Development of National Emission Factor for Rice Production System in Malaysia: A Step Toward Achieving Sustainable Development Goals

Abstract

Objective: Currently, methane (CH4) emissions from rice cultivation in Malaysia are calculated using the regional’s methane emission factor (EF) of 1.60 kg CH₄ ha⁻¹ day⁻¹, as Malaysia has not yet developed a national emission factor. The objective of this study is to generate a country-specific EF of CH4 emission from rice cultivation in Malaysian rice fields. The EF generated would then be used in future emission estimates and the country’s greenhouse gas (GHG) inventory reports to the United Nations Framework Convention on Climate Change (UNFCCC). Theoretical Framework: The establishment of a national GHG emission factor for rice cultivation in Malaysia is critical for accurate GHG inventory reporting and effective climate change mitigation. This study utilizes the Intergovernmental Panel on Climate Change (IPCC) guidelines to derive a country-specific emission factor, enhancing Malaysia’s compliance with international climate obligations and promoting sustainable agricultural practices. Method: A new national EF was developed from eleven rice planting seasons in rice granary areas (IADA Pulau Pinang, IADA Barat Laut Selangor, MADA and KADA) and non-granary area (Sik, Kedah). The EF was calculated from methane emissions from the new data sets, published journals and unpublished data from MARDI. For the new data set, methane gas (CH4) was measured using a static chamber method (Minamikawa et al., 2015). Sampling of GHG from the gas chamber is carried out in the field every 2 weeks and gas was analysed by a GC System Agilent 7890A gas chromatography. The daily methane flux and methane emission follow the methods by Habib et al. (2007), Fauzi et al. (2023) and the Guidelines for National Greenhouse Gas Inventories for Cropland (IPCC, 2006a). Results and Discussion: The national EF calculated from CH4 gas emissions over eleven rice planting seasons in Malaysia between 2012-2024 was 1.80 kg CH4 ha-1 day-1, which is higher than the current regional EF used (1.60 kg CH4 ha-1 day-1). However, the value is within the range of the default value of 1.30 kg CH4 ha-1 day-1 by the Intergovernmental Panel on Climate Change (IPCC) 2006 and 2.00 kg CH4 ha-1 day-1 (IPCC, 1996). Research Implications: The use of this new EF resulted in 12.49% increase in the national GHG inventory from the rice cultivation sub-sector as compared to using the current regional EF. This initiative is part of a comprehensive plan to enhance and strengthen GHG inventory reporting for Malaysia's agriculture sector, aiming to meet IPCC requirements and progress to Tier 2 status.