Planting trees is the best tool around for stopping global heating, suggests a new study, and Canada can host a lot more of them – enough to support a new forest a bit bigger than Alberta.
ETH Zurich ecologist Jean-François Bastin published a study in Science Thursday that is the first to calculate the amount of additional trees that could be planted to combat global heating without encroaching on crop or urban areas.
While scientists have long known that trees can trap carbon emissions in wood and soil, it’s been an open question as to whether or not the planet could support the number of trees needed to offset global heating, the study notes. The Intergovernmental Panel on Climate Change had predicted that about a billion hectares of trees would have to be planted to limit global heating to 1.5 C by 2030.
Bastin and his team fed databases on current global forest cover and climate and soil conditions into a computer model to see how much more additional forest the Earth could support.
“We all knew restoring forests could play a part in tackling climate change, but we had no scientific understanding of what impact this could make,” study co-author Thomas Crowther said in press release.
The team identified about 0.9 billion hectares of land not currently used by cities or farmers that could be reforested under current climate conditions. Canada alone could potentially reforest an area roughly 1.2 times the size of Alberta. (See www.crowtherlab.com/maps-2 for a map of the world's forest restoration potential.)
The team found that restoring all this forest would remove some 205 gigatonnes of carbon from the air – about two-thirds of humanity’s carbon emissions since the start of the industrial age.
“Our study shows clearly that forest restoration is the best climate change solution available today and it provides hard evidence to justify investment,” Crowther said.
“If we act now, this could cut carbon dioxide in the atmosphere by up to 25 per cent to levels last seen almost a century ago.”
Crowther said it was still vital to continue to protect today’s forests and phase out fossil fuels to prevent further global heating, as it would take decades for these new forests to mature.
“Although government action is essential to make the most of this opportunity, this is a climate solution we can all get involved in and make a tangible impact,” he noted, adding that individuals could help by planting trees and supporting forest restoration groups.
The study is available in this week’s edition of Science.