High-resolution satellite datasets show doubling of gross tropical forest carbon loss worldwide over past two decades

A large, international team of researchers has found that carbon emissions due to deforestation in tropical areas have doubled over the past two decades. In their paper published in the journal Nature Sustainability, the group describes using high-resolution satellite datasets to calculate the amount of tropical forest that has been cut down for agricultural use over the past 20 years.

Cutting down tropical forests leads to increases in carbon in the atmosphere in two ways. The first is due to carbon increasing in the atmosphere rather than being sequestered in trees. The second is the carbon released when trees are burned to clear land for growing crops. Prior research has shown that burning forested areas is the second-largest source of carbon emissions, behind the burning of fossil fuels. Prior research has also shown that in just the past 20 years, the world has lost approximately 10% of its worldwide forest cover.

In this new effort, the researchers suggest that prior efforts to measure the amount of carbon emitted into the atmosphere due to deforestation have been misguided. They note that efforts such as the Global Carbon Budget 2021 were based on limited data that overlooked small-scale deforestation and the movement of land-clearing into mountains, which is why those researchers found only slight declines in carbon loss due to deforestation.

The new team took a different approach. They obtained high-resolution satellite data for the years 2001 to 2020 and tracked tropical forest loss year by year. They found that there was far more loss than has been reported by other researchers and officials globally. They found losses in the Democratic Republic of the Congo, Indonesia, and most specifically, Brazil, which was responsible for the biggest losses. They also found that more forest has been cleared in mountain regions than previously thought, a significant finding because trees in these areas are thought to hold more carbon.

By measuring the amount of lost forest coverage and calculating the amount of carbon sequestering loss and emissions increases, the researchers found that carbon emissions due to deforestation have more than doubled over the past two decades.

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