[sojournerc]

Beware of availability bias here.

Bad news is reported far more often than good.

There are signs of the planet greening as a result of higher CO2, for instance.

That doesn't diminish the potential damage, but it's not all bad.

[diveanon]

The largest mass extinction in history was due to rising 02 levels.

Its the rate of change, not the change itself that causes mass extinctions.