Global warming, Martian style

We earthlings are not alone in undergoing climatic change according to NASA scientists as reported in a BBC article. The polar caps of frozen carbon dioxide have shrunk for the third summer in a row. Whether or not there is a link between evidence of climatic change on Earth & Mars, it goes some way in demonstrating that it is not necessary to have mankind (or martian-kind) as the prime cause (albeit indirectly) of "global warming".
That the global climate is changing is evident, but the exact sensitivity of this change to human industrial endeavours and the resulting pollution seems to be much less clear.