El Niño is a weather changer for much of the world. As we understand a little more of this phenomenon that begins in the tropical Pacific Ocean but reaches all continents through changes in the atmosphere and jet stream, we are learning to adapt.
El Niño was declared earlier this year and is now moving in a mild form, expanding out from its area of origin in the Pacific. In the Philippines, the Department of Science and Technology announced that El Niño will start affecting the country in June and peak by the end of 2014.
Here are 10 things about El Niño that may help us better understand and respond.
- Every 20 years or so there is an intense El Niño due to major sea temperature changes in the Pacific Ocean. This results in drought in Southeast Asia down to Australia, but also in parts of South America and Southeast Africa and increased rain or heat in several other areas. The droughts of 1982-1983 and 1997-1998 are the most memorable in recent decades with the sister event of La Niña following. (Map 1)
- We talk about the story of El Niño, as it was associated with the loss of the sardine shoals off Peru (east Pacific) at Christmas time. However, we don’t begin to worry about it in the Philippines until it emerges second quarter of the year in mid-Pacific Ocean, about 9,000 km away, and 6,000 km away from Peru. The Philippines (120-130oE) is in the western Pacific and is affected by the sea temperature differences as they are measured in the Niño 3.4 region (120-170oW, mid Pacific,) and not in the Niño 1 and 2 regions off the coast of Peru and Ecuador (80-90oW) in the east Pacific. (Map 2)
- The Oceanic Niño Index (ONI) that gives the sea surface temperature conditions in this region indicates the appearance of El Niño. If there is an increase of more than 0.5 above the normal temperature of the ONI, then El Niño is declared. This threshold of 0.5 was passed last April, May, and June and El Niño was duly announced. In 1997 the variance was 2.38 above the average.
- The effect of the warm air and weakening of the winds is now reaching the Philippines and will have greatest effect in November before weakening. Though announced in May before the rainy season began, when the rains came many farmers thought the threat was over, but not exactly. This impending drought, although much weaker than its predecessors, can still affect the harvests of small farmers who may have no fallback food source.
- We now understand better the time lag between when El Niño is declared in the mid-Pacific and when it arrives mid-Mindanao. A standardized cumulative precipitation index of the available water in the natural systems in Mindanao is aligned with the ONI. The time lag is identified as 197 days for the present event to hit Bukidnon, a province in central Mindanao (W Clavano, ESSC Report, June 2014). So the importance of understanding this time lag is that when El Niño is announced internationally, its impact is about six and a half months later in the Philippines.
- The warmer water of Niño 3.4 region never reaches the Philippines, but through the atmospheric movement, the impact is felt. The air passing over the warm sea slowly increases in temperature and moves westward. The winds and wind power are weakened. Typhoons are less likely to form though the rains can still be disastrous, and a storm surge like Yolanda (Haiyan) can’t happen during the months of El Niño.
The 2014-2015 El Niño is following the same pattern as the 1997-1998 El Niño in terms of area of origin and pattern of development in the eastern Pacific. This time, the threat is much less, and there is a 75% probability that there is going to be a water deficit of 30%. The rains are expected to weaken for eight months from July to February, and the impact in terms of reduced rains is seen as most critical in the Philippines in November at the peak of El Niño.
- When the warmer air passes over land such as the Mindanao land mass, it will affect areas differently. It will possibly have a lesser impact on the Agusan valley (in eastern Mindanao) because there is more available ground moisture and have a stronger impact on Bukidnon where there is more cropland on a plateau with the rivers set in canyons. If we take a village in the mountains (e.g. Bendum, an upland village in Bukidnon) where the annual average rainfall is 2,240 mm for 365 days, the impact of El Niño as presently calculated translates to a 30% deficit of 364 mm by mid-April.
- A limited response from government is to undertake numerous cloud seeding operations to induce rain in selected drought-affected areas where major crops are growing. Apart from the expense of cloud seeding, at around US$ 1,000 per flying hour, these are one-off activities. The Department of Agriculture is also distributing shallow tube wells, drought-tolerant crop varieties, and exploring the use of water saving technologies. However, these responses are limited to lowland contexts and upland situations are not considered.
- Crop alternatives have not been explained very well, but root crops such as sweet potato, cassava, and yam, even if they grow slower, are important for food security in many upland villages and farms. In light of the poor delivery of the Millennium Development Goals in the Philippines, this could be occasion to really build a strong response in support of poor farmers and building local food security, before the onset of an intense El Niño.
The severity of El Niño in 1997-1998 and subsequent lapse in ocean water temperatures rise is part of the reason for skepticism over the whole climate warming analyses and projections. Part of the explanation given is the subsequent cooling by the major La Niña that cooled the waters, dissipating the warmth deep within the ocean. But El Niño is always around and will be one of the forces fed by climate change.