At least one Southeast Asian nation – Thailand – has declared the arrival of La Niña in early August. Others suggest a 70 per cent chance of La Niña conditions between August and October 2024. Generally, crop-producing countries welcome the advent of La Niña (“little girl”), but given some negative impacts, the phenomenon is usually a double-edged sword.
La Niña is welcome after the heat waves and drought brought by the 2023–2024 El Niño, which was recorded as one of the five strongest on record. It impacted agriculture, particularly rice production, in Southeast Asia. El Niño was declared to have ended by May 2024. Unlike El Niño, La Niña is typically associated with cooler and wetter weather that could bring favourable growing conditions for crops. La Niña usually succeeds an El Niño (especially if the latter is considered strong), but not always.
The La Niña phenomenon is characterised by unusually low temperatures. It typically occurs every 3–5 years or so, and is due to the periodic cooling of sea-surface temperatures across the east-central equatorial Pacific Ocean. It can also occur over successive years and last six to 24 months.
La Niña’s impacts are nearly the opposite of El Niño’s. It can intensify rain and heat patterns compared to when the El Niño-Southern Oscillation (ENSO) is in the neutral phase. Some climate authorities are cautious; Indonesia’s, the Philippines’, Vietnam’s and Malaysia’s state weather bureaus are monitoring potential storms and flood risks which are projected to start in August, and in the case of the Philippines, increased tropical cyclone occurrence.
Climate agencies caution, however, that as sea surface temperatures reach record-breaking levels in 2023–2024 under the influence of climate change, there is a departure from historical global patterns of heat transfers associated with ENSO. It is thus challenging to predict how this anomalistic increase in global sea surface temperatures may affect future La Niña and El Niño events. Research has shown, however, that the two events have become more frequent and extreme due to climate change.
Historically, La Niña has resulted in increased rainfall in parts of Southeast Asia, particularly in the Philippines, Indonesia and Malaysia (see Figure 1). Many of the region’s maritime countries experience more rain from September to November and again from March to May. However, rainfall is reduced in the Philippines and Indochina between June and August.
Additional precipitation coinciding with planting seasons may improve soil moisture, thereby benefiting crops, but higher-than-average rainfall and wind systems may result in floods or more destructive typhoons. Depending on the stage of the agriculture production cycle, this could result in loss of fertile topsoil/ fertiliser, seeds being washed away, landslides, poorer-quality crops, crop destruction, or livestock mortality.
Based on historical records, the main rice-producing countries – Indonesia, Vietnam, and Thailand – have often benefited from higher rice production during “strong” La Niña years (see Figure 2).
Put Up Your Umbrella
Figure 1: Typical rainfall changes in Southeast Asia based on limited historical La Niña occurrences (between 1979 and 2021) for Sep–Nov, Dec–Feb, Mar–May and Jun–Aug.
Bigger Rice Harvests (Usually)
Figure 2: Rice Production (in million metric tonnes) between 1995 and 2022 overlaid with La Niña and El Niño periods in Southeast Asian nations, with stars indicating years where production increased.
Notably, locations impacted by last year’s strong El Niño may have experienced detrimental environmental, social and economic effects. This is likely to affect the productivity of subsequent planting seasons. For example, soils compacted due to heatwaves and drought in 2023–2024 may have limited capacity to absorb rainfall, leading to higher runoff and causing floods. Farmers already reeling from economic losses due to low yield may find it challenging to afford sufficient seeds and other inputs for the next crop cycle. This could curtail the abilities of farmers to maximise the dividends from La Niña.
La Niña typically has an impact on the global supply of staple grains, as it brings dry conditions and low yields to Argentina (affecting corn, wheat, and soybean) and Brazil (affecting corn and wheat). Both countries are major affordable grain exporters. Sometimes, however, this decline can be offset by agriculture gains in China, India, Australia and parts of North America as a result of beneficial weather (see Figure 3), though the timing and strength of precipitation matters. Flooding during harvest periods could result in lower yields.
Southeast Asia is a large and fast-growing importer of cereals and oilseeds. Indonesia is among the world’s top three wheat importers, and the Philippines is among the top ten. Many Southeast Asian countries are net importers of corn (Figure 4). Malaysia and Vietnam import approximately 100 per cent and 75 per cent of their corn, respectively. Southeast Asia’s wheat and corn supplies are mainly from Argentina and Brazil. Wheat is used for food and feed, while most corn is used for feed. Any global supply shortage would increase the price of meat in Southeast Asia. It would also impact food trade. For example, Vietnam is the third largest seafood exporter in the world, more than half of which is farmed fish and shrimp which depend on imported feed.
Wet Dry Wet
Figure 3: Net wet and dry regions and timing globally as a result of La Niña
While La Niña typically leads to above-average precipitation in parts of Southeast Asia and is often a boon to agriculture, this is not a guaranteed trend. Climate change has shifted ENSO dynamics; its impact on La Niña – and future El Niños – is yet unknown. One thing known is that climate change has made weather as a result of La Niña more extreme, and this may increase risks of flooding, especially in low-lying agricultural zones. If rainfall coincides with sensitive periods in the crop cycle, La Niña could also result in substantial damage to mature crops and worsen pest and disease outbreaks.
Boon or bane, Southeast Asian nations should be proactive to mitigate risks and capture potential benefits. Rather than just being glad that water reservoirs may be refilled, governments should assist farmers to recover from last year’s El Niño-related challenges quickly – with extension (farmer assistance) services and favourable credit for inputs – so that they are ready to maximise gains should they eventuate. Furthermore, policymakers should also prepare for potential meat price inflation and trade disruptions due to grain yield decline in La Niña-impacted regions in Latin America. Over the longer term, policymakers will also need to invest in improving R&D for climate-resilient crops, ensuring the long-term sustainability and resilience of food in the region.
This article was first published in Fulcrum, ISEAS – Yusof Ishak Institute’s blogsite.
