A physicist friend asks if there is someone in climate science who has made progress significant enough to deserve a Nobel Prize. It’s an interesting question. Any such prize would be amazingly controversial, but let’s shelve that and ask: who are the best climate scientists, the ones who have made truly dramatic progress?
Arrhenius is no longer with us, so he’s out.
Azimuth 
I’d have to nominate Akio Arakawa:
http://www.aip.org/history/climate/arakawa.htm
Wikipedia still has no page on Akio Arakawa…
Here’s some more: EGU Vilhelm Bjerknes Medal 2010
I’d nominate Charles David Keeling. Also note that Paul Crutzen and Mario Molina, two scientists who have made major contributions to climate science, shared the 1995 chemistry Nobel – but for work on the ozone hole, not climate. I believe this is the only Nobel awarded for work in the earth/environmental sciences.
Crutzen and Molina shared the Nobel Prize for Chemistry in 1995 with Sherwood Rowland (who is the source of the memorable quote “What’s the use of having developed a science well enough to make predictions if, in the end, all we’re willing to do is stand around and wait for them to come true?”
Other notable giants in climate science are the late Stephen Schneider and Jim Hansen, though it’s more their whole body of work rather than one specific theme that is remarkable about their scientific achievements. Seems less picture perfect for a Nobel prize at first sight, cuz of the lack of a suitable elevator pitch.
I think this is why Keeling would have been the most likely climate scientist to qualify for a Nobel – his work on the global carbon cycle from atmospheric measurements was succinct, definitive, and iconic. In contrast to a figure like Hansen who, as you say, is notable more for a broad body of important work rather than a single definitive and transformative study. However it occurs to me now that Keeling has died and is therefor not eligible for the Nobel.
Thanks also for relating the Rowland quote.
Another worthwhile nominee would be Suki Manabe. He made a quantitative estimate of climate sensitivity in the 1960’s that is not much different from today’s best guess. He also postulated that relative humidity would remain constant as the Earth warmed—an insightful hunch that has been more or less validated by empirical studies and physical process modeling.
Ha, perhaps we can all pitch in $15 dollars and start the ‘Azimuth Prize’!
James Hansen. He moved more minds than most.