Divestment is one of the fastest-growing movements in the fight against climate change. It’s only getting started. Harvard University sits on a gargantuan and growing pile of money. At $39.2 billion, its endowment is the largest academic fund in the world. And it grew 10 percent last year. In 2018, it paid out $1.8 billion in dividends, more than one-third of the university’s operating budget. But a campus rally last month showed that an increasing number of students, faculty, and alumni believe that Harvard’s endowment is gambling with the future of the planet.