I don't think there's any real doubt that climate change is occurring. Of the ten hottest years on record (over about 180 years), 6 of those years have been since 1995.
What IS in doubt is the following:
- How much of this warming, if any, is due to human activity?
- Is this warming just a temporary "warm spell" or a long term trend with little/no end in sight?
- What are the long term consequences, if any?
- What, if anything, can humans do to alter or change these consequences?
I don't think there's any real consensus on any of the answers to these questions, and those are the ones we need answers on more than anything. There are plenty of credible hypotheses, models, and sometimes outrageous forecasts. Much is little more than outright fear mongering by scientists trying to make headlines and score grants for their research. Some is even politically motivated. There is really no way to know who to believe, even if their intentions are honest, some of their models may be flawed. We can't predict weather patterns accurately for more than a week in advance, there's no way you can convince me that some computer model will be able to tell me what the climate will be like in 100 years, or even 30.
Without knowing the causes, and the effects, and the scope, of the problem, how can you say people NEED to act? And if so, how can you know WHAT they need to DO? There are numerous possible "natural" explanations for increases in global temperatures lately, including increased solar activity, termite-based methane emissions, and countless other competing theories.