Larry "Brilliant" suggests that "There's an odorless, colorless, tasteless, invisible gas that's going to destroy the world 20 years from now"?

Larry Brilliant on Climate Change as the Greatest Risk We Face - WSJ.com

Climate change is the greatest risk we face. It's the great exacerbater. It exacerbates the risk of pandemics. It exacerbates the risks of water. It exacerbates the risk of conflict.
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I was the CEO of two public companies. When I'm looking at quarterly profits, I start working on the next 90 days before this 90 days is over. How can I look up, in all honesty, and say, "There's an odorless, colorless, tasteless, invisible gas that's going to destroy the world 20 years from now"?

No offense, Larry, but are you insane?   Why, specifically, do you imagine that risks of pandemics/water problems/conflict/etc/etc would rise if the Earth warmed by, say, 1 degree F. from here?  How, specifically, do you know that those risks wouldn't drop or maybe fail to change in any statistically significant way?