The world has 3.04 trillion trees, vastly more than researchers previously believed, but a study published last week in the journal Nature concludes that the earth’s tree cover has declined 46% since humanity “started the lengthy, but recently accelerating, process of deforestation,” the Washington Post reports.
“We can now say there are fewer trees than at any point in human civilization,” said post-doctoral researcher Thomas Crowther of the Yale School of Forestry and Environmental Studies, who served as lead author for a team of 38 researchers involved with the study.
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“Since the spread of human influence, we’ve reduced the number almost by half, which is an astronomical thing.”
Mooney points to the study’s implications for climate change. “Trees pull carbon dioxide out of the atmosphere as they grow, and cutting or burning them down releases that carbon again,” he writes. “That means deforestation is making global warming worse—and it also means that if we were living on an Earth with close to 6 trillion trees, rather than 3 trillion, climate change would be less severe.”
Crowther said the study was inspired in part by the Billion Tree Campaign, originally launched by the UN Environment Programme in 2006. “They want to generate forests on a global scale,” he told the Post. “But they had absolutely no baseline information about how many trees they needed to plant to do that.”