There has never been a force like humans with the technology that we have until recently, and with the amount of ecosystem destroying we're doing, starting with deforestation and all downhill from there (toxifying water, releasing ridiculous amounts of methane due to agriculture, and other dangerous chemicals through general vehicle/factory pollution - by the way, the earth itself releases a large a mount of these, namely in the form of volcanoes, but we're certainly not helping the issue, especially with all the trees we're killing to cope with it).
I'm not that worried about the Earth. I think the Earth will end up fine, pending an asteroid collision, it will have another 5 billion years or so before the sun dies. If the Earth goes into a 1-5 million year period of massive plant/animal extinction,
as it has before, it's not really that big of a deal It will end up flourishing again. Humans, however, are thus far the first animal to be cognizant enough to be able to foresee, prevent (in some cases), prepare and possibly survive one of these extinctions due to our intelligence. And the way we're treating the planet is just going to end up killing us even faster, even if it's inevitable anyways.