Jeff Bezos is the richest person on earth. Up to now he has not been in the running for most generous

Of the top five richest humans, Bezos is the only one who hasn't signed the Giving Pledge to give away at least half his net worth. His paltry $900,000 donation to aid forest fire-ravaged Australia drew sneers. Kylie Jenner pledged more. Amazon employees have protested the company's sluggish response to climate change (Bezos threatened to fire them). Meanwhile, the top headlines about the Amazon founder recently concerned his decision to buy a $165M Beverly Hills estate

But Bezos may be turning things around. On Instagram yesterday he announced that he's donating $10 billion -- about 7.7 percent of his net worth -- to combat climate change. The funds will go to scientists, activists, and NGOs fighting the climate crisis. He intends to start issuing grants this summer. The pledge is entirely separate from his Bezos Day One Fund, aimed at tackling homelessness and helping kids from low-income communities. 

"Climate change is the biggest threat to our planet. I want to work alongside others both to amplify known ways and to explore new ways of fighting the devastating impact of climate change on this planet we all share," Bezos wrote. Here's the complete post: 

The effort may be the beginning of a turnaround in Bezos's reputation for being tightfisted with his billions, but at least one group isn't ready to cheer yet.

Amazon Employees for Climate Justice tweeted out a response applauding Bezos for his personal efforts, but complaining that Amazon, despite recent pledges to go carbon neutral by 2040, continues to fund climate-change denying groups and rely on fossil fuel-burning delivery vehicles, 

"One hand cannot give what the other is taking away," the statement read. 

What's your view: Has Bezos done enough to put his vast wealth to use for the greater good?