Could planting trees make enough difference to impact increased CO2 levels on a global level? The idea seems simple enough. Since trees and plants take in carbon dioxide for photosynthesis, theoretically planting enough trees should reduce CO2.
The terrestrial biosphere - which includes plants and trees - does have an impact on global CO2 levels. Combined with oceans, the terrestrial biosphere removes about 45% of the CO2 emitted by human activities each year. According to research done at UC Berkley, there is evidence that as global CO2 levels have increased, the terrestrial biosphere is responding by taking up more CO2 and reducing the rate of growth of global CO2.
This makes sense. Here at CO2Meter, our clients report to us that in controlled conditions like indoor greenhouses, doubling or tripling the CO2 level acts as fertilizer, increasing the growth of plants.
Could enough trees be planted to impact CO2?
Probably not. A tree can absorb as much as 48 pounds of carbon dioxide per year and can sequester 1 ton of carbon dioxide by the time it reaches 40 years old.
One ton of CO2 is a lot. However, on average human activity puts about 40 billion tons of CO2 into the air each year. This means we’d theoretically have to plant 40 billion trees every year, then wait for decades to see any positive effect. By the time 40 years rolled around, we’d run out of land to plant any more trees.
In July of 2016, 800,000 volunteers in India planted 50 million tree saplings in an effort to re-green the country. While there are many good reasons to combat deforestation, this project would have to be replicated 800 times a year globally to cancel out the CO2 created by humans.
So the answer seems to be that planting trees, while a good idea, would not cancel the effects of human production of CO2. Instead, we can either take steps to reduce CO2 emissions now, or wait and see what happens. Only good science and good data will give us the best answer.