SINGAPORE - El Nino, a recurring weather pattern related to the warming of surface waters in the Pacific Ocean, is set to resume in 2023. 

I have always been concerned about El Nino leading to unprecedented heatwaves in Singapore and South-east Asia.

So much so that in 2019, I wrote an article for The Straits Times, titled Climate X factor.

I made an ominous prediction that the return of El Nino would bring a surge of warmth to an already overheated planet.

What is El Nino?

El Nino and La Nina are opposite phases of the El Nino-Southern Oscillation (Enso), a temperature variation between the ocean and the atmosphere over the central and eastern tropical Pacific.

El Nino is the warm phase, while La Nina is the cold one. They typically occur once every few years, lasting nine to 12 months, but sometimes even years. Their frequency is quite irregular, with the warm phase happening more frequently than its opposite.

The name El Nino comes from the Spanish word for “child” or “the Christ child”. It was first used by fishermen along the coasts of Ecuador and Peru to refer to a warm ocean current that typically appears around Christmas time and lasts for several months.

Fish are less abundant during these warm intervals, so fishermen often take a break to repair their equipment and spend time with their families.

But over the years, Enso has come to denote the more exceptionally warm intervals that not only disrupt fishermen’s lives, but climate conditions around the planet as well. 

Enso is one of the most important climate phenomena on earth due to its ability to change global atmospheric circulation which, in turn, influences temperature and precipitation across the planet.  

During the El Nino phase, there are above-average sea surface temperatures (SSTs) recorded in the central and eastern tropical Pacific Ocean. Rainfall increases there, but is reduced over Singapore. Low-level surface winds, which normally blow from east to west along the Equator, weaken or start blowing in the other direction.

La Nina cools the ocean surface, and below-average SSTs are recorded in the central and eastern tropical Pacific Ocean. There is less rain there, but rainfall tends to increase over Singapore. Regular, easterly winds along the Equator become even stronger.

The last three years have seen an unusual run of consecutive La Nina events, which have contributed to the unusual wet weather experienced in Singapore and South-east Asia. But these events have not sufficiently cooled the earth to offset the influence of climate change. The year of 2022 ranks as the fifth- or sixth-hottest year on record.

What happened during the last El Nino?

The last major El Nino event occurred in 2016. It affected more than 60 million people, particularly in eastern and southern Africa, the Horn of Africa, Latin America and the Caribbean, and the Asia-Pacific region.

It disrupted crop production, imposed societal distress and resulted in peak energy consumption.

Unprecedented heatwaves driven by this major El Nino event made 2016 the hottest year on record in Singapore and globally.

With a mean annual temperature of 28.4 deg C, 2016 was Singapore’s warmest year on record since 1929. During this event, seven records for the warmest calendar month were either broken or tied.

Notably, hot and dry weather spells affected Singapore and the Malay Peninsula from early March to April 2016.

The significantly drier conditions notably affected water supply sources in some parts of the region; water levels in the Linggiu Reservoir, which supplies water to Singapore, fell to low levels during the year.

Forest fires in Indonesia were worsened by El Nino. It resulted in the region’s worst haze episode on record.

In the aftermath of that event, 15 per cent to 20 per cent of the corals in Singapore died. The El Nino event caused sea surface temperatures to go up, resulting in accumulated heat stress that caused coral bleaching for around three months.

What will the 2023 El Nino mean for weather in Singapore and the rest of the world?

It is predicted that the return of El Nino will result in unprecedented heatwaves, making 2023 even hotter than 2022. 

El Nino occurs during winter in the Northern Hemisphere, and its heating effect takes months to be felt, meaning 2023 and 2024 are much more likely to set a new global temperature record.

El Nino is likely to push global average temperatures well above the 1.5 deg C threshold, which will significantly raise the risks of drought, floods, and extreme heatwaves. It will also increase the risk of food and water insecurity and poverty for millions of people worldwide.

Why is 1.5 deg C important?

The 1.5 deg C of warming will see extreme heatwaves, sea level rising, and the destruction of 70 per cent to 90 per cent of coral reefs. This is why the figure is so important, and why allowing the planet to heat beyond that could be disastrous for nature and humanity.

Under climate change, the impacts of El Nino events are going to get stronger. 

Severe drought leading to food insecurity, flooding, rains, and rising temperatures due to El Nino will cause a wide range of health problems, including disease outbreaks, malnutrition, heat stress and respiratory diseases.

Climate modelling results issued in early January by Australia’s Bureau of Meteorology indicated that the country could swing from three years of above-average rainfall to one of the hottest, driest El Nino periods on record, increasing the risk of severe heatwaves, droughts and fires. 

South-east Asian countries see significant climate-related problems during El Nino events, with India, Indonesia, the Philippines and Australia often experiencing deficient rainfall or drought.

Given the region’s extremely large population, its significant economic dependence on agriculture, and the preponderance of small-scale subsistence farms, any potential climatic threats to agricultural yields may have implications for regional food security. 

Food stocks are likely to be lower than normal going into 2023, so another round of poor harvests could be devastating. Resulting food shortages in most countries could drive civil unrest, while rising prices in developed countries will continue to stoke inflation and the cost-of-living crisis.

How can we be resilient to El Nino and climate change?

Resilience is tied to scientific discovery. The early warning provided by climate scientists in 2023 will enable governments in the region to discuss and implement El Nino-related contingency plans.

The 2023 El Nino may lead to governments pursuing a resilient, sustainable world earlier than previously thought. 

We know that El Nino and climate change present risks to nature, people and infrastructure around the world. These risks will increase with every small increase in warming, and reducing them is made more complicated by other global trends such as over-consumption, population growth, rapid urbanisation, land degradation, biodiversity loss, and poverty and inequity.

Striving for resilience means reducing exposure and vulnerability to climate hazards, cutting back greenhouse gas emissions and conserving biodiversity are given the highest priority in everyday decision-making and policies in all aspects of society.

These include energy, industry, health, water, food, urban development, housing and transport. 

Resilience involves everyone. Prospects for effective action improve when governments work with citizens, civil society, educational bodies and scientific institutions, the media, investors and businesses, and form partnerships with traditionally marginalised groups, including women, youth, indigenous people, local communities and ethnic minorities.

We must establish Singapore as a highly liveable, sustainable and resilient country, as a city of the future, and as a vibrant urban solutions hub – a living model that features cutting-edge urban solutions.

• Professor Benjamin Horton is the director of the Earth Observatory of Singapore at Nanyang Technological University.