This article first appeared in The Edge Malaysia Weekly on August 22, 2022 - August 28, 2022

The Earth’s temperature has been changing since time immemorial. The period of low temperatures in the polar regions coincided with the glacial era, which resulted in a drop in global sea levels. This phenomenon was followed by an increase in temperature during the interglacial period that resulted in sea level rise.

During the Pleistocene era, sea levels in Southeast Asia rose up to 50 metres above the present height, as shown by the evidence found in Malaysia. This is the period of sedimentation. 

These changes in sea level affect the quality of the soil and subsequently, agricultural yield. 

Slowly but surely, global air temperature is on the rise again. This is made worse by human activities that increase greenhouse gas (GHG) emissions, especially CO2. The concentration of CO2 in the air increased from 250 parts per million (ppm) before the Industrial Revolution era to more than 400 ppm now. The presence of the extra GHG enhances global warming. 

The consequence of climate change is seen in the rise in sea level of a few millimetres per year, observed at these strategic locations in Peninsular Malaysia: Melaka (Pantai Puteri), Kelantan (Pantai Cahaya Bulan), Pahang (Integrated Agricultural Development Project [IADP] in Pekan) and Johor (Tg Piai). 

The expected sea level rise by the year 2100 is 0.52 metre to 0.98 metre. The phenomenon will have a negative impact on agriculture and threatens food security. For instance, rice production in the low-lying coastal regions of the peninsula will be reduced.

High temperatures also have a negative impact on the physiology of plant and animal health. Disease and pest infestation are related to weather conditions; so are soil fertility and crop productivity. Serious drought or heavy rainfall — like how it has been happening in recent years — has had a devastating impact on food production.

Due to global warming, air temperature in Perlis and Kedah sometimes rises to as high as 40ºC, which coincides with the dry season. Farmers are worried about the shortage of water to sustain rice production in the Muda Agricultural Development Authority (MADA) area of Kedah-Perlis plains, the main granary of the country. 

Currently, Malaysia’s rice self-sufficiency level (SSL) is 71%. With improved infrastructure, the SSL is expected to increase to a higher level by 2030. But with the aforementioned problems, the nation may not be able to sustain the SSL of 71%. A visit to Pendang, Kedah, in March 2020 showed that water level was insufficient. Rice plants turned brown due to lack of water to support their growth. 

The rise in temperatures also changes weather patterns. Serious floods occur more frequently in the country, such as those that hit Kelantan (2014) and Selangor (2021). Rainfall from Dec 17 to 24, 2014 in south Kelantan was 580mm to 1,760mm, which was half of the annual rainfall for the area; this was the immediate cause of the flood. 

Soil erosion was 100 times more than normal. Siltation of infertile materials seriously damaged farmlands in Kelantan, affecting crop productivity. It was reported that the flood in Selangor last year resulted in devastating landslides, soil erosion and siltation of debris, wreaking havoc on people’s lives and causing damage to farmlands, further threatening food security in the country.

In conclusion, the way to go forward is to:

Dr Shamshuddin Jusop is Fellow of the Academy of Sciences Malaysia and former professor of soil science at Universiti Putra Malaysia

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