Climate change: Trees ‘most effective solution’ for warming
Researchers say an area the size of the US is available for planting trees around the world, and this could have a dramatic impact on climate change.
Planting billions of trees across the world is by far the biggest and cheapest way to tackle the climate crisis, according to scientists, who have made the first calculation of how many more trees could be planted without encroaching on crop land or urban areas.
The study shows that the space available for trees is far greater than previously thought, and would reduce CO2 in the atmosphere by 25%. The authors say that this is the most effective climate change solution available to the world right now.
The new trees would remove around 200 gigatonnes of carbon, or two thirds of what humans have pumped into the atmosphere since the industrial revolution. The ability of trees to soak up carbon dioxide has long made them a valuable weapon in the fight against rising temperatures.
However, the researchers emphasized that tree planting was not a replacement for reducing greenhouse gas emissions or phasing out the use of fossil fuels.
The study, published in the journal Science, determines the potential for tree planting but does not address how a global tree planting programme would be paid for and delivered. The research is based on the measurement of the tree cover by hundreds of people in 80,000 high-resolution satellite images from Google Earth. Artificial intelligence computing then combined this data with 10 key soil, topography and climate factors to create a global map of where trees could grow.
This showed that about two-thirds of all land – 8.7bn ha – could support forest, and that 5.5bn ha already has trees. Of the 3.2bn ha of treeless land, 1.5bn ha is used for growing food, leaving 1.7bn of potential forest land in areas that were previously degraded or sparsely vegetated.
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. This is a quarter of the overall amount of CO2 in the air. Even if tree planting began today, it would take 50 to 100 years for the new trees to soak up those 200 gigatonnes of carbon.
The researchers identify six countries where the bulk of the forest restoration could occur: Russia (151m hectares), US (103m), Canada (78m), Australia (58m), Brazil (50m) and China (40m).
