Being unpredictable, the conservative approach would be to look at worst case scenarios. So far I haven't heard much and would be interested in these predictions as well.
No, the conservative approach is to look at past extinctions and see that there is little or no impact. Too many extinctions in too short of time may have different results, but the environmentalist whining is just plain irrational.
It doesn't seem irrational to conclude that we live in a complex system that we don't understand and accelerating changes to this system, due to unprecedented human population and capabilities, could affect human survival. Ignoring risk isn't a conservative approach.
