Restoring and Protecting Forests: A Promising Solution for Carbon Removal

A recent study published in the journal Nature reveals that the restoration and protection of the world's forests could have a significant impact on mitigating climate change. According to the study, approximately 226 billion tons of carbon could be removed from the atmosphere if forests are properly managed. This amount is equivalent to the emissions produced by burning fossil fuels at current rates for about 20 years. While some experts believe this research provides a more reliable estimate of forests' carbon capture potential compared to a controversial previous study, skeptics remain uncertain about the feasibility of achieving this figure.

Wayne Walker, the chief scientific officer at the Woodville Climate Research Center in the United States, who was not involved in the study, emphasizes the crucial role that forests play in combating the climate crisis. While uncertainties remain regarding the exact amount of carbon that forests can sequester, the evidence is compelling enough to justify taking action to plant, restore, and protect forests.

Deforestation has led to the depletion of a significant portion, even up to half, of the world's forests. Each year, greenhouse gas emissions resulting from deforestation contribute to 15% of the total human greenhouse gas emissions. Therefore, scientists have been keen to understand the potential carbon absorption capacity of trees if forests were allowed to regenerate.

In 2019, ecologist Thomas Crowther and his team from the Swiss Federal Institute of Technology in Zurich published a study in the journal Science, estimating that the restoration of 900 million hectares of land with forests could absorb 205 billion tons of carbon. However, some scientists question this figure, suggesting that it overestimates the carbon capture potential by assuming that each hectare of forest can store 227 tonnes of carbon.

Simon Lewis, a global change scientist at University College London and the University of Leeds in the UK, finds the estimate of 227 tonnes per hectare to be unrealistic. Additionally, concerns have been raised that the study may encourage initiatives like large-scale forest plantations, which are less beneficial to biodiversity and carbon capture compared to natural and diverse forests.

Crowther's team utilized satellite data to estimate the current carbon storage capacity of forests and employed modeling techniques to project the potential carbon storage if reforestation efforts were implemented. In the new study, they incorporated ground-based data, which were extrapolated globally using machine learning models, alongside satellite data. The two estimates of global forest carbon differ by approximately 12%.

Furthermore, Crowther and his colleagues calculated the amount of carbon that could be stored if existing forests were allowed to reach old-growth status. Their estimate includes not only carbon stored in trees but also carbon present in dead wood, above-ground leaves, roots, and soil. The findings indicate that if existing forests are protected and preserved, they could eventually sequester 138 billion tons of carbon.

Crowther emphasizes the exciting potential for large-scale carbon capture through the protection of existing ecosystems. The study also reveals that restoring the tree cover to its previous extent would result in an additional absorption of 88 billion tons of carbon. Although this number is significant, it is lower than the team's previous estimate of 205 billion tons in 2019.