Agricultural Land Conversion Scenarios And Implication On Carbon Stock Changes | FAKULTI PERHUTANAN DAN ALAM SEKITAR
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Agricultural land conversion scenarios and implication on carbon stock changes

Integrating climate change measures into the national policies, planning and strategies has been embedded under the United Nations Sustainable Development Goals (SDG) – Goal 13: Climate Action. Various climate mitigation strategies are progressively undertaken across the globe in response to global warming issues and in pathways to limit the temperature increase to no more than 1.5oC. This is also in line with the objectives and strategies of the Paris Agreement as the major step forward for global action under the United Nations Framework Convention on Climate Change (UNFCCC). An important issue that has been debated is the gap between carbon sequestration and carbon emission. It is targeted that emissions must achieve net-zero by the mid-century, e.g. the International Energy Agency (IEA) Net Zero Scenario by 2050 to limit the 1.5oC temperature increase. Among the strategies is to focus on the forest-based mitigation actions, highlighting the potential for carbon sink and to reduce CO2 emissions which is a major greenhouse gas (GHG) to the atmosphere.

The importance of tropical forest protection is inevitable as tropical forests play a major role in the process of carbon sequestration for climate mitigation. The forest-based strategies in climate mitigation include deforestation, forest restoration and sustainable management of forests. On average, carbon stock of primary forests is about 141–159 Pg C (billion tons of carbon) and can store 35% more carbon. Deforestation and allowing for secondary forest growth would contribute to negative carbon emission between 2016 to 2100 by about 120 Pg C. However, land use changes may influence forest and soil carbon content, i.e. the carbon stocks. Changes in land use may have implications on carbon cycles through the emission of CO2. On another note, under the Eleventh Malaysia Plan, the country aims to pursue a sustainability growth and resilience through adoption of low carbon approach. Malaysia aims to reduce the energy consumption and carbon emission through the implementation of several strategies such as increasing the use of biofuel. It has been apparent that the oil palm plantations in Malaysia have expanded to fulfil the global demand for palm oil-derived biofuels. As a result, the oil palm plantation expansion rate in Malaysia has extended to approximately 0.15 million hectares per year. Another issue of concern is the conversion of primary forest into oil palm plantation development as land use change is often associated with changes in carbon stocks. Carbon that is emitted into the atmosphere can result in significant GHG emissions that could negate the benefit of using palm oil-derived biofuel. Previous findings have highlighted the impacts of converting tropical forest and peatlands into oil palm plantations, i.e. the associated carbon debt and carbon balance impacts of land use changes related to life cycle of Malaysian palm oil plantation. On the other hand, some land use conversions for oil palm plantation establishment would result in carbon savings. Notwithstanding this, the contribution of oil palm in reducing potential carbon emission has been similarly debated.

Other agricultural land conversions have also been noticeable most typically with regard to their carbon stocks. In fact, all types of land uses may act as a CO2 source or sink while the soil organic matter and vegetation have important roles in terrestrial carbon uptake. For instance, the changes in biomass carbon stocks in tree crops (e.g. rubber, cocoa and coconut) and forests in Malaysia, have a great implications for carbon emissions and total carbon balance. Impacts of deforestation on carbon budgets have been known including land conversion for crops such as rubber, cassava, coconut, sugarcane, rice and banana, among others. While oil palm is at its most productive on a per hectare basis when tress are planted as a monoculture, intercropping with black pepper and banana in improving plantation diversity has also been introduced. Regardless of the conversion types, emissions gap still requires particular attention in the mitigation strategies so as to reduce the rate of emission and enabling carbon sequestration. Clearly, land conversion has an important role in influencing the soil and vegetation carbon stocks and hence the intensity of greenhouse gas emission in particular CO2. In essence, conversion of tropical forest for agricultural lands would not be recommended, however converting from one crop land into another type would be considered whenever CO2 emission rate is tolerable.

Carbon cycle of terrestrial AFOLU (agriculture, forestry and other land use) ecosystems (adapted from Maniatis and Mollicone, 2010)

Tarikh Input: 12/07/2023 | Kemaskini: 12/07/2023 | masridien


Universiti Putra Malaysia
43400 UPM Serdang
Selangor Darul Ehsan