Well known physicist Freeman Dyson discusses his view on global warming in two videos here. In one, he notes that current federal funding is focused on climate models which have little value without accurate input data. He discusses, for example, the interaction between atmosphere and plant life and how important it is to the global warming issue and yet how little is known:
There is more carbon in vegetation on the Earth than there is in the atmosphere. So that the atmosphere is the tail and and the ground is the dog, in this case. Vegetation is controlling what is happening rather than the atmosphere. ...You can't understand the atmosphere by itself. The vegetation is absolutely essential. Well, what do we know about the vegetation? Not very much.