None of the atmospheric scientists are thinking about” how plants could influence rainfall, Swann said, though hints have appeared in the scientific literature for decades. And, she added, “it blows the ecology community’s mind … that the plants over here could actually influence the plants over there.”
Scientists reacted strongly. Early meteorologists, hoping to save their young field’s credibility, rejected the notion that forests influence weather. “Much of the discussion of it, unfortunately, has not been of a purely scientific character,” one wrote in 1888 in Science. Meteorology, and later climate science, became the study of air and water. Plants were relegated to passive-participant status.
Normally, we might assume that “the forests are there because it’s wet, rather than that it’s wet because there are forests,” said Douglas Sheil, an environmental scientist at the Norwegian University of Life Sciences campus outside Oslo. But maybe that’s all backwards. “Could [wet climates] be caused by the forests?” he asked.
Yet the question of how changes in forests could alter the global climate has barely been considered. “For decades, we’ve been looking to see: How well can we do in climate modeling without needing to evoke the influences of vegetation?” Williams said. “Vegetation has kind of been left on the back burner.”
Sheil is skeptical of the results of the Kooperman-led study. He thinks climate models do not represent plant biology and the physics of air movement and rainfall accurately enough to say anything meaningful about the real biological world. He notes, for example, that different climate models given the same input often make different predictions.
Addressing these concerns won’t happen overnight, however. Most models, unlike the CESM, can only be run at a modeling center by the handful of scientists who created them. Those people are busy running simulations for the next Intergovernmental Panel on Climate Change report, due out in 2022. None of the models being used fully accounts for plants’ influence on climate, Swann said.
Clouds cool the planet by reflecting incoming sunlight, but they also warm the planet because they are made of water vapor, a greenhouse gas. Models differ wildly on how much clouds will contribute to cooling and warming in the future, and thus whether a doubling of atmospheric carbon dioxide will be problematic but manageable, or catastrophic.
The developments in this new research area demonstrate that future climate scientists will need to master two fields that have, for more than a century, been largely separate, Fung said: atmospheric physics and biology.
“There are very few ‘multilingual’ scientists,” Fung said. “When Abby did her thing, it was the coming together of two disciplines.” She added, “That’s how progress is made.”
