ago
        I don't think there's something more specific, I think it's just the rudimentary laying out of the steps of the argument.
thinkingkong 8y ago
People tend to think equality in airtime is equality in argument. There are so many published papers about this subject that there are papers about consensus on consensus within the scientific community. The tl;dr is 90-100% of scientists agree that humans are causing climate change. http://iopscience.iop.org/article/10.1088/1748-9326/11/4/048002 http://iopscience.iop.org/article/10.1088/1748-9326/11/4/048...

maxander 8y ago

> Both the emergence of geologically novel climates and the rapid reversion to Eocene-like climates may be outside the range of evolutionary adaptive capacity. A lovely little sentence, elegantly understated and used as a seemingly off-handed conclusion to the abstract, which essentially means "the world may be about to end." Also, NASA is hosting the full article: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20180008801.pdf https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/201800...

grondilu 8y ago
What is the range of evolutionary adaptive capacity, though? Life has survived everything that has been thrown at it in several billion years. We just don't know what it would take to wipe it all. So I don't think the authors were talking about the complete end of life. They were just saying that we're going towards a phase of mass extinction, and that is not much controversial.
- deleted 8y ago
  [deleted]
- dpau 8y ago
  > we are effectively rewinding the climate clock by approximately 50 My, reversing a multimillion year cooling trend in less than two centuries. It’s the unprecedented suddenness of this climate change that makes it doubtful organisms will be able to adapt. Maybe we shouldn’t be concerned with whether or not some form of life will still exist, but whether or not we will.
  - politician 8y ago
    It's time to start building domes.
    - Reelin 8y ago
      Not domes so much as greenhouses. The climate change doesn't kill you, it kills the crops you depend on to live and then you starve.

vivekd 8y ago

Pliocene like climates by 2040 is easy for me to swallow, after all the climates then seem similar to modern climates just warmer. Eocene like climates by 2050 is a bit harder to swallow. It's hard to imagine there being a tropical environment in the Arctic that can support alligators and Tortoises in about 30 years time. Going from Pliocene to Eocene climates in as little as 10 years time makes me think the model either assumed a huge increase in greenhouse gas production with India and China becoming superpowers or assumed a runaway greenhouse effect.

seiferteric 8y ago
It could just be due to exponential changes being hard to reason about, tipping points and all that.
maxander 8y ago
Skimming the paper, it looks like they predict pliocene/eocene climates primarily for equatorial zones, with polar and high-latitude regions less effected. Eocene climates were also more even, with less of a difference between polar and equatorial temperatures. So alligators in the arctic is not strictly being predicted (at least not on that timescale, and that's not to say the predictions aren't scary in plenty of other ways.)
Abishek_Muthian 8y ago
> The Mid-Pliocene becomes the best climate analog slightly sooner, by 2030 CE, but the prevalence of Eocene-like climates accelerates after 2050CE, and future climates most commonly resemble the Eocene by 2140 CE Changes towards Eocene accelerates by 2050 according to the models & doesn't reflect Eocene until 2140 CE. Still the rate of change is incomprehensible IMO.

i_feel_great 8y ago

Which of our major food-crops can handle Pliocene and Eocene climates?

throwaway5752 8y ago
None. Obviously this is suggesting mass human die-off or total extinction.
- i_feel_great 8y ago
  Famine -> law and order breakdown -> mass migrations -> wars and military conflicts -> population reductions. Hmmm. I have read this in human history before.
Reelin 8y ago
Complicated question - it's called climate change for a reason. Unfortunately I found it difficult to turn up easy to read climate maps for different historical periods, but I did manage to find a couple. First our baseline - check out this very detailed present day biome map.[1] For an idea of what things probably looked like during the Pliocene, check out this biome map.[2] Note that a portion of the central US (our bread basket, so to speak) was desert. But then, also notice that a large swath of Texas was actually grassland and that temperate forest extended down to approximately LA. As for the Eocene, things actually look pretty good in the US crop wise. From figure 6 of this paper [3], it looks like the west coast was warm temperate forest while almost the entire rest of the US was tropical forest. That being said, don't get the wrong idea. Just because you can still grow crops doesn't mean you can grow the same crops, or in the same places; things will probably not be going so well. In a best case scenario climate change still presumably causes massive disruptions to our societies as well as large scale economic damage simply by rapidly changing things. [1] https://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/use/worldsoils/?cid=nrcs142p2_054002 https://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/use/w... [2] https://en.wikipedia.org/wiki/Pliocene_climate#/media/File:Pliocene_megabiome.png https://en.wikipedia.org/wiki/Pliocene_climate#/media/File:P... [3] https://www.geosci-model-dev.net/7/2077/2014/gmd-7-2077-2014.pdf https://www.geosci-model-dev.net/7/2077/2014/gmd-7-2077-2014...

baking 8y ago

For anyone interested in finding out more about the last 50-60 million years of climate history I would strongly recommend this talk: https://www.youtube.com/watch?v=Yze1YAz_LYM https://www.youtube.com/watch?v=Yze1YAz_LYM

deleted 8y ago
[deleted]

carboy 8y ago

I think we passed the tipping point for the climate 25 years ago, we just didn’t know it, or even today full grasp it. I was saying 10 years ago they by 2024-2028 we would see runaway climate changes. I have friends and relatives that are climate related research scientists. 10, 5, and 3 years ago they thought I was crazy, last year they have all expressed concerns that I might have underestimated the speed of change. They are very scared. I hope I’m wrong, but I don’t think I am.

KnightOfWords 8y ago
Depends what you mean by 'runaway climate change'. It takes some time for climate to stabilize, even if we stopped all carbon emission now it would take a few decades for the planet to reach equilibrium. We've certainly reached the point where significant impacts are going to be felt but not necessarily to the point where, say, the Earth loses all polar ice and remains hot for tens of thousands of years. > I was saying 10 years ago they by 2024-2028 we would see runaway climate changes. > 10, 5, and 3 years ago they thought I was crazy, last year they have all expressed concerns that I might have underestimated the speed of change. It's important to recognise that neither you nor I have the expertise to truly assess this. The climate models are the best we have but there are various uncertainties. I'm also concerned that they may turn out to be too conservative but it will take many years to find out. The most optimistic scenario is that the models break in our favour, serious action is taken, technology bails us out somewhat and investment in low-carbon energy and sustainable farming provides employment. The worst case scenario is that crop yields and fisheries collapse well before the end of the century.