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I don't think you have understood my point at all. I am not claiming that this is a demonstration of human-caused global warming. I'm explaining why scientist

I don't think you have understood my point at all. I am not claiming that this is a demonstration of human-caused global warming. I'm explaining why scientists now consider human-caused global warming to be the null hypothesis. Which is to say that unless some currently unknown factor comes into play, they expect the planet to continue to warm as we release more and more CO2 into the atmosphere. Why is that important? Well, it basically means that if you want to claim that something other than substantial global warming is going to occur, then the onus is on you to demonstrate that there is some other process in play that the current model has failed to take into account. So sure, there may be other other major factors that affect climate. I have no problem with that possibility. But those factors are a bit like those old maps with "Here Be Dragons" marked when the map-maker didn't know what was really there. As we explored more and made better maps, those blank areas disappeared until there were none left (and we never did find any dragons!) Maybe this time we will find dragons, and there really is some other factor that balances out our increased CO2 emissions. But for the time being, no-one has discovered any such factor. Is it really reasonable to base public policy on the bet that this time, we really will find dragons?

krschultz 15y ago
But you have completely hand waved the argument and its consequences. You have made an argument that CO2 means that it is likely to be warmer. So? What's the problem? I like the summer. Obviously the problem is not that it will be slightly warmer. The problem is that ice caps will melt, the weather will change, sea levels will rise, farm land may be harder to come by, species may die, etc etc etc. All of that could end up being very bad. If it is that bad then it is worth preventing. But how do you go from 'CO2 traps heat' to 'We're screwed!'. That's the part people disagree with. All of these effects are way harder to show in an experiment than simply that CO2 absorbs heat. How do you do a full-scale experiment with cloud formation or the increased hurricanes we're supposedly going to see? You simply can't do an experiment. This is not to say the models are wrong, just that saying CO2 can be shown to trap heat is not the answer people are looking for. That is well understood. The 2nd and 3rd order effects are what really get called into question.
- demallien 15y ago
  Ok, firstly: "But how do you go from 'CO2 traps heat' to 'We're screwed!'" Honestly, I don't know, that's why I didn't do that! That said, with our current understanding, not just that CO2 traps heat, but how much heat a certain concentration of CO2 traps, we are able to anticipate a certain rise in temperature. Yes, there is maybe some unknown process that will interrupt this rise in temperature, but for the time being we know of no mechanism that will do so. Do you want to bet the planet on the idea that there is an unknown process, for which we have no evidence, that is going to stop the planet from warming up dramatically, as our models predict it will in the absence of such an unknown factor? If I were to say to you "Hey, our current projections show that if we continue fishing Blue Fin Tuna at the current rate, they will go extinct in 15 years", do you consider it a reasonable response to say "Tuna population change is a complicated phenomenum. Maybe there's something that we've missed which means that the tuna population will bounce back, regardless of our fishing levels. Therefore, let's keep on fishing as we always have."? Because that's pretty much what you seem to be arguing for with respect to climate change.
  - krschultz 15y ago
    That's not what I'm arguing at all. These models show that temperatures are going to rise. Your tuna model shows that tuna populations will fall after overfishing. At the end of my climate model, I have a world with a higher average temperature. At the end of your tuna model, we have a world with no tuna. I fully agree with both of those. But the consequences are a lot less clear. Obviously a world with no tuna is one where I don't like the menu at a sushi restaurent as much. I want to avoid that, I see a negative consequence there directly related to the model, no other models required. What is the negative consequence of higher average temperatures? There are models showing things like more storms, higher sea levels, drought, etc etc etc. Those are definitely things we want to avoid. But those secondary models are a hell of a lot less concrete than the temperature models. We might have more drought in some places but more crop yield in others. If we have more storms obviously there is more cloud formation - won't that be a negative feedback on temperature? Those things are a lot harder to show and thats what I don't think has been sufficiently proven. We aren't really concerned with the change in temperature. We are concerned with the consequences of the change in temperature on the world's weather. That is a significant difference.

krschultz 15y ago

But you have completely hand waved the argument and its consequences. You have made an argument that CO2 means that it is likely to be warmer. So? What's the problem? I like the summer. Obviously the problem is not that it will be slightly warmer. The problem is that ice caps will melt, the weather will change, sea levels will rise, farm land may be harder to come by, species may die, etc etc etc. All of that could end up being very bad. If it is that bad then it is worth preventing. But how do you go from 'CO2 traps heat' to 'We're screwed!'. That's the part people disagree with. All of these effects are way harder to show in an experiment than simply that CO2 absorbs heat. How do you do a full-scale experiment with cloud formation or the increased hurricanes we're supposedly going to see? You simply can't do an experiment. This is not to say the models are wrong, just that saying CO2 can be shown to trap heat is not the answer people are looking for. That is well understood. The 2nd and 3rd order effects are what really get called into question.

demallien 15y ago
Ok, firstly: "But how do you go from 'CO2 traps heat' to 'We're screwed!'" Honestly, I don't know, that's why I didn't do that! That said, with our current understanding, not just that CO2 traps heat, but how much heat a certain concentration of CO2 traps, we are able to anticipate a certain rise in temperature. Yes, there is maybe some unknown process that will interrupt this rise in temperature, but for the time being we know of no mechanism that will do so. Do you want to bet the planet on the idea that there is an unknown process, for which we have no evidence, that is going to stop the planet from warming up dramatically, as our models predict it will in the absence of such an unknown factor? If I were to say to you "Hey, our current projections show that if we continue fishing Blue Fin Tuna at the current rate, they will go extinct in 15 years", do you consider it a reasonable response to say "Tuna population change is a complicated phenomenum. Maybe there's something that we've missed which means that the tuna population will bounce back, regardless of our fishing levels. Therefore, let's keep on fishing as we always have."? Because that's pretty much what you seem to be arguing for with respect to climate change.
- krschultz 15y ago
  That's not what I'm arguing at all. These models show that temperatures are going to rise. Your tuna model shows that tuna populations will fall after overfishing. At the end of my climate model, I have a world with a higher average temperature. At the end of your tuna model, we have a world with no tuna. I fully agree with both of those. But the consequences are a lot less clear. Obviously a world with no tuna is one where I don't like the menu at a sushi restaurent as much. I want to avoid that, I see a negative consequence there directly related to the model, no other models required. What is the negative consequence of higher average temperatures? There are models showing things like more storms, higher sea levels, drought, etc etc etc. Those are definitely things we want to avoid. But those secondary models are a hell of a lot less concrete than the temperature models. We might have more drought in some places but more crop yield in others. If we have more storms obviously there is more cloud formation - won't that be a negative feedback on temperature? Those things are a lot harder to show and thats what I don't think has been sufficiently proven. We aren't really concerned with the change in temperature. We are concerned with the consequences of the change in temperature on the world's weather. That is a significant difference.