Oil palm on peat: A path to (inevitable) disaster
Oil palm cultivation on peatlands is detrimental to the environment. However degraded peatlands can be rehabilitated and incorporated into sustainable landscape management, says Marcel Silvius
Oil palm cultivation on peatlands is seen as an attractive option for many plantation developers in Southeast Asia. Not only is the land extensively available but the soils, despite the poor soil fertility, are somehow “working” for oil palm cultivation. Peatlands can therefore be perceived as lucrative and attractive for expansion of oil palm plantations.
So why then is oil palm on peat a path to disaster? We highlight two major impacts in this article. Firstly, peatland drainage for oil palm results in substantial carbon emissions. Secondly it results in flooding and land loss as a result of soil subsidence. We also offer some solutions.
“Peatland drainage for oil palm results in substantial carbon emissions as well as in flooding and land loss”
Peatlands are wetlands with a water-logged organic soil layer (peat) and hold 25% of terrestrial carbon or two times more than all the world’s forests combined. When peatlands are drained for cultivation they become net carbon emitters instead of active carbon stores. This already causes 6% of all global carbon emissions; almost one quarter of carbon emissions from the land-use sector. Southeast Asia’s degrading peatlands contribute to about half of this.
Another but generally overlooked issue is soil subsidence. Subsidence is the lowering of the soil surface as the result of compaction, shrinkage and loss of substance (carbon) due to oxidation and erosion. It is a well-known and inevitable phenomenon in all places in the world where peatlands have been drained. In the Netherlands, for example, over one-third of the country lies below sea level as a result of peat soil subsidence, with some areas as low as 6 to 8 meters below the sea. Salt water intrusion is an increasing issue. Still, drainage remains a prevalent practice supported by pump-operated drainage and extensive dike systems. It is highly questionable if such systems are feasible in the tropical peatlands of Southeast Asia, both in an economic sense and practically, considering the extensive areas involved and the huge quantities and peaks of precipitation. The peat subsidence rate in the Southeast Asia is 5 cm per year and the expected sea level rise from climate change will further exacerbate the problems. Lowland regions with extensive areas of drained peat soils stand to experience unprecedented flooding and land loss with severe socio-economic consequences.
Shift to wise use of peatlands
In Southeast Asia about 25% of plantations are currently on peat. To prevent aforementioned disasters there is an urgent need to strengthen awareness, understanding and capacity to manage peatlands wisely. This should involve the conservation of remaining peat swamp forests, also in view of their status of high conservation value areas. In addition, alternative land-uses will need to be developed for unsustainably cultivated peatlands.
One alternative is paludiculture: land management techniques that cultivate commercially interesting crops on rewetted peatlands. It requires species that are adapted to growing under very wet circumstances, such as indigenous peat swamp forest tree species like Jelutung (Dyera sp) which produces latex and Tengkawang (Shorea spp) which produces seeds with high quality oil. Over 500 native plant species are known from Southeast Asian peat swamps with potential for commercial uses.
Aquaculture of indigenous freshwater fish species can be another attractive land-use option in areas where many drainage canals must be blocked for hydrological restoration. Combinations and/or land-uses that are independent of the soil or water, such as chicken farming may also be considered. Such alternative uses have the potential to strongly benefit local communities.
Degraded peatlands can thus be rehabilitated and managed as an integral part of sustainable and integrated landscape management. For growers with existing plantations on peat it basically signifies the need to carry out long-term drainability assessments and to pro-actively remove of these plantations well before they are hit by flooding and land loss. The RSPO, in its recently adopted Principles and Criteria in relation to peatlands, recommends reconsideration of replanting two crop cycles before the drainage limit is reached. The RSPO also requires the avoidance of peatlands in new plantation developments.
Marcel Silvius is head of programme and strategy for wetlands & climate at Wetlands International www.wetlands.org