He's already liquidating them pretty quickly to fund the vast amounts he's ploughing into eradicating polio and malaria, and projects to provide access to clean water, contraception and decent sanitation in the developing world.
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.