NASA most definitely studies climate change. Just Google NASA climate change or NASA Greenland ice melting and you can find plenty about NASA scientists studies of the topic.

As far as climate change my opinion is that yes there is warming, but personally I don't think there has been any proven link between that and mans behavior. Sure we may be adding to it to a slight degree, but likely there are many forces and variables that attribute variations to the climate over spans of time that are far beyond our control.