3. What is wrong with warming?
There is another type of scientist besides those who doubt AGW who are often labeled skeptics (or deniers). These are those scientists who believe we are probably warming the planet, but that it won't be such a bad thing. There beliefs differ, but in general we can say they don't believe temperatures will get high enough fast enough to do any damage (and might be beneficial), that increased levels of CO2 might be good, and finally that many of the assumed problems which are theorized to occur as a result of AGW are based on bad science (e.g. increased dangerous weather, famines, etc). To put it simply, these scientists believe we are warming the planet but either it isn't going to be a problem or it isn't going to be enough of a problem to warrant any drastic measures.
4. The politics
The more political the issue, the less reliable the academic system for reporting and publishing research is. Global warming is extremely political, and there are several reasons to think that a lot of research which contradicts AGW theory is ignored, not funded, discouraged, etc.
First, apart from groups on both sides of the political spectrum which fund research (e.g. environmentalists or right-wing think tanks), the vast majority of research money is from governments. This means a couple of important things. First, governments don't fund (or at least not a lot) scientists or labs who research things which aren't problems (e.g the person or lab working on a cure for cancer is going to get a lot more funding a lot easier than a person or group researching hunting patterns of sharks). This means that there is a big financial incentive to maybe add some dramatic "coloring" to the published research, or perhaps ignore results or evidence which doesn't fit with the hypothesis being investigated (if it supports AGW). It also means that labs which want to continue to get funding are under pressure (probably not intentional) to release studies showing that there is a problem. Now, I'm not saying that most (or even any) scientists or research groups are fudging data and forging results for money. It's not like they are getting paid a lot. It's simply that, explicit or no, there is a pressure both at the government level and at the administrative level (of the various labs) to report dangers rather than "all clear." And anyone who has knowledge or experience with getting grants and funding for projects knows it is very competitive and there are a whole lot of people out there with doctoral degrees barely making any money because the subject they are researching hasn't generated a lot of interest.
Second, there is the issue of politics in academia. I've spent a lot of time teaching at the university level, studying at the university level, attending conferences, interacting with professors, etc. In Europe and in the US, the two biggest (both in terms of money and extent of research) places for climate research, the vast majority of those working in universities are politically left of center. Now, again this doesn't mean researchers are fudging data to further a political agenda. But bias creeps in everywhere, and it can certainly have an effect. One of the biggest issues is what research is being done. For a study to be undertaken, the researcher or researchers first have to come up with a subject of study and a hypothesis to test. If most researchers tend towards the left, and therefore are more likely to tend towards environmentalism, they are more likely to come up with research topics and hypotheses which look into how humans are influencing climate rather than how natural forces are. This is VERY important, because it not only relates to the first point about money above (if the warming is natural, there goes most of the funding), but also because the climate is immensely complex and difficult to study. Focusing on human actions is easier and their effects is easier than trying to accurately model all of the natural variables and their interactions which are part of our climate system.
Third, I'd like to take a bit of time to mention the hacked CRU emails, and the constant battle both professional and amateur researchers have had getting access to raw data and codes. The emails are extremely interesting because a lot of what they relate to has been discussed by both sides of debate for many years now (the hockey stick, getting access to data, the back and forth between certain researchers, etc). The CRU emails show some of the behind the scenes work, thoughts, and exchanges that major climate scientists were engaging in, which include refusing to release codes, admissions in private that public research like Mann's hockey-stick had errors, attempts to evade FOI requests, and so forth. Most importantly, they portray lead researchers determined to get their side out there and actively prevent the other side from being heard. They display not a scientific, objective view of the issue, but an emotional one. This isn't the place to get into detail, although perhaps I will start another post which goes over the history behind the emails, the emails themselves, the various inquiries, and so forth.
Finally, many skeptical scientists have complained that even when they manage to get funding for studies which do not support AGW, they are met with refusal after refusal by various journals to publish these studies, or (at the very least) they are asked to take out statements or soften statements which explicitly contradict or put into question aspects of AGW theory. Now, it could (and has been argued) that this is because the studies were flawed or simply not good enough, but there are several indications this isn't the reason. The most important indication is the quality of some of the AGW research which DOES get published. For example, just recently the IPCC (the largest and most important group of scientists when it comes to public policy) had to wipe a lot of egg off of their faces because of their latest report. It is important to understand that the IPCC doesn't do any research. They are a massive group of scientists responsible for reviewing the scientific literature on climate change and publishing findings every 6 years of so based on that research (the issue with IPCC policy, leadership, and so forth are issues for another post or thread). In the most recent report, several ridiculous errors were made despite the supposed extensive system of checks in place prior to publication. In one instance, they published a graph of the estimated financial cost of global warming as if this was part of the scientific literature, when it turned out one scientist in particular without doing any research drew up the graph as a guess and sort of sent it around informally. He recently admitted this and publicly stated the graph shouldn't be included in the IPCC (I need to point out that I don't believe he had anything to do with its inclusion). Another publicized error was the inclusion of data concerning drastic effects of AGW which came not from scientific literature but from a tourist pamphlet. Outside the IPCC, when we look at the peer-revied journals, we find the same problems. To use just one famous example, the one thing that is beyond reasonable dispute is that Mann's famous hockey-stick graph, which was featured prominently all over the place, and consisted of two separate publications in a peer-review journal, and was featured in the second to last IPCC report, was never really checked by anyone. That is, no one ever bothered to look at the raw data, the methods, or the codes used to generate the graph. Also, it is widely accepted (and even Mann published some corrections) that the graph was flawed. While some still argue that the flaws don't matter much, apart from the peer-reviewed and published criticisms, two separate panels investigated Mann's work. While Wegman's panel was very critical, and the NAS less so, both agreed that there were important errors and that the conclusions of temperatures during the MWP were questionable.
In other words, here was a graph touted all over the place that had numerous errors. And it isn't alone. One of the papers Mann has continued to cite (even before it was published) to support his methods, by Wahl and Amman, was continually asked to be corrected prior to publication, and even though when it was finally published it included statistical results which indicated the findings were insignificant, the study was published anyway. Basically, it is hard to believe that while many papers supporting AGW pass the peer-review check system and contain important errors (I need to note here that this by itself doesn't indicate anything; peer-reviews are usually very thorough and most submissions across fields are rejected or require revisions), so many leading scientists and experts complain that it is becoming more and more difficult to publish research which questions AGW theory. The combination of the difficulty obtaining funding/grants to research topics which might contradict AGW, the pressure from both government and research groups (e.g. universities, labs, etc) not to research such topics, and the difficulty (when researchers manage to overcome the first two problems) of finding a journal which will publish research which contradicts/questions AGW theory means that there may be a great deal more evidence AGAINST AGW theory that isn't coming out for one or more of these reasons.
, guess I should have checked some of the past global warming threads first though lol.