Mongabay explains why draining peatlands to grow oil palms is not a great idea.

Peat is a type of soil composed of partially decayed organic material such as vegetation that accumulates over time in a water-saturated environment lacking in oxygen. Peatlands are characterized by a thick layer of peat, often several meters deep that can take thousands of years to form.

Peat swamp forests act as massive carbon sinks, and when they are drained, carbon that has been slowly captured over the centuries it takes the peat to form is suddenly released into the atmosphere. A group of scientists recently uncovered the world’s largest tropical peatland in the Congo basin, thought to store the equivalent of three years’ worth of the world’s total fossil fuel emissions. The draining of peatlands can also lead to widespread subsidence, or sinking, as the organic matter rapidly decompresses and decomposes, ultimately rendering land unsuitable for agricultural or community development, according to NGO Wetlands International.

Across Southeast Asia, peat swamp forests have been cleared, drained, and burned away, often replaced by monocrop plantations or construction projects. Malaysia and Indonesia’s vast peatlands have been significantly reduced by large-scale draining and drying, leading to huge forest and peat fires across the region – such as the 2015 haze crisis that scientists say may have led to the premature deaths of 100,000 people. The event subsequently led Indonesia’s President Joko Widodo to ban the clearance and conversion of peat swamps.