El Niño is almost here, with scientists closely monitoring its development following the conclusion of its inverse counterpart, La Niña, in February. While El Niño is known to boost global temperatures, against the backdrop of the already warming planet, there are concerns that it could further push Earth towards destabilising climate thresholds. The United Nations, for instance, has warned about the growing probability of El Niño occurring in the upcoming months, which could result in elevated global temperatures and possibly new heat records. Likewise, Robert Rohde of Berkeley Earth estimates that 2023 is on track to be the second, third, or fourth warmest year on record for Earth.

Despite the cooling effect of an unusually prolonged La Niña, which lasted until earlier this year, the United Nations has declared that the past eight years have been the warmest on record. This is noteworthy, considering that almost half of this period was influenced by La Niña's cooling conditions.

Understanding the Climate Swing

What are the El Niño and La Niña phenomena?

According to the Met Office, El Niño and La Niña refer to fluctuations in the Earth's climate system. El Niño is characterised by the rise in sea surface temperature, typically observed in the central-east equatorial Pacific, occurring at intervals of a few years. This phase brings warmer-than-average weather to the tropical eastern Pacific. La Niña, the opposing phase of El Niño, occurs when the sea surface temperature becomes cooler than average. As a result, the tropical eastern Pacific experiences cooler than average weather. Together, the two phases are known as the El Niño-Southern Oscillation (ENSO).

What effect does it have on countries' weather conditions?

El Niño often brings warmer-than-average temperatures and reduced rainfall to some regions while causing increased precipitation and storms in others. During El Niño events, the warmer water causes the Pacific jet stream's strong air currents to shift further south and east. This leads to wetter weather conditions in southern US states and the Gulf of Mexico, while the northern US and Canada tend to be drier. Drought conditions are typically observed in regions like Asia, Australia, and Central and Southern Africa.

Conversely, during La Niña events, the opposite occurs. It often brings increased rainfall to regions such as Southeast Asia, northern Australia, parts of South America, and the southern United States, while some regions may experience drier conditions. La Niña can contribute to an increase in Atlantic hurricane activity. The cooler sea surface temperatures in the tropical Atlantic combined with reduced vertical wind shear can create favourable conditions for the development and intensification of hurricanes.

During El Niño, global temperatures tend to increase by about 0.2C and decrease by about 0.2C during La Niña.

How often do they occur?

El Niño and La Niña events usually happen every two to seven years. According to the National Oceanic and Atmospheric Administration, these phases can last anywhere between nine months to a few years. These phases do not necessarily occur in strict alternation, as La Niña events are less frequent compared to El Niño episodes.

What causes them?

While their exact causes are still being studied, El Niño and La Niña are understood to be primarily caused by changes in ocean temperatures in the equatorial Pacific. These changes are driven by complex interactions between the ocean and the atmosphere.

Recently, a new study found that the El Niño and La Niña events are exacerbated due to rising greenhouse gas emissions.

Dr Wenju Cai, the lead author of the study from Australia's CSIRO science agency, stated that "The current paper provides modelling evidence that climate change has already made El Niño and La Niña more frequent and more extreme" and that the models showed a "human fingerprint" from 1960 onwards.

Unravelling the Economic Toll of ENSO Events

In an alarming development, scientists have issued a warning that the global temperature could surpass the critical 1.5°C threshold by 2027. According to the World Meteorological Organization (WMO), there is a high probability of record-breaking temperatures over the next five years. Experts attribute the rising global temperatures to a combination of human activities and the emergence of El Niño.

"A warming El Niño is expected to develop in the coming months and this will combine with human-induced climate change to push global temperatures into uncharted territory," Professor Petteri Taalas, the WMO's secretary-general, said in the WMO report. Further, he stated that "This will have far-reaching repercussions for health, food security, water management and the environment. We need to be prepared."

In addition to the ongoing global warming crisis, a powerful El Niño event can contribute an extra 0.2°C to the average Earth's temperature. Further, ENSO can lead to severe storms, droughts, floods, and wildfires, which can have significant economic consequences. The El Niño event of 2015 and 2016, for instance, affected more than 60 million people in 23 countries. These climate phenomena have previously caused substantial damage, including:

  • Reduced agricultural output: It has been found that the El Niño climate cycle is responsible for widespread simultaneous crop failure in different regions of the world. Drought, flooding, pests, diseases, and temperature variations brought about by El Niño can negatively impact agricultural output and food security in affected regions. El Niño's occurrence in countries like India typically aligns with a weakened monsoon and higher temperatures in India, adversely impacting the country's agricultural sector and causing domestic food prices and inflation to rise. During the 2014-2016 El Niño phase, droughts in Canada and Asia led to crop failure, jeopardising the food security of over 60 million people.

    An assessment by the International Food Policy Research Institute (IFPRI) which examined  La Niña in Tanzania, found a connection between the 2011 La Niña event to food shortages, which resulted in an estimated 3 per cent decline in food access. It has been found that La Niña had a more significant impact on production compared to El Niño. Maize and rice production were particularly affected, with reductions of 6 and 7 per cent, respectively, attributed to La Niña, while El Niño caused a decrease of 1 per cent and 4 per cent.

    An assessment by the International Food Policy Research Institute (IFPRI) which examined La Niña in Tanzania, found a connection between the 2011 La Niña event to food shortages, which resulted in an estimated 3 per cent decline in food access. It has been found that La Niña had a more significant impact on production compared to El Niño. Maize and rice production were particularly affected, with reductions of 6 and 7 per cent, respectively, attributed to La Niña, while El Niño caused a decrease of 1 per cent and 4 per cent.

  • Impacting Economy: According to a quantitative study published by Eesti Pank, both El Niño and La Niña events can have detrimental effects on economic growth. However, the study emphasizes that these impacts occur in different locations, through various local weather conditions, under diverse climate regimes, and at different times. The effects can be immediate or emerge over a longer period. Likewise, Christopher Callahan and his colleagues at Dartmouth College analyzed GDP data from 1960 to 2019 for 147 countries to assess the economic impact of El Niño events. Their findings indicate a significant drag on economies for up to five years after an El Niño event. For instance, the 1982-83 El Niño resulted in a global economic cost of $4.1 trillion, while the 1997-98 event cost $5.7 trillion. The majority of these losses were borne by poorer nations in tropical regions, where the impacts of El Niño are most keenly felt.

    According to Christopher Callahan **“**El Niño is really costly and has economic implications that are a lot larger than previously understood.“ He says [These events] “produce persistent reductions in economic growth that go beyond a simple blip that countries recover from immediately.”

  • Public Health: ENSO has a dire impact on public health. During El Niño events, air quality deteriorated to hazardous levels in several Southeast Asian countries due to wildfires exacerbated by drought conditions. Indonesia declared a state of emergency as the air quality became dangerous, leading to the evacuation of populations and thousands seeking medical assistance.

    Previous occurrences of El Niño have had significant health impacts, particularly on food security in Africa. In 1991-1992, El Niño triggered a devastating drought in southern Africa, affecting nearly 100 million people. The world food crisis of 1982-84, considered the most severe on record, was also attributed to El Niño, resulting in widespread famines that affected large populations in Africa.

    Further, the changes in temperature, precipitation, and humidity associated with El Niño and La Niña events can create favorable conditions for the spread of certain diseases or affect the habitats of disease-carrying vectors. For instance, El Niño events in Colombia have been linked to outbreaks of insect-borne diseases such as malaria and dengue. Likewise, the World Health Organization (WHO) has found correlation between La Niña and dengue epidemics in Southeast Asia.

  • Commodity prices and inflation: El Niño events, characterized by higher temperatures and droughts, can affect global commodity prices. For instance, in Asia and the Pacific, nonfuel commodity prices can increase by approximately 5½ per cent over a year due to the combination of higher temperatures and droughts. Droughts caused by El Niño in countries like Indonesia can harm agriculture, resulting in higher prices for commodities such as coffee, cocoa, and palm oil. Reduced production and increased demand contribute to price hikes. Prices could also rise due to supply chain disruption and reduced agricultural output. These factors lead to higher import costs, especially for essential commodities, and contribute to inflationary pressures. The cascading effects of higher commodity prices can impact inflation as businesses pass on increased costs to consumers, reducing their disposable income and potentially fueling inflation in the economy.

  • Energy: El Niño and La Niña can have significant effects on the energy sector, influencing energy use, impacting fuel costs, and affecting specific energy sources. ENSO's impact on weather conditions influences overall energy usage by altering the demand for heating and cooling systems. Likewise, they also affect energy generation. For instance, El Niño can disrupt hydropower production due to drought conditions, resulting in lower water levels in rivers and reservoirs. This can impact the availability and cost of electricity, potentially increasing the reliance on other energy sources like fossil fuels. Renewable energy sources, such as wind and solar power, can also be affected. For example, In India, wind power generation peaks between June and September, which aligns with the period when the El Niño weather pattern typically occurs. During this time, the slowdown of wind speeds can potentially affect the power generation capacity of wind turbines.

    An industry executive described the slowdown of wind speed due to the El Niño effect in India as a "double whammy" for the industry, which is already facing the challenges of low tariffs as any decrease in power generation can have financial implications for wind power generating companies.

It is important to note that the specific effects of El Niño and La Niña can vary across different regions and depend on the intensity and duration of the event. Each country may experience unique consequences based on its geographic location and vulnerability to the associated weather changes. Thus interestingly, El Niño and La Niña do not always have a negative impact.

For instance, in the United States, El Niño typically brings diminished tornado activity in the Midwest; in Cambodia, the economy grows during a typical La Niña event; ample rainfall enhances soybean production in Argentina, a country that exports 95 per cent of its soybean yield and in an El Niño year, Canada generally experiences greater return from its fisheries.

However, overall, the detrimental effects outweigh the benefits. In this regard, a study conducted by the World Bank reveals that the negative consequences of El Niño on agricultural production generally surpass the positive effects of La Niña in other countries.

Navigating the Climate Crisis with Climate Intelligence

The escalating climate crisis, in conjunction with the challenges bought in by ENSO, poses significant challenges for countries worldwide. The importance of climate action and risk mitigation efforts in this regard cannot be overstated.

Dr. Wenju Cai thus emphasizes on the need for urgent climate action. He highlighted that their findings should serve as inspiration for mitigation and adaptation strategies and that “because the increased ENSO and its further strengthening will exacerbate the economic risks of global warming.”

Likewise, According to Justin Mankin, a researcher who studied the enduring impact of El Niño on global economic growth, the alignment of El Niño events and global warming tends to amplify their combined effects. He stated “Any preparations we can do on the adaptive side are absolutely essential, but it in no way discounts the importance of climate mitigation as the primary means to prevent additional damages.”

Countries globally should thus enhance their disaster preparedness, forecast services, and management capabilities. Above all, efforts should be focused on reducing carbon footprint. Climate intelligence, supported by accurate and reliable data, plays a crucial role in this regard. By improving forecasting accuracy and preparedness for El Niño and La Niña events, countries can enhance their resilience and drive better policy interventions which can help mitigate the losses associated with these phenomena.