Reforestation could sequester 22 times more carbon dioxide than is annually emitted into the atmosphere in the world, according to the results of a scientific study, according to which trees, along with the reduction of fossil fuels, are a key tool in the fight against climate change.

As part of the study, the possibility of restoring forests where they would exist under normal circumstances if there were no people is considered, so as to re-stimulate the growth of degraded forests or to reforest deforested areas, but this does not apply to areas key to the development of agriculture or those where there are already cities.

Carbon sequestration includes: sequestration through afforestation, sequestration in the soil, direct injection of CO2 into the ocean depths, conversion of CO2 into carbonate minerals and geological sequestration, which is also the most significant. The goal is to collect CO2, remove it from the atmosphere and transport it to a safe storage facility. The largest potential reservoirs for CO2 storage are the seabed and geological reservoirs in the Earth's crust.

The new findings suggest that while forests can contribute to the fight against climate change, it is counterproductive to use them for the carbon offset market in the future, according to Crowther.

Crowtner adds that any additional emissions in the future will exacerbate climate change and extreme weather, destroying and impairing their ability to absorb carbon dioxide, which would negate the benefits of carbon offsets, he said.

The idea of offsetting carbon by simply planting trees "is now at odds with what the science advocates," says Crowther, who plans to attend the upcoming United Nations COP28 climate summit in Dubai to deliver a message to policymakers.

"This document, this research must destroy manipulative green marketing," he told Reuters.

Continuation of the 2019 study on forest restoration

The research is a continuation of an important study from 2019, which was also co-authored by Crowther. According to it, reforestation could remove approximately 205 gigatons of excess carbon dioxide from the atmosphere.

But the results of the research and the effort to plant a trillion trees, which was supported by the then US President Donald Trump, sparked controversy among scientists and environmentalists.

Many scientists and activists, including the Swedish activist Greta Thunberg, believe that trees are presented as an oversimplified "cure" for the climate crisis and could distract attention from efforts to reduce the use of fossil fuels, the main culprit of climate change.

More than 40 scientists write in the journal Science that a 2019 study may have "inflated" the carbon sequestration potential of reforestation by a factor of 4 to 5, if tree planting in non-forest ecosystems is taken into account, which is one of the omissions.

He believes that the latest figure presented by Crowther - 226 gigatons - also includes carbon accumulated in places that are "not suitable" for planting trees, namely high altitudes. He also believes that the authors rely excessively on the growth of forests in the savannahs, which he believes is impossible.

Crowther responds that while both the current and previous studies indicate where trees should be planted, that doesn't mean they should actually be planted there.

Precisely work out the process of forest restoration in order to be effective

The authors of the study point out that forest restoration must be precisely worked out in order to be effective.

Among other things, they believe that forests must be diverse and that mass planting of one type of tree should not be resorted to, as well as that forest restoration should serve the needs of local communities.

Crowther and his colleagues point out in their work that they believe that protecting existing forests is more useful than trying to "grow" them again.

Of the total carbon dioxide sequestration potential, only 39 percent would be from afforestation of bare areas.

Carbon offsets are used by companies or organizations that release greenhouse gases into the atmosphere, paying another entity and offsetting what they emit, thus reducing their net emissions.

To achieve net zero, all greenhouse gas emissions would need to be offset through carbon storage or sequestration.

Source: index.hr, 15.11.2023.