SHRDLU is right in that buying a Prius won't hurt. We need to conserve resources to save our planet for future generations.

But using exaggerated and alarmist claims to scare people into conservation is wrong.

Even though many scientists agree that global warming is anthropogenic, some still think otherwise. These people are not "climate change denialists"; they agree that global warming exists. They're just unsure about the extent to which human activity is the cause of global warming. They believe the science is at present inconclusive and can't be used to direct policy decisions.

SHRDLU -- climatologists are as human as the rest of us. This means that they care passionately about their work. Unfortunately, this passion often makes them less than objective. And when an issue is as politically and financially charged as this one, they can lose all semblance of reason.

Science is subject to paradigms of thought and those people who think outside the paradigm are often marginalized. This happens whether or not history later proves their ideas to be correct. It's just how humans behave.

Those environmental scientists you mentioned are not immune to the political effects at work here. Young researchers especially can be denied tenure or funding if they go against the paradigm of the day. And for environmental science, the money is not "pitiful". The US spends more on climate research than on AIDS research.

So to summarize: the motivations of climatologists are not always as pure as we'd like. They care about their work, they care about what their colleagues think of their work, and they care about the money and tenure necessary to continue their work. And with a subject as complex as environmental science, this can strongly effect their interpretation of what their data mean.