I mean not really once costal areas flood and the locations best for growing food change we will see massive issues with humanity surviving, the rest of the ecosystem would adapt, migrate and evolve to survive. Hell even chernobyl basically shows us even if we went the full nuclear option wildlife would bounce back better than before with just maybe shortened life expectancies. We are a lot more prone to die from changes than the wildlife on this planet is.
I think you're underestimating our ability to save our own asses through technology.
Even if all the soil for growing food goes to crap, we can just engineer food crops that can grow in that soil. Hell, NASA has a research project exploring how to grow crops in moon (Or maybe it was martian) soil. Humans are one of the most adaptable species, because if natural processes are too slow we can just augment it through our technological prowess.
Even if all the soil for growing food goes to crap, we can just engineer food crops that can grow in that soil.
It's not about soil going to crap its about the climate surrounding those areas changing. Moon and Mars experiments are about indoor climate controlled greenhouses which sure can be done anywhere but not at the scale needed for our current civilizations or to replace the agriculture infrastructure at scale we have now.
Short term, yes, no question. But long term (a million years and beyond) we look at different challenges life on earth will face.
It's a fact that it won't simply continue existing indefinitely. And definitely not in the diversity we know now. It's not likely for rabbits or another species to suddenly rise up to the task of inventing space travel. That would need way more time than what it takes for earth to be hit by an asteroid big enough so that life won't bounce back. The same goes for other types of mass extinction. Only humans have at least a slight chance to make life endure beyond earth.
I mean realistically even then we don't know for sure, it took humans and our ancestors a couple hundred thousand years to develop to to where we are at now. It's not to say any other of our closest relatives could end up on a similar path without us in the picture in a much more tropical climate as they are used too. The question is will the earth stabilize itself when we get to that point or will we take it out of balance so severely that it goes into run away warming like Venus ending all life.
Why shouldn't we care, though? Personally, I see no reason why we should not try to preserve life, especially when perhaps it's the only example of life there is.
Rationally, since we don't know whether there is a reason for anything, the only thing we can do is to insure that someone in the future will be able to find it. That chance is 0 if life stops existing altogether.