In 2019, scientists calculated that the world could offset a lot of our carbon dioxide pollution by planting over 1.2 trillion trees, without encroaching on farmland or urban areas. They found that there are approximately 1.7 billion hectares of land that could be used to grow trees – an area bigger than the US and China combined. It would remove at least 100 years worth of CO2 emissions out of the air.1
The report raised important questions. How does tree planting help the planet? How much carbon dioxide does planting a tree offset?
How much CO2 does a tree absorb?
Trees reduce carbon dioxide in the air by absorbing it and using it to build their stems and leaves. The amount of carbon a tree absorbs depends on its species and its level of maturity. Older trees generally absorb more carbon than younger ones. Studies show that a typical hardwood tree can absorb up to 48 pounds (22 kilograms) of CO2 per year. A younger sapling absorbs much less than that.2
To prevent climate change, we need to drastically reduce the number of greenhouse gases released into the atmosphere.3 We also need to reduce carbon dioxide levels already in the air, and trees are the most efficient way to do this. But, they are not necessarily the silver bullet.
Is carbon offset tree planting the solution to climate change?
Trees are not a miracle cure for climate change either. Humans generate over 36 billion tons of carbon every year4. We would have to plant 40 billion trees every year just to absorb those emissions – after letting them mature.5
For example, in 2019, the government of Ethiopia claimed that it planted 350 million trees in 12 hours.6 Canada’s Justin Trudeau also promised in September 2019 to plant two billion trees in ten years.7 Even Trump vowed to plant one trillion trees.8
Although they do wonders for our environment and protect us from climate change, we cannot rely solely on planting trees to reduce carbon emissions. We have to act to reduce emissions at source by decarbonizing energy, transport, and agriculture too. Trees are the best and cheapest tool we have to protect our planet’s health. But they cannot undo the damage we have already caused alone.
- Carrington, D. (2019). Tree planting “has mind-blowing potential” to tackle climate crisis. [online] the Guardian. Available at: https://www.theguardian.com/environment/2019/jul/04/planting-billions-trees-best-tackle-climate-crisis-scientists-canopy-emissions.
- European Environment Agency. (n.d.). Trees help tackle climate change. [online] Available at: https://www.eea.europa.eu/articles/forests-health-and-climate-change/key-facts/trees-help-tackle-climate-change.
- Trust, W. (n.d.). How Trees Fight Climate Change. [online] Woodland Trust. Available at: https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/british-trees/how-trees-fight-climate-change/.
- Ritchie, H. and Roser, M. (2017). CO2 emissions. [online] Our World in Data. Available at: https://ourworldindata.org/co2-emissions.
- CO2 Meter. (2018). Could Global CO2 Levels be Reduced by Planting Trees? [online] Available at: https://www.co2meter.com/blogs/news/could-global-co2-levels-be-reduced-by-planting-trees.
- CNN, S.P. and H.R. (n.d.). Ethiopia plants more than 350 million trees in 12 hours. [online] CNN. Available at: https://edition.cnn.com/2019/07/29/africa/ethiopia-plants-350-million-trees-intl-hnk/index.html.
- Twitter. (n.d.). https://twitter.com/justintrudeau/status/1177613585381543936. [online] Available at: https://twitter.com/JustinTrudeau/status/1177613585381543936?s=20.
- Friedman, L. (2020). A Trillion Trees: How One Idea Triumphed Over Trump’s Climate Denialism. The New York Times. [online] 12 Feb. Available at: https://www.nytimes.com/2020/02/12/climate/trump-trees-climate-change.html.