EvilGoalie 21
GOLD
I would not be surprised to get into the delorean, jet back 120,000 years, apply the same attention, and see a really radical swing at the top of that matterhorn.
We could also dial in 500,000 years back on the flux capacitor, and see a more homogenous period of climate fluctuation, sans human "forcings".
You could save some gas, only go back ~75,000 years, and catch Toba. That gave the temp anomaly graph a pretty good short term twitch.