How do fossils show us the impact of climate change and environmental change?
By looking at a fossil you can tell what kind of environment it most likely was or lived in.
How many species are extinct due to climate change?
"One in six of world's species faces extinction due to climate change."
"Certainly paleontologists have found samples of an extremely small fraction only, of the earth's extinct species, and even for groups that are mostly readily preserved and found as fossils they can never expect to find more than a fraction."