It is estimated that there are at least seven times more trees than previously thought. And there is still room to reforest and absorb all the emissions produced each year by human activities.
The planet is greener than previously thought. And that can only be good news. So says researcher Tom Crowther of the ETH Zurich, who at a conference held in Washington presented the latest findings from the Crowther Lab: there are 3,040 billion trees on the planet, seven times more than previously estimated. This means that the planet has a greater capacity to absorb CO2 emissions. Moreover, according to the scientist, there would be room for another 1.2 trillion new trees globally, which would be capable of absorbing more carbon than is emitted by human activities each year.
Read also: The slow abandonment of Italy's forests
This result was achieved through the processing of thousands upon thousands of data points from around the world. In their research, the scientists at the Crowther Lab used the largest dataset from forest inventories, the Global forest biodiversity initiative, measured by researchers in more than 1.2 million locations worldwide, combining these with data provided by satellites. The laboratory also used a database that studies above- and below-ground soil ecology, describing how billions of subterranean species are able to determine soil fertility, atmospheric composition and therefore also influence the climate.
"With multispectral imaging and remote-sensing radar we are able to provide data down to a resolution of 3.7 metres: enough to distinguish individual trees," Crowther writes in a post hosted on the research institution's website. "Our laboratory is improving climate predictions with data containing more than 30 million measurements of individual trees and 120,000 measurements of soil communities from around the world, collected through our global network made up of thousands of ecologists."
This has also made it possible to assess the role of soil in climate change. Soil constitutes a natural carbon reservoir, the second most important after the oceans. Depending on the region, climate change can cause greater carbon accumulation in plants and soil due to vegetation growth, or greater release of carbon into the atmosphere. And this is precisely the point: the working group discovered that the warming of certain ecosystems, such as Arctic and sub-Arctic regions, is causing the release of carbon. A process that could lead to the emission of 55 gigatonnes of carbon stored in the soil — roughly the equivalent of all annual CO2 emissions from the United States. Emissions that would cause climate change to accelerate by 17 per cent.
All the more reason for scientists to assert that restoring vegetation, planting new trees and protecting soils are by far the best weapon in the fight against climate change.