Wally Broecker is known as the "grandfather of climate science" for good reason. He was researching, writing about and speaking out about climate change as far back as the 1960s, when few others were taking note.

Broecker, a geoscientist who teaches in the Department of Earth and Environmental Sciences at Columbia University, recently visited Tucson to lecture.

He said in an AZ Illustrated Nature interview that it's too hard to predict what the ultimate impact of climate change will be in a place such as Arizona, but he said it appears that the weather will become more extreme, with even drier conditions.