Warren over at Coyote Blog has written an excellent wrap up that summarizes the skeptic’s issues with the anthropological cause of global warming. It’s still a work in progress, but all of the “data” is there. My skepticism has always come from the statistical realm, all of the data and models I have seen are a mess, and the CO2/warming trends only match reasonably well if you are really lenient and ignore about 40 of the last 100 years. It’s one thing to eyeball a regression or correlation and think it’s pretty close only to find the data doesn’t fit. It’s quite another to eyeball a regression or correlation, realize that it doesn’t fit at all, and then futz with the data until it sorta, kinda works. Mann’s “hockey stick” has been entirely discredited thank God, it wasn’t even mentioned in the last release of the UN’s report even though it figured prominently in the previous version. That was 5 years ago.. settled science my ass…
Warren also brings to light some other interesting facts such as:
CO2’s effect on the atmosphere is one of diminishing returns. Co2 can only raise the temperature by about 1.5-2 degrees celsius. All of the other temperature increases in the various models are ascribed to “positive feedback” mechanisms that so far no one has been able to predict or even demonstrate that exist. The earth has been warmer in the past, and yet these positive feedback loops did not kick in and turn the earth into Venus.
In addition to assuming positive feedback loops, there is the assumption that there will be no negative feedback loops despite the fact that stable systems tend to (and always have) lean towards negative feedback systems. Water vapor is a prime example. Water vapor is much more efficient as a greenhouse gas than CO2 is. If a lot of water vapor is put into the atmosphere, it will cause much more warming than CO2, assuming that it doesn’t form clouds instead. Clouds are a negative feedback process, they tend to cool the earth. Negative feedback is not included in any of the models used even though they are much more likely than run away positive feedback…
The amount of CO2 in the atmosphere has indeed increased, from .0280% of the atmosphere before the industrial revolution to a whopping .0378% currently. That would be less than 4 one hundredths of a percent. As he says, if you were taking a trip from LA to NYC, .0378% wouldn’t get you off the runway at LAX…
And there’s a bunch more, alternative models that show at least as much correlation as the CO2 models and in some cases much tighter fits, measurement issues, econometric issues (The UN used a calculation that assumes that North Korea, South Africa, Libya and Turkey will all have a higher GDP than the US by 2100. They estimate future CO2 production on these figures. It’s safe to say that they’ll be a ways off…) and more.
“But Isaac, isn’t the downside significantly large to just be careful?” It has gotten to the point that not only would I have to be wrong, but the the overestimated worst case scenario would have to be off by a factor of 5 or more for any of us to worry. The UN’s worst case by 2100 is a 15-17 inch rise in the sea level. What people (at the UN and elsewhere) are purposing in order to “fix” this would stop the economic progress of developing countries (China and India are on the cusp of breaking out of the crushing, lethal poverty that they have been caught in for centuries) and hold us way back from where we would be otherwise. As wealth grows so do life spans, peaceful relations, and yes, even environmental quality (would Brazil cut down more rain forest if it were wealthy or if it were poor?). In my opinion, people either have total doomsday scenarios in mind that are totally unfounded, or they really don’t understand the cost that would be required in order to deal with it. Or maybe both…
I have sent this paper to two of my readers that have told me that they don’t agree with my skepticism, if anyone else wants a copy, let me know and I will forward it to you.