"We" arent that powerful, the best we could do is exterminate our selves, but life would continue, and adapt.

If we dedicated ourselves to wiping out the biosphere, I'm sure we could. But the current nuclear arsenal wouldn't cut it.

At best we could destroy civilization, but probably not even humanity.

We sure are. We can blacken the sun, wipe away the ozone layer, irradiate and poison the earth, freeze the oceans, we can drill down to nearly the mantle, introduce plagues that can ravage continents and over time, we can fracture the earth's ecosystems so badly that a meteor strike will look like a pebble drop.

Every living thing on the planet will die as a result.