This planet will survive us, and has been through much much worse many times over. We may work to save our planet or we won't, and the Yellowstone Caldera will erupt again. Lake Michigan itself is a temporary puddle left after the last glacial sheet covered Michigan just 10,000 years ago. With or without us, it likely won't be here much longer on a geological timescale. Every age is the end of one and the beginning of another. That's not to say that these things don't matter. They do as much as anything else does. However, I think it's worth understanding that the value that we put on our natural environment only resides within us. There's a lot of good in this world, but it isn't expressed well on a global scale. If you want to feel better about how the natural environment fairs in the US, visit China or India.