[xoxoxoBruce]

If all the knowledgeable people had a "high degree of certainty", but that's just not true.
We've hashed all the political and monetary factors involved in why certain scientists take the stands they do.
Also, the degree to which these conclusions/predictions that are just plain guessing, because most computer models are guesses to begin with.

We've listened to, "the sky is falling" predictions that didn't come true, so often, we're skeptical. Add that the proffered solutions always seem to make a few connected people a shitload of money, doesn't help.

Granted, it's logical to conserve resources, try to keep the air and water healthy. And working on reducing our dependency on foreign interests is always the smartest thing to do.