The marked difference of time frames is obviously not a testament to faulty science. Rather, it shows the disparity of social, political and intellectual maturity between the two cultures - something we need to rapidly come to terms with here in the western hemisphere.
But beyond our low population density and wealth of resources there is a more insidious problem, namely our puritanical inability to accept rigorously tested and overwhelming scientific evidence that demonstrates our environmental impact. In European terms, our hysterical opposition to scientific facts on climate change is eerily similar to 1633 Florence, where the Catholic Church imprisoned Galileo for demonstrating that the universe revolved not around the Earth, as religious scholars maintained, but the Sun. In much the same way, Bush and the bishops of big oil actively seek to sentence those advancing scientific evidence for global warming to a social and professional exile - Hansen being one of many whose work was silenced or heavily edited by Bush officials.
Perhaps this isn't surprising. Since the time of Galileo, Europe has moved through centuries of scientific advancement, been home to two world wars, and witnessed the decline of their colonial empires. Both psychologically and economically, they have been required to face the reality of multiple cultures competing over shared resources, and have learned to work with others to protect resources for a shared prosperity. North Americans and Australians by comparison are still playing in the sandbox of the global social world, holding tight to what they believe to be 'theirs' and being unwilling to negotiate beyond that.
Granted, Europe has had nearly 400 years to mature since the days they locked up their scientists as heretics, but as the experts above have said, we have just 4 to 10 years to get this job done (depending on what level of maturity you are ready for). Now would be a good time to brush the dirt off our trousers and take a seat at the grown up table. Leaving our fantasies back in the sandbox and recognizing the scientific evidence for global warming is one place to start.