//The cost, ultimately, being extinction? //
of us, yes. human activity may lay waste to large parts of the planet, but won't destroy it. enough other living things may end up being destroyed that human life becomes unsustainable, but its very unlikely to kill everything. once humans have gone, nature will begin to set things right. it might take millions of years but that is but a blink in ecological time. the planet doesn't need saving; it's our lifestyle that's in danger.