Forests alone will not be able to help us much longer

Against the climate crisis we cannot count on forests or imagine planting trees everywhere. As essential as they are to our survival on this planet, forests cannot be the “solution” to the problem of growing trees CO emissions₂ he was born in global warming which follows. According to a study led by Caspar Roebroek And Alexander Cescatti of the Joint Research Center of Ispra (Italy) and published on Scienceindeed, the Forests alone can do little: existing ones could only act as a buffer against current emissions for the next four years, even if we hypothetically stop exploiting them starting today. Preserving them obviously remains essential, but to reduce CO₂ and combating the climate crisis is necessary – and it must be reiterated, even if it may seem obvious – first of all to drastically and globally reduce emissions, and to do it immediately.

As we know, plants absorb CO₂ from the environment and transform it, through the process of chlorophyll photosynthesis (which also requires water and solar energy), into oxygen and glucose: the latter constitutes their source of nourishment. In this way, trees and forests in general act as real “warehouses of CO₂“, or, better said, carbon. But how much more can they accumulate? According to the authors of the research, the results of previously published studies tend to provide us with overestimated values, not taking into consideration some factors. To answer the question, the research group has therefore developed a model that is able to calculate the realistic “carbon carrying capacity” under conditions of natural equilibrium. That is, taking into consideration those factors that cause the natural loss of trees and plants and instead excluding anthropic factors.

According to their findings, the ability of currently existing forests to store CO₂ it would increase by 15% if we eliminated any human activity connected to them, from obtaining wood, to extinguishing fires of natural origin.

Several studies tell us that, from a global perspective, forests left completely intact and free from any anthropic activity (even from those that could apparently have positive impacts) are able to absorb a much greater quantity of CO₂. In any case, as we were saying, even in conditions of natural balance, the forests on our planet could at best compensate for the current emission rates for the next four years.

It is therefore natural to ask whether increasing its extension could be an option to consider. Unfortunately, the question is not that simple, as reported by one of the reports of the IPCC (Intergovernmental Panel on Climate Change). What is called in English “afforestation”, ie the increase of forest areas to the detriment of native grasslands or pastures, is in fact not without consequences. First, forest-free soil also has an impact on CO sequestration₂. Furthermore, replacing natural pastures with forests, especially if in semi-arid areas and especially with fast growing trees, can alter the local aquifer balance potentially causing local water crises. Last but not least, replacing natural pastures with forests can obviously have negative impacts on biodiversity and also on the availability of land for agricultural purposes.

We cannot therefore think that reversing the trend towards deforestation, however necessary, can be an alternative to reducing emissions. Climate mitigation programs, the authors conclude, should at most consider the carbon storage capacity of existing forests as a way to offset those emissions that realistically cannot be completely zeroed in the future.