I am more interested on your thoughts as to the critiques mentioned here:
The Skeptics Guide to AGW
I've posted this link several times, but have yet to see any rebuttals of the contents on this thread.
Very well. Let's begin with the definition of AGW that the author chooses to use:
Before we start,since this paper is by definition somewhat in opposition to the core of Anthropogenic Global Warming (AGW) theory, it would be useful to state in simple terms just what that theory is. The strong AGW hypothesis is roughly as follows:
1.The world has been warming for a century, and this warming is beyond any cyclical variation we have seen over the last 1000 or more years, and beyond the range of what we might expect from natural climate variations.
Already we have a problem. What "natural climate variations?" The Earth's climate has, in the past, been considerably warmer than it is now; it's also been considerably colder, and both of those have happened in the very recent past, geologically speaking. In the deep past, it's been a great deal warmer, and a great deal cooler. Given that there were no people around at any of these times, it's fair to call all of that "natural."
What would be fair to say is that, given Earth's current orbit, current axial inclination, the current observed solar activity, the current configuration of the continents (having one over a pole is almost always indicative of an ice age in progress, for example), and the state of the atmosphere aside from the gases we are putting into it, we would expect the Earth to be cooler. We would also expect the temperature to be relatively stable. Instead, it appears to be warmer than we would otherwise expect, and it appears to be getting warmer still over time. It also appears, given our current state of knowlege of paleoclimate, that it is warmer now than any time in the last thousand years, and it may be warmer now than any time in the last hundred and ten thousand years; and if it is not now, and the temperature continues to climb as we have observed in the extremely recent past, a century or so, then it surely will be warmer than any time in the last hundred and ten thousand years.
2.Almost all of the warming in the second half of the 20th century, perhaps a half a degree Celsius,is due to man-made greenhouse gasses,
particularly CO2.
First, this ignores the hiatus around and after WWII, caused apparently by the injection of sulfates and other aerosols into the atmosphere in large quantities. These aerosols artificially suppressed the temperature for a period perhaps as long as thirty years, up until the 1970s when pollution laws began to be put into place to deal with them. As a result, the first twenty years of the second half of the 20th century represent a statistical anomaly that is being ignored by this statement.
Second, CO2 is the largest individual contributor, but may not be as much as half of the problem. Other gases also have warming effects, and many artificial gases have been released that have strong warming effects, primarily chlorofluorocarbons. Methane is also a strong warming gas, and as the global population increases, and as the standard of living increases and more protein is consumed, more methane is produced for a variety of reasons. It is all of these together that are creating the problem, not CO2 alone.
3.In the next 100 years, CO2 produced by man will cause a lot more warming, from as low as three degrees C to as high as 8 or 10 degrees C.
Again, CO2 is not alone. It is merely the majority culprit. There are other things that will have their own effects, and they also will most likely need to be dealt with; CO2 is merely the highest nail, and therefore gets the hammer first.
4.Positive feedbacks in the climate, like increased humidity, will act to triple the warming from CO2, leading to these higher forecasts and perhaps even a tipping point into climactic disaster
Hmmm, a nit-pick; that's "climatic" disaster. "Climactic" refers to a climax, not a climate. Other than that, I don't see a problem, but I'd like a lot more specific statement of what precise feedbacks are involved here. There are feedbacks ranging from environmental, to climatic, to physical, that we know about- and doubtless yet more we do not. I think it is a vast oversimplification to limit the discussion essentially to a single specific feedback.
5.The bad effects of warming greatl outweigh the positive effects,and we are alread seeing the front end of these bad effects today (polar bears dying,glaciers melting,etc)
It is entirely possible that we are already seeing an effect on the salmon catch from this, and that's quite a lot of protein that might not be available to eat soon if that's correct. The effects extend a lot further than polar bears and glaciers, right into your local supermarket, if that's the case. I'd like to see a much more realistic evaluation of what we may be talking about, in terms of food people eat every day, rather than far away polar bears and glaciers. This strikes me as propaganda.
6.These bad effects, or even a small risk of them, easily justify massive intervention today in reducing economic activity and greenhouse gas production
First, I don't see why economic activity has to be reduced to accomplish the goal of greenhouse gas reduction. Second, I don't think a fair review of the potential effects has been done here, and I don't think it was in the body of the document, either; screw polar bears and glaciers, let's talk about the supermarket and your dinner table. Third, I object to "easily" as propaganda; such a decision cannot be "easy" in any sense of the word, even if the effects were to be as dire as this individual apparently intends to make them out to be. Fourth, it's not a small risk any more; serious economic consequences loom on the horizon right now no matter what we do. The question now is not, can we avoid it, but rather, how bad is it going to get.
I don't see any sort of objectivity here. This just looks like another denier hit piece to me. I could go on and dissect the science, but why bother? It's obvious that with this start, it's going to be filled with misrepresentations of real science ("primarily CO2," "small risk," "polar bears and glaciers"), propaganda, and overlooked evidence. If I thought that the author would respond to criticism I might take the time; I don't, based on what I see here. The entire goal of the piece is not to promote skepticism, but to spread more propaganda and provide cover for people with a political agenda. That political agenda has gotten us to the point where the Arctic Ocean damn near melted entirely this past year. I see no point in playing this political game further; my response is now, "that's woo," just like when someone tries to stuff Jebus or crank physics or homeopathy up my nose.
