Billions: “I met Paul when I was in 7th grade, and it changed my life,” Bill Gates writes in this tribute to his Microsoft co-founder Paul Allen, who died Monday. Allen was among an initial group of the ultra-wealthy in 2010 who’d pledged at least half their fortunes to philanthropy—but when he died, he was still worth $20 billion, 48 percent more than when he first made the pledge. How the American financial system is structured can keep even the most giving of billionaires unimaginably wealthy.
Have scientific models of how the world is warming failed to properly consider the impact of trees and other greenery?
“For decades, we’ve been looking to see: How well can we do in climate modeling without needing to evoke the influences of vegetation?” said Park Williams, a bioclimatologist at Columbia University. “Vegetation has kind of been left on the back burner.”
Studies of individual leaves have shown that when plants are bathed in carbon dioxide, they don’t need to make as many stomata per leaf, and they close the ones they do make more of the time. These changes help forest plants conserve water to survive, but they reduce the water vapor available to fall as rain on the surrounding continent. Moreover, when plants transpire, they cool Earth’s surface and warm the air, just as the evaporation of sweat cools your body on a hot day. Leaf-level changes, scaled up across continents, could rob the atmosphere of moisture and warm the planet’s surface.