And most of this scientific consensus seems to be all based around the IPCC, an organization for which the entire point of it's existence is to find evidence of climate change. Frankly, even if there is a consensus I'm not sure it matters... just because a minority of the scientific population doesn't agree doesn't immediately mean they are wrong. Keep in mind that there have been similar instances of the majority being wrong in the past.
The IPCC is a massive literature review, probably the largest ever undertaken. As such it simply reflects scientific opinion on climate change and acts as a single point for accessing all the major literature relevant to the topic. It’s one sided because the source literature is one sided.
Go back to the first page in this thread where it’s explained:
1) CO2 does allow visible light to pass through untouched.
2) CO2 does absorb certain frequencies of the thermal radiation emitted when that visible light hits the earth
3) Those frequencies are in bands and locations where that thermal radiation would have otherwise escaped into space
4) We are dumping massive amounts of CO2 into the atmosphere
5) Thermodynamics tells us this must result in higher surface temperatures.
There is very little room to dispute any of this, so at best you can argue the degree or warming not the warming itself. We can observe warming actually taking place and the degree of warming is in good agreement with the predictions being made. This is just about as rock solid a case as you will get in any scientific endeavor. Yes there is always the possibility it will be overturned, but that’s the case with any science.
To overturn it you’d need a couple of things. First you’d need to demonstrate some previously unknown phenomenon to counter the known warming effect of CO2. Second you’d need to come up with an alternate explanation for the warming that is taking place. Neither of these has appeared in a viable form in peer reviewed literature
Well... follow me on this here... I'm going to try to use a bit of logic:
First, we know that there has for several tens of thousands of years been an 800 year gap between temperatures rising and CO2 rising.
From this, we can discern that there was something non-CO2 related that triggered the Earth to warm. Have we even figured out what that might be other than natural cycles of the sun or volcanos temporarily cooling the earth (in the case of it getting cooler)?
Why are we so quick to throw out such a long history of climate change for the sake of what's happened in the last 100 years (if that!)? There might be very important things in there that we are missing and if we don't know what caused the climate changes back then, how can we prove that those same factors aren't causing it now and making the CO2 appear to be the main factor as the AGW people are suggesting?
Also, considering that there is this 800 year lag there have been times that CO2 has been high without sending us into some sort of constant spiral up in temperature like scientists are saying it will now... if this didn't happen in the past at one point there had to have been some sort of negative feedback to keep the climate from getting stuck in a constant positive loop of warming.
I believe most thinking is that initial warming is triggered by regular variations in the earths orbit. This warming reduces the oceans ability to hold CO2, and the resulting release acts as a positive feedback driving up temperatures until they once again hit a stable point.
The current warming doesn’t fit with this historical pattern on two fronts. First, the going by the history we should be approaching another cooling cycle in the next few thousand years not a warming cycle. Second, the CO2 rise is occurring before the temperature rise suggesting that the mechanics behind that previous change doesn’t apply here.
It’s also worth pointing out that the earth was undergoing an upward spiral of temperature during this period, and while positive feedback effects like rising CO2 and decreasing albedo due to ice retreat didn’t start the process there is every reason to believe they played a major role in making the temperature swing as large as it was.
Another thing that concerns me are the accusations that it is difficult to get access to some of the methods and data from some studies used in the IPCC reports. I'm not sure how true this is, but if people like McIntyre are truly having difficulty getting very important pieces of information like how Hansen adjusts data from temperature recording stations, I immediately become a bit concerned. Science should be about openness and discussion, right?
Since it is a literature review, the source information comes from the original papers. IMO McIntyre is seriously misrepresenting the openness of the process. The raw data in publicly available, the methods being used are documented in the relevant papers in sufficient detail to reproduce the work.
After these things were pointed out McIntyre moved onto “but the code isn’t available”. While there are cases where making the code available is desirable it certainly isn’t required. The point of peer review is to allow independently reproducing the results. If you use the same code, you get the same errors and you haven’t really accomplished anything.
What McIntyre is really looking for is the look over the shoulder of every researcher whose results he doesn’t agree with and to tell them how to conduct their research. He’s looking to make a nuisance of himself. The code Hansen is using can apparently be replicated with “two pages in MatLab” which is nothing. A decade ago as an undergraduate I had bi-weekly projects that required as much.
Rather then doing this work for himself, however, McIntyre wants to “review” Hansen’s work so he can say “look Hansen was wrong!” without ever having to provide a correct result of his own. The corrected result McIntyre doesn’t want to produce would almost certainly still support Hansen’s claims. IMO this makes McIntyre's motives very suspicious as it's far more spin then science.
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. Life is not that simple.