That's a bold claim to say it's going to kill billions of people. What are you basing this on?

EDIT:

The World Health Organization estimated that between 2030 and 2050, climate change could cause approximately 250,000 additional deaths per year.

A study published in The Lancet projected that, under a high-emission scenario, climate change could cause an additional 1.7 to 3.2 million deaths per year by 2100