How Many Trees Would We Need to Plant to Slow Climate Change?

United Nations. Intergovernmental Panel on Climate Change or IPCC stated that rapid, quote, far reaching and unprecedented changes in all aspects of society would be needed in order to drop carbon dioxide levels by and prevent catastrophic global warming. Scientists have indeed proposed drastic measures, just not the way that

you might think. In the same i p c C report, the u N suggested that adding two point five billion acres that's one billion hectares of forest to the world could help limit global warming in future decades to just two and seven degrees fahrenheit that's one point five degrees celsius, which would stave off some of the worst effects of climate change. And now the U N might just have

the data to back up their proposal. In another study unveiled in July of twenty nineteen and the publication Science, a group of researchers associated with the Crowther Lab in Switzerland found that global tree restoration to the tune of nine hundred million acres that's point nine billion hectares of canopy cover, an area that's approximately the size of the United States is quote our most effective climate change solution to date. That would require upwards of half a trillion trees.

These trees would store two hundred and five billion tons of carbon, or roughly two thirds of the carbon that's been omitted by we humans since the Industrial Revolution. Some news reports said that this much forest restoration is the equivalent of roughly one trillion trees, but that statistick is from an estimate in a report from but we spoke with the current studies lead author Jean Frascois Bastin via email.

He said the idea was to estimate what tree cover could be expected when you removed the human factor, i e. What specific types of forest would naturally occur in the absence of other development and where. The team used the form of artificial intelligence known as machine learning to build quote a model to link tree cover with climate, soil and topography based on seventy eight thousand observations of tree

cover in protected areas. The researchers then projected the data further to estimate the potential total tree cover of the whole planet if human civilization didn't exist. But of course humans do exist, so the team then excluded land currently being used for urban settlements, crop lands, and existing forests, which yielded the total amount of land available for restoration. The study offers a map showing how much tree coverage different parts of the globe might support, the top three

areas being Russia, Canada, and the United States. The studies timing a lines of current global efforts around ecological rest ration. A one example is the Trillion Trees Vision, which seeks to restore one trillion trees by fifty Another is the Bone Challenge, which is a partnership between the Government of Germany and the u n's International Union for Conservation of Nature that aims to restore three seventy one million acres of deep forested land by which is about of the

current studies recommendation. You might be thinking, well, that sounds pretty easy. Let's all roll up our sleeves and save the planet by planting one tree at a time, right, But some experts say the situation is actually a little more complicated than that rosy picture, especially if most nations don't chip into help. Although by fifty eight nations had banded together to commit an acreage that would exceed the BONB Challenge goal, most of the restoration work to date

has been done by only a few countries. We also spoke with Jim Hallett, chair of the Board of Directors for the Society of Ecological Restoration. He cited major challenges to implementing restoration on such a global scale, quote including financing, governance, land tenure and ownership, and capacity to do the work. There's ample evidence that in some contexts, if the benefits of restoration are not equally shared, the project will fail.

So incentive programs have to be carefully developed, and restorational loan will likely not be enough. It takes time, after all to implement such a big restoration projects, and also for these trees to store carbon, and how it stresses that we have to not just restore previously forested lands, but preserve what we've currently got. Other scientists question not only the practicality of the studies claims, but also the

studies very methodology. But we spoke with Ica Liling, climate change researcher and professor of horticultural sciences at the University of Bonne. He pointed out that some of the areas marked for restoration couldn't support more trees than they already do. Some of them are in permafrost regions for example. Also quote the methodology implicitly, probably not on purpose, implies that carbon stock is portional to canopy cover i e. Ecosystems

without trees contain no carbon. This is clearly false and strongly inflates the global estimate of restoration. Young Barner, Leedling's colleague and a professor for economics of sustainable land use at the University of Bonne, is similarly skeptical. Barner says that some of the areas being proposed for restoration under the current study are already in use for other purposes.

Barner considers the study to be a quote interesting academic exercise, but as a climate change mitigation strategy proposal, and it is being advertised as such, it sends a misleading signal to the international climate policy debate, but don't fret. Both Bustine and Hallett emphasize that the u N has declared thirty the Decade on Ecosystem restoration, which could spur nations to act quickly, and some countries are already tackling the

initiative head on. And according to Hallett, forest restoration boasts far more perks than just impacting climate change, including maintaining or even increasing bio diversity and preserving the ecosystem that we humans rely upon for our food and water. But even the studies authors acknowledge that it's going to take a lot of goodwill to make this grand vision of reality.

Bastine said, what we need is a universal action. International agencies and geo's governments all citizens anyone can be involved. Local communities and small organizations may be especially effective. While they do not have the same reach as national agencies, they have the benefit of knowing what works best in their own backyards. Today's episode was written by Terry our Lagata and produced by Tyler Clang. The brain Stuff is

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