There is always "wiggle room" in science. Every field. No exceptions. That's because science can never be 100% certain about anything, ever. There's always going to be an error bar, a margin of error, a question mark somewhere. Take for example species classification. Some organisms prove more difficult than others to classify. Take for example both the giant panda and the red panda. Are they true bears or do they belong to another taxonomic family? When I was a kid back in the 80s, many biologists believed, based on the evidence on hand, that both species were more closely related to raccoons than to bears and thus placed them in the family Procyonidae. Reference books and popular science texts at the time reflected this. More recent evidence, particulary molecular studies, have since revealed that the giant panda is a true bear (family Ursidae), while the red panda has been placed in its own family (Ailuridae). While there had been some uncertainty about the proper taxonomic classification, biologists could obviously rule out what pandas were not. They were not anything other than members of the order Carnivora, the suborder Caniforma, and the infraorder Arctoidea.

Yes, there are some significant uncertainties regarding things like the degree and effects of future warming. We're not sure how much more CO2 levels will increase; it's dependent on what humanity decides to do in regards to fossil fuels. We're not quite sure how bad things will get; while it's widely agreed that more than a couple of degrees Celsius of warming will likely be a net negative, it's not certain if that net negative is "mild inconvenience" or "utter disaster." The further we project into the future, the bigger the error bars get, and the scientists are upfront about that. But there are some things we can rule out.

First off, we can rule out any sort of deliberate fraud or conspiracy on the part of scientists. Claims that AGW is a "hoax" are patently ridiculous assertions with no basis in reality. Moving past that to the actual science, climate scientists are as certain as they can be that the current warming trend is real, not an illusion, and they are extremely certain that the majority of the warming is due to anthropogenic factors, not natural factors. Scientists have demonstrated beyond all reasonable doubt that CO2 is a heat-trapping gas, and are extremely certain that increasing CO2 by x amount will have y effect on global average temperatures. Yes, there are little error bars with the temperature measurements and reconstructions of past temperatures, and the scientists are upfront about it, and while those error bars do exist, they are not off by whole degrees. Not even close. The probability that the scientists have gotten the temperature record "wrong" ("wrong" meaning "off enough to where we can't be sure if there's any appreciable warming") is extremely low. Politicians and other laymen quibbling about uncertainties and error bars in order to cast doubt on the entire field of climate science are making mountains out of molehills. Dogpiling on any and all uncertainties and obsessing over "anomalies" are common tactics with science deniers of all kinds.

Same for attacking the notion of consensus science. Many will point at the one or two papers that go against the consensus and say "I told you so!" as if every theory required 100% agreement. Halton Arp was well-known in astronomical circles for rejecting the Big Bang theory and suggesting that galactic redshift was not due to a Doppler effect, which would mean the universe isn't expanding. Unlike many who reject the scientific consensus, he had actual relevant credentials, published his research in the appropriate journals, and was respected as a cataloger of "peculiar" galaxies. But few scientists took his claims that the universe isn't expanding seriously. Cranks who reject the Big Bang theory would tell you it's all part of a plot to suppress the work of brilliant men like Arp, and that "mainstream cosmology" is perpetrating a hoax (sounds vaguely familiar, doesn't it?). But reality is far more prosaic. Nobody took Arp's opposition to the BBT seriously because he simply failed to make a good case for galactic redshift being non-cosmological. Nobody could replicate his findings, and in fact future studies ended up proving him wrong. Not only that, but the evidence for the Big Bang was so overwhelming that the odds of it being falsified were, if you'll pardon the pun, astronomically low. It's one of the most well-confirmed theories in science. It explains the available evidence, whereas no alternate cosmological models can. Arp is now dead, and pretty much the only support he has left are a bunch of yahoos on the fringes of the internet who lack any sort of credentials, have published no real research, and a huge chunk of them are Velikovsky fanboys who attack not just the BBT but a whole host of other standard theories and models is astronomy and astrophysics as well as other fields.

At the end of the day, we know that there is currently a warming trend that, as far as we can tell, is unprecedented in recent geological history in terms of overall rate (looking at temps over the past 10-20,000 years, it's like running into a big brick wall). We know that it's primarily due to anthropogenic GHG emissions (mainly CO2). Climatologists are as certain about that as astromers are about the Big Bang or biologists are about evolution. Yes, there might be a few renegades with relevant credentials that go against the consensus, but, like Halton Arp, those types never manage to get any real traction with the rest of the scientific community, and that's because nearly every other climatologist finds their research wanting for various reasons that have nothing to do with bias or politics. Mainstream theories are mainstream for a reason: They work.

As I mentioned in previous posts in this thread (including the one you quoted) people would rather attack the science, not because there's any reasonable doubt about the science, but because they're fearful of the implications of the science. Money might be lost. The government will likely be part of the equation (because it was with tobacco, leaded gasoline, and CFCs). They don't want to acknowledge the existence of the problem because they don't want to have to deal with the consequences of the problem. Plus—horror of horrors—changing the status quo is hard and takes effort. Some of them, like James Inhofe, would rather just casually charge the scientific community of deliberately perpetuating a hoax. Hopefully the deniers have a change of heart, because we should be focusing on what to do about the problem rather than pretending that there is no problem. Nobody ever said that the only way to fix the problem was cap-and-trade or what have you. Things will have to change. This change will not be free. Some businesses might lose money (and they won't be the first that lost business or had to offer different products or services because of radical shifts in the economy; when was the last time you visited the horse dealership or sent a telegram or had a milkman deliver some 2% to your house?). The problem will be in figuring out the best, most cost-effective means of transitioning away from fossil fuels. While there is some uncertainty about the possible consequences of warming, the sensible public policy approach would be to hope for the best but assume the worst. An ounce of prevention is worth a pound of cure. Not only is it better to not risk a worst-case scenario, but phasing out fossil fuels will in the long run be a net gain regardless of whether or not there was a risk of a climate catastrophe. Hundreds of thousands of people die each year from coal pollution alone. Isn't that reason enough to find other ways to generate our electricity? We have the technology to do so right now. In fact, we might not be having this discussion if the U.S. & western Europe had been getting most of its power from nuclear, which didn't happen because everybody freaked the hell out after Three Mile Island (no fatalities) and Chernobyl (a result of Soviet incompetence).

What I'm saying is that laymen debating the very validity of the science itself, with some of the detractors outright claiming "CONSPIRACY!", is pointless and unproductive. It's not much different than us debating whether plate tectonics is real or just a conspiracy to hide the "fact" that the Earth is hollow. Politics and money should never be an excuse to reject science. Just because those dirty hippies at Greenpeace are proclaiming the end of the world doesn't mean the scientists are full of shit. Just because you don't like the Big Bad Gubmint doesn't mean the scientists are lying to us. Just because you might lose some short-term profits doesn't mean you should work to sow doubt about the science. Lumping in the scientists with the non-scientist activists is counterproductive and intellectually dishonest.

What I'm saying is that we should take the scientists at their word. The world is warming, we are the cause, and there is a chance, however slight, that the warming could be sufficient over the next century to have detrimental effects well beyond the costs to solve the problem. Millions of people displaced by rising seas, crop disruptions, increase in frequency and severity of extreme weather events, ocean acidification, loss of biodiversity, spread of tropical diseases, disruption of ocean currents, loss of mountain glaciers. These problems are most likely solvable, and global warming isn't going to cause the end of civilization itself (unless we find a way to burn every bit of recoverable oil and coal in the Earth's crust), but it would be prohibitively expensive and millions would still suffer in even middle-of-the-road scenarios. The warmer it gets, the greater potential for worse scenarios and thus greater cost to adapt. It's not alarmism. It's not a plot to establish totalitarian communism. It's real science.

What I am saying is that we can solve the problem with technology we already have, and we don't necessarily have to use solutions frequently suggested by liberals. We could offer positive incentives or lend money to utilities to get them to invest more in and gradually change to nuclear, wind, solar, etc. I personally think that liberals and environmentalists bear at least some of the blame themselves for their knee-jerk rejection of nuclear power, which the data clearly shows is a statistically far safer form of power generation than coal or natural gas. Think of solving the problem as more like insurance. Yeah, you might have less money in your pockets each month just to buy something you might not ever need, but you get it anyway just in case shit happens. You may go your whole life without ever crashing your car of having a house fire or a catastrophic illness, but in the worst-case scenario you'll want that insurance. And just like how some insurance companies offer partial refunds for being a good driver, getting off of fossil fuels for electricity generation and automotive fuels would have benefits beyond preventing potential harm in the future. Even ignoring global warming, fossil fuels kill hundreds of thousands each year and cost humanity many millions of dollars just from the direct effects of pollution.

Wow you're making some big assumptions about where I sit on this issue. I am more than happy to listen to what you are saying if you hold the qualifications you claim to. Physicists are exactly the types of people I try to learn from. Just so you know I don't claim to be an expert either, but I certainly don't listen to 'anti-science' people, whatever they are.

I don't just read the assessment report by the IPCC, I also try to read as many actual papers on the subject as possible. My understanding is obviously limited, but the easiest sources of information on climate change are proving to be the least accurate (media whether right or left wing, politicians etc).

burn less coal/oil and plant more trees and we're good in about 20 years. low oil price is a sign for a less oil based future economy which is good. also, stop wasting plastic products because most of them tend to end up in the ocean.