Peatland Drainage Could Worsen Climate Change: Study
Thu, October 21, 2021

Peatland Drainage Could Worsen Climate Change: Study



A new study showed concrete evidence of how draining peatlands would affect the global climate. Investigators utilized satellite data and determined that human-related disturbances in peatlands could threaten both nature and people.

The investigation of the effects of peatland draining in Southeast Asia was led by experts at the Massachusetts Institute of Technology (MIT), a private research university in the US. Their findings showed that draining peatlands could result in air pollution, subsidence, and wildfires, all of which involved in climate change. Draining these wetlands could significantly increase atmospheric carbon and decrease the natural carbon storage of the planet. They published the results in the journal Nature Geoscience.



The Relationship between Peatlands and Climate Change

According to the International Union for Conservation of Nature, an international organization, peatlands are some of the most important ecosystems on Earth. These permanently wet ecosystems have critical roles in natural disasters, climate change, and drinking water. But because of human activities, many peatlands around the globe have been damaged. The damages release adverse effects in the environment – the direct opposites of their benefits. If more countries aim for the restoration of peatlands, many human communities will be spared from preventable repercussions.

The composition of peatlands is mainly organic matter. In these ecosystems, the decomposition of organic matter is exceeded by the production, which accumulates peat. Because of that, the flow of water is slowed that eventually causes flooding in the ecosystem. As long as a peatland is healthy, it can hold its flood and not harm the surrounding areas. But if drained, the decrease in water can upset the balance in the decomposition and production of peat.

The composition of peatlands is critical to its functions. First, peatlands can help control floods during rainy months. The accumulation of peat makes it difficult for water to move normally. Second, peatlands assist during dry months when drought can ruin farmlands. Since peatlands can store and regulate water, their presence near farmlands slows down the decline in soil wetness. Third, the coverage of peatlands acts like a barrier between freshwater and seawater. The ecosystems can also filter out contaminants in water. Thus, peatlands offer an excellent supply of drinking water.



And finally, peatlands serve as a natural storage of carbon. The greater the production of peat than the decomposition rate, the better peatlands perform in storing excess carbon. However, a disruption in peatlands can increase the decomposition rate. The increase will surge the carbon emission from the wetlands. So, damaged peatlands tend to be harmful to the atmosphere until the disruption is resolved.



Peatland Drainage in Southeast Asia Could Aggravate Climate Change

Investigators at the Singapore-MIT Alliance for Research and Technology, the University of Oregon, and MIT quantified the consequences of peatland destruction. They utilized satellite data to measure the effects of peatland drainage in Southeast Asia. Their measurement expressed disturbing consequences to nature and communities. The drainage of peatlands could also affect the future of other ecosystems.

In the study, the team gathered data from satellite sources. The data was collected from 2007 to 2011 and had been examined via Interferometric Synthetic Aperture Radar. The technique enabled the team to identify changes in the surface elevation with an accurate rate between millimeters and centimeters. This helped them quantify subsidence due to the destruction of peatlands and the amount of carbon gas released into the atmosphere.

“This is definitely a proof of concept on how satellite data can help us understand environmental changes happening across the whole region. This has really exciting management implications, because it could allow us to verify management practices and track hotspots of subsidence,” said Alison Hoyt, a principal investigator and professor of civil and environmental engineering at MIT.



The data revealed the surface elevation in 2.7 million hectares of peatlands. These ecosystems were mostly in Indonesia and Malaysia. The total area of peatlands in both countries could account for over 10% of the all peatlands in Southeast Asia. Satellite feeds detected subsidence in the peatlands and more than 90% of those ecosystems were shrinking. The average subsiding rate was nearly one inch per year or more than one foot per 15 years. The same subsiding rate was equivalent to the measurement of carbon dioxide emissions.

The cause of the subsidence of peatlands was not drainage alone. Investigators correlated the shrinkage issue to the diverse set of land use. The combination of drainage of peatlands, expansion of farmlands, and creation of canals for timbers contributed to the problem. In short, the combined ill-effects of human activities weakened the foundations of peatlands.

Aside from subsidence, peatland destruction in the region was associated with other adverse outcomes. The drainage could leave dry, flammable organic matter. This could start wildfires and burn down natural habitats. The fires might even threaten nearby human communities. Alternatively, the organic matter could simply decompose and emit carbon gas into the atmosphere. The decomposition would indicate mass loss, not just soil compaction.

According to the Food and Agriculture Organization (FAO) of the United Nations, peatlands have to be monitored and protected from human activities and harmful factors. The main reason why peatlands need protection is its role in the carbon cycle. Its role in that cycle can go either way: positive if healthy or negative if damaged. As a positive role, peatlands store excess carbon from organic matter and in the air. The gas is released in a more controlled manner to avoid its accumulation in the atmosphere. As a negative role, peatlands emit excessive levels of carbon gas into the air. The emission levels will quickly boost atmospheric carbon.



The FAO estimates that about 25% of the Earth’s peatlands have been degraded due to disturbances. These peatlands hold around 650 billion tons of carbon. That enormous amount of carbon is stored in 3% of the planet’s land area. And so far, approximately 5% of human-related greenhouse gas emissions are associated with peatlands, which have been degraded.

In this age, peatlands are not just for carbon storage. They are critical in managing floods and securing the supply of drinking water. If governments decide to put more effort into restoring peatlands, many cities will get more access to clean water. The water from healthy peatlands is free of salt and can go straight to water treatment facilities.