When it comes to global warming I've always been fairly skeptical of the claims made by the econuts believing that they were guilty of "Suggestio Falsi" and "Suppressio Veri" and over the last year or two my skepticism has increased by leaps and bounds. There are a few reasons for this, but they all boil down to concerns about the underlying data, concerns about the processing of that data and concerns about the religious fervor of many of the more vocal proponents. Below I'm going to list problems I see in all phases of the climate debate starting with the raw data and ending with the proposed solutions.
We'll start with the data. As noted particularly by Anthony Watts at his Surface Stations site and his "How Not To Measure" series, it is clear that a lot of the raw data is, to put it kindly, less accurate than it might be. Indeed some people end up using data from stations that don't exist any more by deriving the data from those of surrounding stations. This may or may not be valid from a scientific point of view but it does quite a bit of damage to the statistical analysis because the assumption that the data from different stations is independent is no longer valid. All these examples are in the USA and lest this look like a bitch about US data gathering I think it is worth noting the Urumqi glacier and various discussions of stations in Peru.
This leads us to problem two. The munging required to strip out noise and errors from the raw data is a process that seems to me to be based on some highly questionable assumptions. One sub-problem (noted in the Peru link above) is that the computer program(s) make some odd assumptions about whether a station is rural or urban and their detection of station moves and changes also seems to be a little iffy. There are other related issues such as the way that loss of a couple of days in a month will result in the entire month's worth of data being thrown out and replaced with an average derived from adjacent stations and so on. In the paleoclimate field the data adjustments are even more dodgy and, despite the fact that a lot of work has been done to get the analyses right, many of the premises behind the conversion of (say) tree-ring data to annual temperature look to be seriously flawed. And then there is the dangerous (mis)use of statistics and statistical techniques that led to the infamous "Hockey Stick".
Perhaps because of the fact that the data is iffy and the calculations complex we run into problem three which is the surprising secrecy that surrounds all sorts of climate research. The fact that Steve McIntyre and others are facing such a run around when they try to rerun the calculations of GISS et al automatically raises a big red flag in my mind. The point here is that the same people who seem to claim that releasing their data, source-code etc. would raise intellectual property issues are the ones who are getting on TV and telling us all that unless we repent we're all going to die. A number of people have noted that this resembles how conmen pushing stock scams operate. I agree but I also note some consistency issues. If we're all going to die then that is surely more important than whether someone's IP is infringed upon. Would it not be more important to get more researchers to analyse the data and figure out if we have 5 years to act or 15 or whether we're all doomed anyway (and if so what we can do to best mitigate our doom). The Climate Skeptic calls this "post-modernist" science and, like me, he clearly doesn't think much of it.
Then we come to problem four which is the accuracy of the models. Given problems one & two above (and what one can reduce from problem 3), it seems likely that the climate models are going to be less than accurate even if they have the right theory behind them. And indeed Lucia and Steve seem to show that the last 10 years are making many of the more dramatic predictions from the 1990s less and less likely to be true. This doesn't mean that global warming isn't happening but it certainly looks more like some sort of regression to mean and/or that a cyclic phenomenon (e.g. solar cycles) is overshadowing the very long term trend. There is a lot more here, suffice it to say that the temperatures in the tropical troposphere are really not doing what most of the climate models think they should do. CO2 in particular doesn't seem to be quite the problem some think it should be which leads us to problem five.
Problem five is the question of whether climate change is caused by humans or not and the related (but separate) question of whether we should try to reverse it. The big problem here is that thanks to problems 1-4 we're arguing ahead of the data or at least making arguments based on data which is questionable. It is at this point that we can bring in the economists. As the Skeptical Environmentalist, Bjorn Lomborg, has written, even if climate change can be fought, the fight may cause so much economic damage that we would do better to come up with ways to live with a degraded environment. He is not alone, this letter to the EPA (not directly concerning climate change) points out, leading economists strongly recommend that cost benefit analysis be done before environmental rules are passed. I should point out here that I'm all in favour of finding alternatives to oil/gas but that is because I want to see an end to the power of the mad mullahs and nationalistic tyrants who seem to produce the majority of the world's oil/gas. Whether such a change effects atmospheric carbon dioxide or not is a relatively minor issue.
Finally we arrive at problem six which is the alternate energy series of boondoggles. Just as it makes sense to avoid passing environmental rules without cost benefit analysis it also makes a lot of sense to do such analysis of the different alternate energy scenarios. If you do that then you realize fairly quickly that the best way to cut fossil fuel consumption is to start burning uranium and that windpower and current first gen biofuels are pretty much the worst possible ways to do it. This no doubt explains why governments all over the world are subsidizing biofuel and wind turbines....
All in all the whole global warming/alternative energy drive by environmentalists is looking more and more like a scam, a scam that governments are happily supporting because they find the idea of carbon taxes to be a great way to raise tax revenue without complaint from the voters. Unfortunately for the governments and the environmentalists the poor foundations of their global warming alarmism are becoming ever more clear. It may not be long before some folks in Scandinavia are asking Mr Gore to give his prize money back.