The Effects of Climate Change on Paddy Yields in Malaysia's Granary Areas: A Markov Chain Monte Carlo Approach

Paddy production systems are subjected to unique ecological and climatic conditions. This crop is cultivated in rainfed and irrigated lowlands, uplands and deep-water areas. In general, this crop can grow at areas with temperature between 20o–350C, rainfall 1000-2000mm/year and water level 10–15cm ((Silva et al., 2007; Oh et al., 2023; Ratyanake et al., 2023). Most of the world's paddy is produced in irrigated lowland rice systems, which contribute to 75% of the worldwide paddy crop, covering around 93 million hectares. Conversely, 19% of the world's paddy production comes from 52 million hectares of rainfed lowlands (Global Rice Science Partnership, 2013). Specifically in Malaysia, paddy is planted twice (cropping seasons) annually. The main season (humid weather, August-February) is based on a non-irrigation dependent system, whereas the off-season (dry weather, March-July) requires an irrigation system. There are 12 paddy granary areas in Malaysia andM mostly paddy produced hereproductions are coming from granary areas. There are 12 paddy granary areas in Malaysia.: Muda Agricultural Development Authority (MADA), Kemubu Agricultural Development Authority (KADA), Integrated Agricultural Development Area (IADA) KETARA, IADA Barat Laut Selangor (BLS), IADA Kerian, IADA Seberang Perak, IADA Seberang Perai, IADA Kemasin, IADA Rompin, IADA Pekan, IADA Kota Belud and IADA Batang Lupar. There are many factors effecting the paddy yield in these granary areas. Among the main factors is the climate change. As suggested by Zainal et al. (2014), the optimal temperature for paddy growth is very sensitive to temperature changes. Paddy yield production is found to decline steeply as the mean temperature exceeding 28oC. Meanwhile, rainfall variability is attributed to poor amount and distribution of rainfall and soil properties such as water holding capacities and poor fertility. The increase in temperature and rainfall during a main and offseason will decrease paddy yield by 12 percent and 31.3 percent, respectively in 20 years (Vaghefi et al., 2016). Keywords: Climate change, Granary areas, Markov Chain Monte Carlo, Paddy yield.