It is scientifically beyond reasonable doubt that humanity is having a tangible negative effect on the global environment, and that this effect is causing changes in the climate which will, in the near future, cause catastrophic habitat destruction.
Only a person who has blind faith in "authority" and no understanding of actual temperature data would make such a statement. Study the actual data - how it is collected, what the error margins are, what the method substitution effects are, how it is adjusted or unadjusted for local phenomena that don't reflect temperature globally, how it is affected by the various natural cycles that exist in this solar system, what we know or don't know about those cycles, etc, etc, etc. Aside from all the institutional pro-alarmism bias that you will inevitably observe, the only conclusions you will be able to draw from that data is that there are no conclusions to be drawn. "We don't know" is a phrase that scientists should say more often, but unfortunately that phrase does not bring home the bacon.
Furthermore, your premise is based on what amounts to the belief that "environment" or "habitats" are self-owning entities whose "rights" supersede those of humans. Human beings own the "environment", including all other plants and animals in it - not the other way around! The concerns about human beings violating each-other's Rights through pollution are relevant, the concerns that "Mother Earth has a boo-boo" are not. You are sacrificing humanity on the altars of gods that only exist in your imagination!
There is literally not one single national or international scientific body that denies this (a few remain neutral, but NONE deny it).
Name one "national or international scientific body" that doesn't receive a penny of government funding, directly or indirectly, and is immune from government force.
The libertarian approach ignores externalities - no cost is assigned to long term damage suffered by people other than the economic actor, and thus massively, dangerously undervalues pollution.
There is not one unified "libertarian approach", but no libertarian / capitalist approach I've ever heard of ignores externalities. The whole point of the growing field of free market environmentalism is to quantify externality liabilities of each polluter and the restitution entitlement of each victim! Even the most radical Anarcho-Capitalist approach merely over-approximates the damages, which I agree is a problem because only the most direct victims of pollution would be able to sue for damages, while a person who receives small amounts of pollution from each source will not find it economically viable to sufficiently prove damages against any particular polluter, but it doesn't matter that all victims join the lawsuit, just that enough of them do to make the polluters pay and make cleaner technologies ever-more economically desirable. If a government can claim to represent hundreds of millions of people just because they were born between certain arbitrary lines drawn across a continent, then why can't a legal institution represent the interests of as many people if they all explicitly filled out a form claiming that their property receives pollution from a specific source?
Furthermore, as technology progresses, the gathering and analysis of air, soil, and water samples will become ever-easier. Remember that you don't own the air rights over your terrestrial property out into the universe indefinitely, just a certain amount of altitude to put a safe distance between you and any fly-over traffic, which means automated probe-bots will be able to hover over power plants / factories / private highways / other major sources of pollution, take air samples, and model the flow of harmful particles through other people's property with ever-greater precision. Quantifying pollution destination data will be even easier than quantifying the origin, because the alleged victims will own the property and be able to subscribe to the services of multiple competing pollution monitoring agencies on the basis of their reputation and past legal performance. Individual homeowners probably won't bother with this, but interests like homeowners' associations, local business alliances, and charter cities will be able to band together for a common legal cause. This will inevitably lead to preemptive legal agreements between major polluters and their neighbors, leading to polluters capping their emissions, paying certain predetermined fees for excess pollution, supporting local parks to offset their liabilities, etc.
No libertarian / capitalist approach is perfect, but the socialist approach is substantially worse. Much of the world's pollution comes from government-related activities, and governments are able to limit the liabilities of the big polluters while using pollution regulations to hurt smaller businesses and make the marketplace a lot less competitive.
This is absurd. You cant claim to have science on your side then deride the established findings of the entire world scientific community (including such groups as the US Petroleum Geologists!) as suffering from institutional bias.
The
American Association of Petroleum Geologists (AAPG) was recently bullied into softening their criticism of the global warming hoax, but they have not jumped on the alarmist bandwagon as your repeated mention of them might lead a casual reader to believe. Details are important - like I said, no one is denying that human beings produce heat and pollution, it's just a matter of relative quantities and consequences. There is a lot of money to be made through government-sponsored global warming hysteria (just as programmer greed contributed to the Y2K hysteria), but this time there's a lot to lose by not marching with the herd. That however does not strengthen the non-existent scientific justification of the alarmist's claims. Faith, emotions, hype, money, and power don't add up to proof!
Furthermore the potential to profit from the new legislation is VASTLY dwarfed by the potential profit of industry groups if the legislation is abandoned.
No, the incentives are often vastly dwarfed in the other direction. You must remember that oil companies aren't married to oil and coal companies aren't married to coal, they can easily diversify, and there will be plenty of government hand-outs to help the most politically-connected ones do precisely that, or to gain exemptions from the new regulations which will destroy their competition. Companies don't have a choice of which universe they operate in, this universe where trillion-dollar criminal enterprises called governments are embracing "global warming" wholeheartedly, or an alternative universe where reason and scientific skepticism prevail. They know the government-sponsored lie will win out, at least for a while, and they are positioning themselves to maximize their profits and limit their liabilities as much as they can.
I dont believe it will cause catastrophic problems in the next 20-30 years, I think it will be more like 80-100.
I think 80-100 years from now the number of plants on this planet will double, thousands of species will be cloned out of extinction (and many new never-before-existing species created), and pollution levels will be as they were in the 17th century.
The point is that if we dont do something now, it may be too late. Even if there is a possibility we are wrong (and I dont think it is possible), we cant afford to take the risk - a switch to a more sustainable world economy is never going to be a bad thing.
Ah,
"the final proof will come in the form of mushroom clouds"... Be afraid, people, be very very afraid! Don't look at the fact that the 1 degree per century of past temperature change is fully explainable by new asphalt and construction around the weather stations! Don't think! Panic! Obey! 
And ain't it funny how the crisis remains "X years away" as decades pass and X never changes. Wasn't the 1970s "our 'last chance' decade", and then the 1980s, and then the 1990s... And wasn't year 1995 supposed to be peak oil? Etc, etc, etc. No matter how many times they are wrong, the alarmists never let scientific facts get in the way of politically convenient hype!
How is this an argument against gasoline tax / pro-environment legislation?
My apologies - I was multitasking and didn't notice that I didn't fit all of my thoughts into that paragraph. I edited it a bit later, but it seems that you replied before then. If you have to tax something then gasoline (as well as vices like drugs) are a better choice than some of the other possible taxes, but it merely sticks a band-aid on a bullet-wound while ignoring the underlying problem.
