Planting trees could be a "mind-blowing" solution to climate change

Pablo Tucker
July 6, 2019

Scientists say planting a trillion trees globally could be the single most effective way to fight climate change.

The Crowther Lab at ETH Zurich investigates nature-based solutions to climate change. Researchers estimate that even with existing cities and farmland, there's enough space for new trees to cover 9 million square kilometres around the globe or about the area of the United States.

After recently publishing the most negative "OMG we're stuffed" post about climate change ever, it is a pleasure to write that we really can cure this, with carbon capture and storage - in trees.

"This is by far - by thousands of times - the cheapest climate change solution" and the most effective, said study co-author Thomas Crowther, a climate change ecologist at the Swiss Federal Institute of Technology in Zurich. "Our study shows clearly that forest restoration is the best climate change solution available today".

Once these trees matured they could pull down around 200 gigatonnes of carbon dioxide, some two-thirds of extra carbon from human activities put into the atmosphere since the industrial revolution.

A female adult jaguar sits atop a tree at the Mamiraua Sustainable Development Reserve in Uarini, Amazonas state, Brazil. The greatest po-tential can be found in just six countries: Russian Federation (151 million hectares); the USA (103 million hectares); Canada (78.4 million hectares); Australia (58 million hectares); Brazil (49.7 million hectares); and China (40.2 million hectares).

Forests could be regrown on 1.7 billion-1.8 billion hectares of denuded areas that are no longer in use, adding 1.4 billion hectares if cropland and urban areas were included, it said.

There are also many opportunities that present themselves in a reforested and afforested world, including the transformation of the construction industry to wood (continuing to store the Carbon dioxide in buildings as well as trees) and forest farming, which promises "abundance, as well as the kind of resilience a changing climate demands". The study's lead author, Jean-Francois Bastin, estimated there's space for at least 1 trillion more trees, and potentially 1.5 trillion, AP reports, on top of the estimated 3 trillion trees now on the planet. That's about as much carbon pollution as humans have spewed in the past 25 years.

However, not everyone was as effusive about the new study.

The study also warns that some existing climate models are wrong in expecting climate change to increase global tree cover. It finds that there is likely to be an increase in the area of northern boreal forests in re-gions such as Siberia, but tree cover there averages only 30 to 40 percent. But a proposal that costs a tenth as much as carbon capture and geoengineering has to be given serious consideration. "I get uneasy when we start talking about managing billions of extra acres of land, with one goal in mind: to store carbon". "You can grow trees yourself, donate to forest restoration organizations or just invest your money responsibly in businesses which are taking action on climate change".

"Finally an authoritative assessment of how much land we can and should cover with trees without impinging on food production or living areas", she said in a statement.

"None of this works without emissions cuts". This new research demonstrates how much natural capacity our planet has to grow and sustain additional forest; now, the challenge is to understand how and where we can accelerate this implementation, whilst still feeding our growing global population.

The researchers used Google Earth to see what areas could support more trees, while leaving room for people and crops.

Researchers analyzed tree cover in protected forest areas largely unaffected by human activity across the Earth's ecosystems, from arctic tundra to equatorial rainforest, studying almost 80,000 high resolution satellite photographs.

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