I'm not a scientist, but, I have noticed certain changes since I was a boy. Cardinals..there never was a cardinal in Maine until recently. The latest immigrant, Possums! Unheard of! Plus, real cold weather and deep snow..nothing like it used to be, and I am not stretching it here either. The polar ice caps only have to melt a little bit to drown low countries such as Bangledesh. Guess what..its happening right now and you would have to be blind to not see it.