Not.
I encountered this sign today at lunch when walking past a bunch of environmental protesters. I agree totally with their intentions, but this particular message is just wrong.
The earth (if sentient) is just about waking up and wondering what we are – the whole of human history and pre-history (the bits that weren’t written down) is no more than a blink in the eye of the earth. If we successfully cause an extinction-level climate change event (and so far it looks pretty successful), our entire extinction will be just another layer in the geological record – just a bit more unusual than other thin extinction layers.
The earth will quite happily get used to a warmer (or colder if it eventually settles down that way) climate equilibrium and might just (if sentient) wonder where we’ve gotten to.
The earth will go on without us; barely noticing we were here.
We’re not a plague on the earth; we’re a plague on our children.
And when you come down to it, the slogan “We Are A Plague On Our Children” is far better – it’s accurate and more personal, and harder hitting.