El Niño could intensify until February 2027, UN warns

The world is facing a double threat of rising global temperatures this year. Greenhouse gas emissions are driving climate change and increasing temperatures while the climate pattern known as El Niño has also begun.

El Niño is a climate phenomenon that can further increase temperatures in a world already experiencing extreme heat. A significant rise in temperatures could lead to more heat-related deaths.

According to a statement issued by the World Meteorological Organization (WMO), an agency of the United Nations, El Niño is expected to strengthen in the coming months and could remain strong until February 2027.

The WMO said El Niño is expected to reach its peak by the end of this year while its effects are likely to continue into 2027.

The organization said the phenomenon has already begun and is expected to intensify significantly in the coming months affecting temperatures and rainfall patterns and potentially causing floods, droughts and extreme heat.

What are El Niño and La Niña?

El Niño is a climate phenomenon in which a large part of the Pacific Ocean becomes warmer than normal contributing to a rise in global temperatures. In contrast, during La Niña, Pacific Ocean temperatures become cooler than normal.

The world experiences these two phenomena roughly every three to seven years although La Niña events generally last longer.

What happens during El Niño?

Normally, easterly winds push warm surface water in the tropical Pacific toward Australia and Indonesia and away from South America. As a result, warm water accumulates in the western Pacific while cooler water from deeper levels rises to the surface in the eastern Pacific.

During El Niño however, these easterly winds weaken allowing warm water to spread across a larger part of the Pacific Ocean. During La Niña, the easterly winds become stronger than normal causing surface waters in the eastern Pacific to become cooler.

How will El Niño affect global temperatures?

Scientists say global temperatures have already increased significantly because of fossil fuel use but El Niño could push temperatures even higher. UN Secretary-General Antonio Guterres said El Niño is surprising the world with its effects.

He noted that ocean temperatures are rising, overall temperatures are increasing and the world is facing growing risks from unusual weather conditions. The last major El Niño occurred in 2023 contributing to 2024 becoming the hottest year on record.

This time El Niño is expected to peak toward the end of the year. However, heat stored in the oceans is released into the atmosphere more slowly which could contribute to higher global temperatures in the following year.

According to the WMO, the effects of El Niño are already being observed in different parts of the world in the form of floods and droughts. These impacts could become more severe as the phenomenon strengthens.

More than 90 percent of the excess heat trapped by greenhouse gas emissions from fossil fuels and other human activities is absorbed by the oceans. The ocean’s ability to absorb heat is generally stronger during La Niña.

During El Niño however, some of the heat stored in the ocean is released into the atmosphere. This is one reason global average temperatures can rise by around 0.2°C during El Niño events. El Niño affects the global climate system in many ways.

In South Asia, rainfall during the monsoon season can decrease while some drought-affected regions of Africa may experience increased rainfall. El Niño can also increase the risk of tropical storms potentially affecting countries such as the United States, India, Bangladesh, Japan and South Korea.

The WMO has forecast above-normal temperatures from September to November with nearly every region of the world expected to experience warmer-than-normal conditions.