Duncan McLaren: Planting almost a billion hectares of trees worldwide is the “biggest and cheapest tool” for tackling climate change, according to a new study. The researchers claimed that reforestation could remove 205 gigatonnes of carbon from the atmosphere – equivalent to about 20 years’ worth of the world’s current emissions. This has criticised as an exaggeration. It could actually be dangerous. While the paper itself included no costings, the researchers suggested a best-case estimate of just US$300 billion to plant trees on 0.9 billion hectares. That’s just 40 US cents per tonne of carbon dioxide (CO₂) removed. More detailed studies on the costs of carbon removal through reforestation put the figure closer to US$20-50 per tonne – and even this may be optimistic at such large scales. Our research suggests that the promises implied in such studies could actually set back meaningful action on climate change. This is because of what we call “mitigation deterrence” – promises of cheap and easy CO₂ removal in future make it less likely that time and money will be invested in reducing emissions now.
The Conversation 12th July 2019 read more »