What is the scale of deforestation and its role in climate change?

In the last decade, the largest amounts of deforestation occurred across  the humid tropics, mostly in Africa, followed by South America. The UN Food and Agriculture Organisation (FAO) estimates that around 420 million hectares of forest were lost  between 1990 and 2020 (or 178 million hectares net, i.e. taking into  account afforestation and the natural expansion of forests). The annual  rate of deforestation has since slowed but was still 10 million hectares  per year between 2015 and 2020. The most important driver of  deforestation is the global demand for agricultural commodities:  agribusinesses clear huge tracts of forest and use the land to plant  high-value cash crops like palm oil and soya, and for cattle ranching.

Land use change, principally deforestation, contributes 12–20% of  global greenhouse gas emissions. Forest degradation (changes that  negatively affect a forest’s structure or function but that do not  decrease its area), and the destruction of tropical peatlands, also  contribute to these emissions. As a result of deforestation and  degradation, some tropical forests now emit more carbon than  they capture, turning them from a carbon ‘sink’ into a carbon source.  For example, the south-eastern part of the Amazon Rainforest is now considered a net carbon source by scientists.