According to a study published in 2020, protecting trees and planting new ones could go a long way in reducing carbon dioxide emissions by up to 6 megatons per year between 2025 and 2055 . Although, as the authors estimated, this strategy would have a cost: up to $ 324 billion a year.
As the authors of that study maintained, “forests are essential to stabilize our climate, but the costs of reduction in space, time and different actors remain uncertain.
Taking different scenarios into account, the scientists at that time evaluated the potential and cost of planting, managing and protecting forests against climate change, suggesting that trees could be extremely useful in reducing carbon dioxide emissions. between 0.6 and 6 billion tons per year by 2055 .
But not all approaches would be the same. And they discovered that protecting existing forests would be more effective and less expensive than planting new ones, so a reduction in deforestation would allow an average annual decrease of 0.3 to 1.8 gigatons of CO2 per year. In comparison, reforestation would decrease between 0.1 and 2.6 gigatons per year during the same time period.
On the other hand, we already know that plants feed in part on the carbon dioxide that we find present in our atmosphere , which is why scientists consider that forests are, in fact, important carbon sinks, capable of storing CO2 for longer. or less time.
Thus, together with soils, forests are capable of retaining around a third of our carbon emissions. And many see it, even, as a pillar in the fight against anthropogenic global warming .
In this context, researchers at the Lawrence Berkeley National Laboratory, in the United States, asked the following question: do plants capture more carbon now than in the past? And, if so, to what extent?
They concluded that, indeed, plants now tend to sequester more carbon than in the past . While, in addition, they were able to record an increase in photosynthesis – which consumes CO2 – of 12% between 1982 and 2020.
In the amount of additional CO2 removed from our atmosphere, this would equal 12 billion tons .
Although it is true that a large part of the carbon removed from the atmosphere by photosynthesis is then released back into the atmosphere by plant respiration, the researchers claim that there is a direct link between increased photosynthesis and increased global storage of carbon .
To reach this conclusion, the scientists relied on data from more than 500 micrometeorological towers scattered around the world, as well as satellite images. In turn, they examined nearly three decades of carbon sink estimation, which they then compared with predictions from satellite images and models of carbon exchanges between the atmosphere and the land.
This is how they concluded, with some confidence, that photosynthesis has increased by 12% since the early 1980s .
Despite this, the researchers also point out that this increase, significant as it may be, would be far from compensating for the amount of CO2 we release into the atmosphere . In fact, by 2021, experts expect emissions of 39 billion tons, well above the mentioned figure.
