El Niño and La Niña Phenomena: What Are They and Their Effects?

Feeling hot, lately? You are not alone. El Niño has been present in the country since the latter half of 2023, and only became stronger and more mature as it persisted into 2024.

It is a phenomenon that has hogged the news headlines as of late, leaving many Philippine provinces and climate-sensitive sectors with droughts and dry spells. But what is El Niño, exactly, and what of its counterpart, La Niña?

The El Niño-Southern Oscillation

The El Niño-Southern Oscillation (ENSO) is defined by the World Health Organization (WHO) as a naturally occurring climate phenomenon. It is the interaction between the atmosphere and ocean that results in variations in atmospheric pressure and sea-surface temperatures in the tropical Pacific.

El Niño and La Niña pertain to their oceanic components and the Southern Oscillation, the atmospheric component. ENSO happens in irregular periods of about every two to seven years and exhibits three phases, namely El Niño, La Niña, and neutral.

El Niño and La Niña are warring climate patterns that see the unusual warming or cooling of ocean temperatures, which result in drier- or wetter-than-average conditions. These, then, globally affect the weather, ecosystems, economies, health, access to water resources, and more, depending on El Niño or La Niña's intensity, duration, time of year it progressed, and its relation to other climate variability modes.

El Niño

El Niño, characterized by the unnatural warming of surface waters, is associated with dry spells and droughts. Translating to "Little Boy" in Spanish, El Niño was once known as a local phenomenon in Peru and Ecuador among anchovy fishermen to describe the presence of warm ocean currents.

According to the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), this phenomenon temporarily resulted in large harvests of anchovies, but the abundance was short-lived as El Niño became stronger, diminishing the fish population.

Climatic indicators of El Niño, as per the agency, include delayed rainy season, early termination of the rainy season, a far tropical cyclone track, fewer tropical cyclones crossing the Philippine Area of Responsibility (PAR), and weak monsoon activity. In other words, you can expect the rainy season to start later than expected and be shorter than usual, with less rainfall, and fewer typhoons.

In the Philippines, the first quarter of the year saw near-average to warmer-than-average air temperatures experienced over most of the country due to El Niño. Way below to below-normal rainfall conditions were also experienced in most of the country in February, except for some areas in Mindanao, which saw near to above-normal rainfall conditions that led to flooding and rain-induced landslides. This March, several provinces in Luzon and the Visayas also experienced drought, dry spells, and dry conditions.

La Niña Watch

La Niña, characterized by the unnatural cooling of sea-surface temperatures, means higher than normal rainfall can be expected.

PAGASA's advisory on March 7 also stated that El Niño has shown signs of petering out and is anticipated to last until the March-April-May 2024 season. It added that there's a 55% chance of La Niña developing during the June-July-August season, compelling the agency to raise its ENSO Alert and Warning System to La Niña Watch.

Impacts of El Niño and La Niña

ENSO-related droughts and rainfalls brought on by El Niño and La Niña spare nobody, with the former's impacts notably evident in the agriculture sector.

In their infographic published via humanitarian information portal ReliefWeb on March 25, the United Nations Office for the Coordination of Humanitarian Affairs showed that the ongoing El Niño has affected over 29,000 Filipino farmers, most especially those in the Western Visayas. More than 32,000 hectares of crop area were also affected by El Nino, 6,900 hectares of which have no chance of recovery. A production loss of 44,800 metric tons was also reported, comprising mainly of rice (64%), corn (18%), and other high-value crops (18%) — amounting to a value loss of P1.7 billion.

According to a 2019 report by the World Bank, "Striking a Balance: Managing El Niño and La Niña in Philippines' Agriculture," ENSO's impacts on agriculture also have implications on the economy, with strong El Niño events leading to losses in the national gross domestic product (GDP).

Net food-consuming households in urban areas also suffer welfare losses due to El Niño. With decreased crop yields, wages of farm laborers are also reduced, compelling workers to look for non-farm jobs for income.

Meanwhile, La Niña’s effects result in water abundance, such as flooding and other rain-induced disasters. It also adds about 25 "hot" days to the country annually, which can lead to heat stress on livestock and higher costs for producers.

While policy interventions do not entirely neutralize the losses brought on by ENSO events, the World Bank said that simulated interventions can work in bringing down welfare losses and curbing poverty increases.

"Simulations show that 5.1 million Filipinos fall into poverty during a strong El Niño event, but irrigation, cash transfers, and removing rice import quotas can mitigate this," the report said.

"In the most ambitious scenario, where all interventions are implemented together, the poverty headcount would actually decrease during a strong El Niño. This shows there is tremendous potential to implementing national policies related to ENSO."