Planting a billion trees to mitigate climate change: a simplistic solution to a complex issue

In July 2019, a paper published in Science claimed that global tree planting could capture 205 gigatons of carbon, or one-third of the carbon dioxide emitted since the industrial revolution. These numbers were so large that headlines around the world declared tree planting to be the best solution to climate change.

In a technical comment published October 18 in Science and led by Joe Veldman (Texas A&M University), we demonstrate that this paper largely overstated the potential for tree planting to mitigate climate change, and that planting trees in the wrong places can destroy ecosystems, increase wildfire intensity, and exacerbate global warming.

Two other independent technical comments were also published the same day (here and here), urging caution and pointing out flaws in the original paper:

  • Maximum carbon storage per forest area was overestimated
  • Soil organic carbon in ecosystem without trees or with few trees was assumed to be 0.
  • Feedbacks with albedo and [CO2] were ignored in future projections
  • And ecosystems were targeted for restoration while having few or no trees naturally (grasslands, savannas and peatlands).

Here is there rebuttal.

It has attracted some press attention here in Quebec and in France: