The threat of climate change isn't significant enough for him to liquidate his investments?
It wouldn't surprise me if the linked article doesn't mark the start of a shift in focus to address climate change as well. You may not be a fan of Bill Gates but when it comes to putting his money where his mouth is he has a pretty decent track record in recent years.
Edit to add: When you hold more assets then anyone else there's a limit to the rate that they can be liquidated without completely disrupting the global economy.