3 ms·

I thought we were sure about what will happen. Won't it, according to the models, lead to catastrophic global warming? We're spending enormous sums of taxpayers

by vixen99 11y ago

I thought we were sure about what will happen. Won't it, according to the models, lead to catastrophic global warming? We're spending enormous sums of taxpayers' money on that basis. It does also cause greening of the planet but that's of little interest to anyone.

danieltillett 11y ago
Yes in the long run the amount of greenhouse gases we have already released will result in very significant warming and the melting of all the ice caps. What we don't know for sure is how long this will take and if we will hit any positive feedback loops that will accelerate the process. If we do we will want to have other ways of keeping things from getting out of control.
- msandford 11y ago
  We also don't know if we'll run into any negative feedback loops that'll cause cooling, either. The Earth's climate seems to be pretty stable over the last few million years insofar as life has been able to exist in ways that are -- in terms of microbiology, our cells machinery -- very familiar. Given that we have record of that stability it seems likely that there are forces which push the climate towards that stability. Of course it's impossible to know for sure either way until it happens and we witness it and write it down.
  - DennisP 11y ago
    Actually the geological history is not reassuring. There have been multiple cases where the planet warmed a little due to orbital variations, and then positive feedbacks kicked in and took it several degrees further. Feedbacks evident in the record include ice melt, methane hydrate destabilization, permafrost melt releasing CO2 and methane, forest fires caused by drought, and CO2 release from dried-out topsoil and peat bogs. A good introduction to all this is in Hansen's book Storms of My Grandchildren. It's true that the past couple million years have been relatively stable. For at least the past 800,000 years CO2 never went higher than 280ppm. But the last time CO2 was as high as now, the planet was 3 to 6 degrees C warmer, and sea levels 25 to 40 meters higher: http://www.sciencemag.org/content/326/5958/1394.abstract http://www.sciencemag.org/content/326/5958/1394.abstract
- brc 11y ago
  The likelihood of positive feedback loops is very low, given that the Earth has had a relatively stable climate for a very long time. Any inherently unstable system would have degraded by now if susceptible to external shocks. The effects of greenhouse gases are mild compared with planetary collisions or large volcanic eruptions so it's unlikely any positive feedback loop will occur.
  - danieltillett 11y ago
    We really have no idea of what the risk of hitting a positive feedback loop is with global warning. Even if it is low do we want to risk it?
    - brc 11y ago
      The question of risk is always related to cost. It's common to use the 'insurance analogy' in these cases, or to invoke the 'precautionary principle'. The insurance analogy breaks down when you're paying 1/4 the cost of your house every 4 years to have it replaced in case of a possibility. We can't calculate the risk of an asteroid strike so we don't bother trying to avoid it or insure for it. Trying to solve an equation with one unknown variable is pointless, because there is only one correct value, and infinite incorrect values. Therefore the probability of wasting resources is extremely high. The precautionary principle is a recursive conundrum that eliminates itself and shouldn't be used in serious conversations. The facts point to a wait and see approach as the only rational response, given the availability of low cost approaches as in the original post here. This of course is not a popular response, but then most religions are based on the investment of time and money up front to deal with the unknown factor of what happens in the future. Unscrupulous people then use that fear to gather power and control over others. I'll always reject that thinking and use a wait and see approach.
      - danieltillett 11y ago
        The problem is not due to the costs involved in mitigation as these are quantifiable, but how to value the risk. Lets assume that the risk of total climate collapse is low, but the cost of such event is effectively infinite, then the no matter what the cost of preventing such a small risk it is worth doing. The insurance analogy is not the best one to use. A better analogy is if you had cancer and someone offered you a magic pill that cure you. How much would you pay for this drug? I know in my case it would be everything I own, as well as what I could earn in the future, just up to the point where I would cause excessive hardship to my family. When in comes to avoiding the risks of catastrophic climate change all the facts point towards doing lots of research to develop options given then cost of the research is relatively low and the risks with not having options very high.

by vixen99 11y ago

danieltillett 11y ago

Yes in the long run the amount of greenhouse gases we have already released will result in very significant warming and the melting of all the ice caps. What we don't know for sure is how long this will take and if we will hit any positive feedback loops that will accelerate the process. If we do we will want to have other ways of keeping things from getting out of control.

msandford 11y ago
We also don't know if we'll run into any negative feedback loops that'll cause cooling, either. The Earth's climate seems to be pretty stable over the last few million years insofar as life has been able to exist in ways that are -- in terms of microbiology, our cells machinery -- very familiar. Given that we have record of that stability it seems likely that there are forces which push the climate towards that stability. Of course it's impossible to know for sure either way until it happens and we witness it and write it down.
- DennisP 11y ago
  Actually the geological history is not reassuring. There have been multiple cases where the planet warmed a little due to orbital variations, and then positive feedbacks kicked in and took it several degrees further. Feedbacks evident in the record include ice melt, methane hydrate destabilization, permafrost melt releasing CO2 and methane, forest fires caused by drought, and CO2 release from dried-out topsoil and peat bogs. A good introduction to all this is in Hansen's book Storms of My Grandchildren. It's true that the past couple million years have been relatively stable. For at least the past 800,000 years CO2 never went higher than 280ppm. But the last time CO2 was as high as now, the planet was 3 to 6 degrees C warmer, and sea levels 25 to 40 meters higher: http://www.sciencemag.org/content/326/5958/1394.abstract http://www.sciencemag.org/content/326/5958/1394.abstract
brc 11y ago
The likelihood of positive feedback loops is very low, given that the Earth has had a relatively stable climate for a very long time. Any inherently unstable system would have degraded by now if susceptible to external shocks. The effects of greenhouse gases are mild compared with planetary collisions or large volcanic eruptions so it's unlikely any positive feedback loop will occur.
- danieltillett 11y ago
  We really have no idea of what the risk of hitting a positive feedback loop is with global warning. Even if it is low do we want to risk it?
  - brc 11y ago
    The question of risk is always related to cost. It's common to use the 'insurance analogy' in these cases, or to invoke the 'precautionary principle'. The insurance analogy breaks down when you're paying 1/4 the cost of your house every 4 years to have it replaced in case of a possibility. We can't calculate the risk of an asteroid strike so we don't bother trying to avoid it or insure for it. Trying to solve an equation with one unknown variable is pointless, because there is only one correct value, and infinite incorrect values. Therefore the probability of wasting resources is extremely high. The precautionary principle is a recursive conundrum that eliminates itself and shouldn't be used in serious conversations. The facts point to a wait and see approach as the only rational response, given the availability of low cost approaches as in the original post here. This of course is not a popular response, but then most religions are based on the investment of time and money up front to deal with the unknown factor of what happens in the future. Unscrupulous people then use that fear to gather power and control over others. I'll always reject that thinking and use a wait and see approach.
    - danieltillett 11y ago
      The problem is not due to the costs involved in mitigation as these are quantifiable, but how to value the risk. Lets assume that the risk of total climate collapse is low, but the cost of such event is effectively infinite, then the no matter what the cost of preventing such a small risk it is worth doing. The insurance analogy is not the best one to use. A better analogy is if you had cancer and someone offered you a magic pill that cure you. How much would you pay for this drug? I know in my case it would be everything I own, as well as what I could earn in the future, just up to the point where I would cause excessive hardship to my family. When in comes to avoiding the risks of catastrophic climate change all the facts point towards doing lots of research to develop options given then cost of the research is relatively low and the risks with not having options very high.