This is a subject matter that I have some knowledge and experience of. During the 4 years of my Ph.D. I worked to develop methods to locate extremes in climate data (heat waves, mega tornadoes, etc), and I could put my hand on my heart and say there are some very disturbing things going on with the climate. Now before you colour me as some ultra left-wing socialist who spends his time split between climbing up trees and working for trade unions, I must say when I started the research I did not care about the climate, it was all just numbers to me, and I remain one of those people that prioritize humanity over climate, flora or fauna.
There have been a host of high profile people who have come out saying that they 100% believe in global warming. I'm willing to say that I'm far from 100% happy about the predictions and models used to aid these arguements. There is some evidence that the trending observed in global warming may be partially caused by the expansion of villages, towns, cities and the changes in farming practises over the last few centuries. I have also been privy to an excellent presentation by one Professor to some of the authors of the IPCC report and he demonstrated that models used to predict global warming were unable to predict Iceages. The standard way to test a premise is to see if that premise is able to explain things that you know and so if a model is unable to predict the past then how can it be expected to reliably predict the future?
What I would be 100% happy saying is that global minimium temperatures are increasing and that they are increasing by a non-trivial amount. This may sound far more innocuous than the planets temperature jumping by 6 degree, and who doesn't mind less chilling winters, but it has a dramatic effect on the occurence and recurrency of extremes. These slight changes in mean are demonstrated by Wiglely (Nature) to change a one in twentyfive year (extreme event) into once in five years and the once in a century becomes once in eleven years. Drought, floods and heat waves, all happening on at a much higher frequency and much higher severity, and it is this that provides a clear danger to people lives and well being in both the developing and developed world.
When a serious extreme climate event happens all we can normally do is pick up the pieces - such as famines in Africa or the communities and industries ruined by flooding in India. Planning for it can be attempted (ish) but facilities, protection or plans, for such extremes, have a habit of standing around for several years looking like white elephants and when they are called into action they tend to be inadequate as the extreme that they were designed for were milder than the one which occurred. As the UK encountered with Snow last Winter: a lost £13 billion in revenue and some life and limb.
Schemes, such as carbon capture, are cheap in comparison to the expense of allowing climate extremes to ravage our weakened economies and that's excluding the potential additional expenses caused by a significant increase in global temperatures. Even though there may be some short term hardships for pursuing green agendas, they must be pursued as there is no cheaper credible alternative.