1) The big oil conspiracy is out in the open. They're out to make money, and they've relatively little regard for the environment at large and the long-term prospects for it. They only care insofar as the government forces them to. The penalties for violation are fairly minor. Large corporations rarely have a sense of long-term perspective, and the oil companies know that their long-term prospects are inherently limited (oil will eventually run out), so they need to make money now while people are still willing to buy it and they can get to it so easily. Big Oil subsidies in North America are well known. Somehow, they're still getting tax breaks and incentives from governments despite the massive profits.
2) The predictive power of the models isn't exact, but that doesn't mean it's not sufficient to act on. Long term climate analysis is hard, but for our purposes, the problem isn't intractable. Think about it this way: I can already predict the climate with sufficient fidelity to know what clothes I should be putting at the front of my closet in December of 2015. The fact that I won't know the day-to-day temperatures or whether there will be wildly anomalous days where it's freakishly warm aren't relevant: December of 2015 in Canada will be cold, like it always is. (I can't predict what it'll be like in 2050 just yet, but it's almost certainly still the case that it will be colder than July 2050.) The science is better than you think it is, I reckon.
3) Some of the catastrophes are somewhat beyond our ability to fix or adapt to, for a variety of reasons, and most of them have to do with greed or fundamental undermining of the system. If you're talking about ocean acidification, for instance, it's really hard to undo. Jellyfish are taking over the oceans because we've fundamentally overfished them and upended the ecology. We're likely to see the collapse of several fisheries, and those take a long time to recover. With the added pressure of climate change, we might not see those species recover, and that means a huge portion of the world will lose an essential protein source. We're doing incredible violence to a lot of systems, and it may have been possible for them to survive them well enough, but we're hitting them on a lot of levels simultaneously. If climate change due to CO2 emissionswere the ONLY problem, I might be a little less worried--we could plant more trees, or change our farming methods, etc.--but we're in a bad spot where we've given ourselves no room to manoeuvre. Technology and science will help, but only if we sit down and believe in what the science is telling us and move to fix the problem. Deluding ourselves into rejecting the problem out of hand means that it CAN'T be solved.