New research ensures that the world has an area equivalent to the surface of the United States to plant trees, and that this action could give a positive turn in the dramatic fight against climate change.
The study carried out by scientists from the ETH-Zurich University in Switzerland shows that the space described for planting new trees is much larger than previously thought, and would reduce carbon dioxide (CO2) in the atmosphere by 25%.
The authors of the study are very optimistic, assuring that it is the most effective solution for climate change that the world has at the moment.
Other researchers distrust the results of the investigation, they are “too good to be true“.
The ability of trees to absorb carbon dioxide is known, which is why this strategy would be a valuable weapon in the fight against rising temperatures.
The Intergovernmental Panel on Climate Change (IPCC) said that if the world wanted to limit the rise to 1.5 ° C by 2050, an additional million hectares of trees would be needed.
This new report tries to show not only how many trees can be grown, but also where they can be planted and the impact they would have on carbon emissions.
The study also indicates that this reforestation would offer the human being a time of about 20 years so that the new technologies that would allow to get rid of fossil fuels would be available.
"The best solution"
Scientists at the Swiss University ETH-Zurich used a method called photointerpretation to examine a global data set of observations covering 78,000 forests.
Using Google Earth mapping software, they were able to develop a predictive model to map the global potential for tree planting.
The researchers found that excluding existing trees, farmland, and urban areas, the world could support an additional 900 million hectares of tree cover.
Once these trees mature, they could knock down around 200 gigatons of carbon dioxide - about two-thirds of the additional carbon from human activities introduced into the atmosphere since the industrial revolution.
This is a quarter of the total amount of CO2 in the air.
“Our study clearly shows that forest restoration is the best solution to climate change available today and provides strong evidence to justify the investment"Says Professor Tom Crowther, lead author of the study.
“If we act now, this could reduce carbon dioxide in the atmosphere by as much as 25%, to levels last seen nearly a century ago“.
An "authoritative evaluation"
The researchers identified six countries where the majority of forest restoration could occur: Russia (151 million hectares), the United States (103 million), Canada (78), Australia (58), Brazil (50) and China (40) .
According to the study, starting as early as possible is essential because as the world continues to warm, the potential area for planting trees in the tropics will shrink.
“It will take decades for new forests to mature and reach this potentialCrowther comments.
“It is vitally important that we protect the forests that exist today, seek other solutions to the climate problem, and continue to eliminate fossil fuels from our economies.“.
The new study was welcomed by Christiana Figueres, a former UN climate chief, who was a pivotal figure in achieving the 2015 Paris climate accord.
“Finally, an authoritative assessment of how much land we can and should cover with trees without affecting food production or housing areasFigueres said in a statement.
“An extremely important model for governments and the private sector“.
What do the critics think?
However, not everyone was as effusive about the new study.
Several researchers expressed reservations, saying that they did not agree with the idea that planting trees is the best solution to climate change at the present time.
“Tree restoration may be 'among the most effective strategies', butis far from being 'the best solution available to climate change', And it is a long way from being able to reduce fossil fuel emissions to zero‘” Said Professor Myles Allen, University of Oxford, UK.
Others criticized estimates of the carbon that could be stored if these trees were planted.
“The estimate that the restoration of 900 million hectares can store 205 billion additional tons of carbon is too high and is not supported by previous studies or climate models"Said Professor Simon Lewis, University College London.
“Planting trees to absorb two-thirds of the entire anthropogenic carbon load to date seems too good to be true. Probably because it is"Said Professor Martin Lukac, University of Reading.
Reference scientific article:
The global tree restoration potential Jean-Francois Bastin et al.Science05 Jul 2019: Vol. 365, Issue 6448, pp. 76-79 DOI: 10.1126 / science.aax0848
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