The El Niño Climate Anomaly – Impact on Food Security in the Asia-Pacific Region

A connection between ocean temperatures and food supplies may seem remote, but when the warm waters of ‘El Niño’ appear in the Eastern Pacific, half of the world has cause to worry. This ‘Little Boy’ – named after the Christ child in Spanish – can affect crops and food supplies over a wide arc from Brazil through Australia and the Philippines to East Africa. Nevertheless, although a warmer Pacific affects the climate in many places, the complexity of the phenomenon makes accurate predictions difficult.

A connection between ocean temperatures and food supplies may seem remote, but when the warm waters of ‘El Niño’ appear in the Eastern Pacific, half of the world has cause to worry. This ‘Little Boy’ – named after the Christ child in Spanish – can affect crops and food supplies over a wide arc from Brazil through Australia and the Philippines to East Africa. Nevertheless, although a warmer Pacific affects the climate in many places, the complexity of the phenomenon makes accurate predictions difficult.

Phenomenon’s complexity and possible consequences

A new occurrence of the ‘El Niño Southern Oscillation’ (ENSO) began in March 2015 [1], and there are signs that this one might be comparable to the biggest yet, in 1982-83 and 1997-98. The El Niño oscillation occurs when sea surface temperatures (SST) in the Eastern Pacific increase by more than 0.5ºC for at least five seasons [2]. It takes several months to gather strength but by August forecasters were predicting that this would be a ‘strong’ one, with SSTs possibly rising up to 2.0ºC above normal or more [3].

The map below shows the differences from average water temperatures in all the world’s oceans at that time. Besides the warming of tropical waters under El Niño, it shows that on this occasion there were also big increases of temperature in the Northern Pacific [4].

El Niño is known to affect food production, and that of rice – the world’s most important staple food – more than most crops. Its impacts are found to be most severe on poorer, smallholder farms, for which over 70 per cent of farmland relies on rainfall rather than irrigation [5]. However, the details vary with each cycle and they are hard to predict in advance as several factors intersect.

El Niño compounds the effects of worldwide climate change – which itself in turn makes an El Niño worse. Climate change refers to a major alteration of the world’s climates in one direction, caused by emissions of ‘greenhouse’ gases into the atmosphere. But although El Niño directly affects only one large region, following a cycle of successive warming and cooling of ocean waters every few years, the two phenomena interact.

The cycle begins when warm water in the western tropical Pacific moves eastwards along the equator from areas around Indonesia and the Philippines towards the north-west coast of South America [6]. The Western Pacific’s waters therefore themselves grow cooler – the opposite of those in the east.

El Niño leads generally to storms and floods around the Eastern Pacific and droughts further west [7]. Its impact on Central and South America is probably the most widely known but it affects all areas around the Pacific, and even as far across the Indian Ocean as the South Asian subcontinent and East Africa. El Niño occurs every two to seven years, with varying degrees of intensity and duration, and usually peaks at the very end of a year.

On the other side of the cycle there is a contrary phenomenon, in which the Eastern Pacific’s surface water falls sharply in temperature. This is called La Niña. Each of these major warming or cooling events is usually surrounded by four or five years when there are other surges, which are similar but less pronounced. Over those years, either El Niño or La Niña is said to be ‘dominant’, depending whether all the surges together increase sea temperatures or reduce them.

The Food Economy – El Niño’s First Casualty

El Niño’s impact on the food economy can be as complicated as the phenomenon itself, but it is nonetheless real. Usually, the world’s wheat prices will rise initially as drought reduces yields in major wheat-growing areas in Eastern Australia. Rice output will also fall due to droughts in the more westerly zones affected by El Niño, causing that crop’s prices to increase too.

Given its importance in many Asian diets, it is the increased scarcity and higher prices of rice that are likely to have the greatest impact on food security overall. Food supplies in South and South-east Asia are expected to be among the worst affected by climate change too, due to rising sea levels, coastal flooding and saltwater intrusion, potentially affecting some 3.5 to 5 million people. For example, Oxfam has warned that, ‘The Mekong Delta in Viet Nam accounts for around 50 per cent of the country’s agricultural production and is at severe risk of saltwater intrusion. It has been estimated that a sea-level rise of 30 cm, which could occur as early as 2040, could result in the loss of about 12 per cent of crop production.’

Oxfam also projects that, ‘By 2050, more than half of the Indo-Gangetic Plains of South Asia, a region which grows 15 per cent of the world’s wheat, may become heat-stressed for wheat, with a significantly shorter season for the crop.’ Occurrences of El Niño will only make these effects worse [8].

An El Niño pumps up heat from deeper ocean layers to the surface. Although it is quite separate from global warming, some of the resulting surface heat is released to the atmosphere, warming the air and adding to the overall rise in temperatures caused by global warming [9]. The planetary temperature record set in 1998 was partly ascribed to that year’s strong El Niño, which ‘gave an extra kick to an already warming planet’, superimposing the natural oceanic cycle on top of the greenhouse effect [10]. Conversely, it may also be that climate change affects the intensity of El Niño, even if not the frequency of its cycles. One piece of research concluded that under global warming, ‘the likelihood of super El Niños doubles from one every 20 years in the previous century to one every 10 years in the 21st century.’ [11]

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The year 2014 recorded the highest annual global surface air temperatures, and the annual State of the Climate report emphasised it was the oceans that drove this record [12]. One of the report’s authors was quoted as saying that the effect will be very long-lasting: ‘Even if we were to freeze greenhouse gases at current levels, the sea would actually continue to warm for centuries and millennia, and as they continue to warm and expand the sea levels will continue to rise.’ [13]

The small island states of the tropical Western Pacific are thought to be among the most vulnerable to climate change. A recent study estimated that air temperatures there could rise by 0.5–1.7ºC by the end of the 21st century under the strongest mitigation policies for climate change, and 2.0–4.5ºC if there is no mitigation, compared with 1961-90 averages. This is on top a 0.61ºC global average temperature rise already recorded since the late 19th century [14].

It is less generally agreed what effect El Niño has on maize yields and prices. Some say that yields tend to fall and prices to rise, and others say the opposite. This is because maize is grown in many different zones, some of which – in the Americas – experience greater rainfall under El Niño, while others, such as East Africa and South-east Asia, tend to find droughts.

In general, the yields of soya beans – a major export crop in South America – tend to rise, leading to lower world prices. Among other tropical export crops, the prices of palm oil – grown largely in such countries as Indonesia and Malaysia – tend, like those of rice, to rise while yields decline. Paradoxically, this pushes soya bean oil prices up in its wake, even if the bean’s crops are larger and its prices consequently lower. Cotton has a similar tendency of lower output and higher prices, mainly due to drier weather in India, a major cotton-exporting country [15].

The consequences for food security can therefore be compared in the different regions affected by El Niño. In 2015 there was a particular fear that rainfed paddy rice production in South and South-east Asia could be affected, as rains were reported to be ‘below average and erratic’ in several places, including parts of Cambodia, North Korea, Laos, the Philippines, Thailand and Vietnam. But in that region more widely, the early forecasts for 2015 cereal harvests were reported in July 2015 to be ‘uncertain’ due to El Niño: ‘no precise quantitative association between the occurrence of El Niño and its impact on agricultural production can be deduced. Its impact on crops very much depends on the timing and intensity of the phenomenon.’ [16]

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El Niño’s impact is often clearest in the island states of the Philippines and Indonesia. In both of them rice is the main food crop but they usually import quantities of it, even in good years. In Indonesia the main 2015 rice crop was harvested by the middle of June and so it was little affected by El Niño [17]. But by July, ‘concerns over the possible impact of El Niño on the 2015/16 secondary season crop, currently being planted’ led to anticipatory increases in market prices [18]. At the same time it was reported that production prospects had deteriorated in the Philippines, mostly on expectations of reduced rainfall due to El Niño [19].

It was also thought that dry weather could affect winter wheat in important growing areas in Australia as well as the first and second season crops of maize and beans in Central America. In the main South American arable areas in Argentina, southern Brazil and Uruguay, it was thought that ‘heavy rains late in [2015] may delay plantings of the cereal crops, to be harvested from March onwards’ [20], thereby most likely also causing a shortfall in production.

Uncertain future

Nevertheless, in the present state of knowledge it is risky to attribute any trends in agriculture or food security too firmly to El Niño (or La Niña). As a recent newsletter of the U.N. Food and Agriculture Organisation (FAO) warned:

‘No precise quantitative correlation between El Niño’s intensity and its impact on agriculture has been probed. Its impact on crops depends on timing and duration, as well as climatic modifications produced by El Niño together with the sensitivity of the … crops during the peak period of influence of the event.’ [21]

In a more exhaustive study, the FAO observed that only a ‘weak correlation’ had been

‘found between the intensity of an El Niño event and drought conditions at global level… For instance, El Niño 1997/98, defined [as] “the climate event of the century” did not have major impacts on the agricultural areas of the world… El Niño 1991/92 caused drought in approximately 350 million hectares while El Niño 1997/98 affected 80 million hectares (77 percent less).’

The issue lies in the timing of El Niño, in particular the time of year when it begins, and whether it occurs during a period of the cycle when the Eastern Pacific’s surface water is generally warmer than average (called ‘El Niño dominance’) or generally cooler (‘La Niña dominance’). According to the same study,

‘If our hypothesis of El Niño/La Niña dominance cycles is correct, it would not be sufficient to forecast El Niño or La Niña years to anticipate drought impacts on agriculture but it would be necessary to know if the event would be under El Niño/La Niña dominance.’

It concluded that it was multi-year cycles under El Niño dominance, rather than a single El Niño event in itself, that were associated with more of the world’s agricultural area being affected by drought [22].

It is not yet clear whether 2015 and 2016 will belong to a period dominated by El Niño or La Niña. The previous year (2014) was neutral overall and it followed several years of La Niña dominance. If the current El Niño turns out to be a strong one, it seems reasonable to suppose that it will start a new period of El Niño dominance, implying greater impacts on agriculture and food security. However, the scientific evidence is too complicated and uncertain to make any firm prediction at this stage.

1. FAO, Food Outlook, Rome, May 2015, p. 25.

2. L’Heureux, M., M. Halpert and G.D. Bell, 2015: Oceanic Conditions [in ‘State of the Climate in 2014’]. Bull. Amer. Meteor. Soc., 96 (7), S91.

3. Climate Prediction Center/NCEP, ‘El Niño/Southern Oscillation (ENSO) Diagnostic Discussion’, 13 August 2015, www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.html.

4. Reproduced from: Climate Prediction Center/NCEP, ‘ENSO: Recent Evolution, Current Status and Predictions’, 10 August 2015, p. 7.

5. DeYoung, C., and A. Seggel, ‘Understanding the Impact of Climate Change on the El Niño Southern Oscillation and its Implications for Fisheries and Food Security on a Global Scale’, undated presentation from the FAO, p. 7.

6. Live Science, ‘What Is El Niño?’, 2 December 2014, p. 1.

7. Lemonick, M.D., ‘Global Warming-El Nino Link Stronger but Still Not Proven’, Climate Central, 3 January 2013, p. 1.

8. Oxfam International, ‘Can’t Afford to Wait: Why disaster risk reduction and climate change adaptation plans in Asia are still failing millions of people’, Briefing Note, November 2015, p. 3.

9. Oskin, B., ‘Brace for Record Heat as El Niño Approaches’, Live Science, 2 June 2014, p. 2, www.livescience.com/46049-el-nino-record-hot-temperatures.html.

10. Lemonick, M.D., ‘Global Warming-El Nino Link Stronger but Still Not Proven’, Climate Central, 3 January 2013, p. 2.

11. Kahn, B., ‘Climate Change could Double Likelihood of Super El Ninos’, Climate Central, 19 January 2014, p. 1.

12. Blunden, J., and D.S. Arndt, Eds., 2015: Abstract [in ‘State of the Climate in 2014’]. Bull. Amer. Meteor. Soc., 96 (7), Sxvi.

13. Johnson, G.C., quoted in ‘Warming of oceans due to climate change is unstoppable, say US scientists’, Guardian, London, 16 July 2015. Johnson was one of the editors of Ch. 3, ‘Global Oceans’, in ‘State of the Climate in 2014’.

14. Wang, G., and others, ‘Unambiguous warming in the western tropical Pacific primarily caused by anthropogenic forcing’, International Journal of Climatology, 2015.

15. FAO, ‘GIEWS Update: El Niño Southern Oscillation (ENSO)’, 4 June 2015, pp. 1-3; Rice, A., ‘How Might El Nino Affect Crop Prices?’, www.agweb.com/article/how-might-el-nino-affect-crop-prices-NAA-alison-rice/, 15 May 2015; Pidcock, R., ‘New study links El Niño to poor crop harvests worldwide’, Carbon Brief, 15 May 2014, pp. 1-2.

16. FAO, ‘Crop Prospects and Food Situation’, Rome, July 2015, p. 23, www.fao.org/giews/English/cpfs/I4773e/I4773E.html.

17. FAO, ‘GIEWS Update: El Niño in Asia’, 29 July 2015, p. 6.

18. FAO, ‘FPMA Bulletin: Monthly Report on Food Price Trends’, 10 August 2015, p. 4.

19. FAO, ‘Crop Prospects and Food Situation’, Rome, July 2015, p. 7.

20. FAO, ‘GIEWS Update: El Niño Southern Oscillation (ENSO)’, 4 June 2015, pp. 1 and 3.

21. FAO, ‘GIEWS Update: El Niño in Asia’, 29 July 2015, p. 7.

22. Rojas, O., and others, ‘Understanding the Drought Impact of El Niño on the Global Agricultural Areas: An assessment using FAO’s Agricultural Stress Index (ASI)’, FAO, Rome, 2014, pp. 37, 38 and 25.