Two numbers may frame the future of the world’s climate: 51 billion and zero. Microsoft co-founder and philanthropist Bill Gates stressed both figures during an online Harvard Science Book Talk.
Fifty-one billion tons of greenhouse gases are released into the atmosphere each year. Zero is the number the planet needs to reach by the year 2050 to avoid worldwide climate catastrophe, Gates told viewers on Monday night.
“There are points at which when the corals die off, they never come back,” Gates said. “This is acidifying the ocean, and all the aqua ecosystems die off as that acid level goes up. As forests dry out, they are subject to both fires and infestations that kill all the trees, so you get a lot less trees. As the sea level goes up, the beaches go away.”
Near the Equator, that means rising temperatures would cause more extreme heat events where people eventually can’t go outside and can’t farm. That would create millions of climate refugees, Gates said.
Without changes in global practices, “It’s going to be essentially unlivable at the Equator by the end of the century… [leading to] the instability of hundreds of millions of people trying to get out of those regions where a lot of the world’s population is, and particularly the poorest in the world,” he said.
Gates offered the warning as part of remarks sponsored by the Harvard Division of Science, the Cabot Science Library, and the Harvard Book Store. At the moderated event, he outlined some of the arguments in his new book, “How to Avoid a Climate Disaster: The Solutions We Have and the Breakthroughs We Need.”
Gates, the world’s third-richest person, has spent more than a decade investigating the causes and effects of climate change, working with experts in a range of fields and investing in innovations to address the concern in his new book, he shares what he has learned in an accessible way. He proposes immediate actions over the next decade and beyond to build or scale the tools and solutions needed to combat climate change and eliminate greenhouse gas emissions.
The talk was moderated by Savannah Guthrie, co-anchor of “Today” and NBC News chief legal correspondent.
At the start of the talk, she asked Gates to stress why the world needs to reach net-zero greenhouse gas emissions by 2050.
“The reason the goal should be zero is that when you put CO2 [carbon dioxide] up into the atmosphere, it stays there for thousands of years, so it’s the sum of all the CO2 you’ve put up for all the time since the Industrial Age. That determines how much we push the temperature up,” Gates said. “Pushing the temperature up is what creates those hurricanes, dries things out, actually creates floods. Surprisingly, it allows cold air from up in the north to come down into the United States, like we’ve seen last week all the way down to Texas.”
The CO2 accumulates like water in a bathtub that’s already almost full, he said. When it hits a certain level, it overflows and, in the case of climate, it tips.
