A new study has found that there are about 3 trillion trees on Earth currently – a figure much higher than what scientists had previously estimated, but significantly lower than what it was in the past. Published in Nature, the study was led by Thomas Crowther, an ecologist at the Netherlands Institute of Ecology who did the research at Yale University.
THE LOSS IN TREES IS MAN-MADE
“The scale of human impact is astonishing,” Crowther said in a Nature news release. “Obviously we expected humans would have a prominent role, but I didn’t expect that it would come out as the as the strongest control on tree density.”
With his co-researchers, Crowther found 5.6 trillion trees existed prior to the existence of humans. And since 46% of trees have disappeared since their arrival, humans are unsurprisingly viewed as the source of the problem by the scientist.
“The negative relationships between tree density and anthropogenic land use exemplify how humans contend directly with natural forest ecosystems for space,” the study says. In other words: we made this mess.
WHY THE RESEARCH WAS DONE
According to the Associated Press, Crowther conducted the study after being asked by a United Nations-affiliated youth organization if planting a billion trees (which store carbon-dioxide, positively impacting the atmosphere) would be an effective action against climate change. He couldn’t say.
To figure it out, Crowther needed to figure out the amount of trees on Earth, which was previously thought to be just 400 billion. And though the new figure is trillions more than expected, the scientist warned against thinking that a higher number had any positive implications for climate change and deforestation: “We’re not saying, ‘Oh, everything’s fine’,” the scientist said.
People destroy 10 billion trees annually. Though other factors causing the decline throughout history may include pest outbreaks and wildfires, humans have basically been the central destroyer of trees. “Humans are diminishing that huge population on such a global scale,” the researcher said.
WHAT THE STUDY MEANS
Crowther’s study led him to believe that planting a billion trees wouldn’t by itself be a powerful action against climate change. Plant-for-the-Planet, the group that asked Crowther about their tree-planting goal, has since increased their objective to 18 billion.
HOW THE STUDY WAS DONE
The researchers used computer models, information from 429,775 measurements on the ground as well as satellite observations to make the models.
