Powerful El Niño could make 2027 the hottest year ever recorded

Researchers said the El Niño, now strengthening, is on course to be the largest in at least 150 years, according to the multidisciplinary science journal Nature.

If forecasts hold, the heat it releases from the ocean, combined with human-caused climate change, will also trigger extreme weather across much of the world.

Climate models project that this El Niño's peak will surpass the previous record by "truly a mind-blowing margin," according to Zeke Hausfather, a climate scientist at Berkeley Earth, a U.S.-based non-profit that hosted the briefing.

He said it is "not outside the realm of possibility" that the event, combined with climate change, could push global average temperatures in 2027 as high as 1.7°C above pre-industrial levels, bringing the planet to the edge of breaching the 1.5°C threshold that governments pledged to avoid under the Paris Agreement.

"For context, the gap between the strongest and the fifth strongest El Niño of the past 150 years is only about 0.5C. The models are forecasting something outside the envelope of anything we have ever observed."

World Meteorological Organization's air temperature forecast for the period from June to August, with red areas indicating above-normal temperature increases. Photo by World Meteorological Organization

The U.S. National Oceanic and Atmospheric Administration said El Niño is now underway as warm water shifts eastward toward the normally cool waters off Peru's coast.

The agency puts the odds of it developing into a very strong event later this year at 63%, nearly twice the probability it had estimated in May.

U.N. Secretary-General António Guterres said it is a reminder of the need for a shift away from fossil fuels towards renewable energy.

"The world must treat it as the urgent climate warning it is. El Nino conditions will pour fuel on the fire of a warming world."

American technology magazine WIRED said research by climate scientist Justin Mankin found that the 1997-1998 El Niño caused economic damage that reduced global growth by approximately "$5.7 trillion" in the years that followed.

If current projections hold, the episode now unfolding could result in losses of around "$10 trillion" by 2032, Mankin said.

According to the World Resources Institute (WRI), El Niño can also intensify marine heat waves, posing particular dangers in oceans already warmed by climate change.

These temperature spikes can damage seagrass meadows and kelp forests, raise stress and disease risks in aquaculture, and disrupt the timing and distribution of plankton and fish populations.

Coral reefs are especially at risk; past strong El Niño events, like in 1997-1998 and 2015–2016, triggered major global bleaching episodes that weakened ecosystems underpinning fisheries, tourism, and coastal protection.

For communities that rely on the ocean, these ecological disruptions hit incomes, nutrition, government revenues, and coastal resilience hard, particularly in developing coastal and island nations. A Super El Niño would therefore destabilize the very ocean systems that millions of people depend on for food, livelihoods, culture, and protection from climate impacts.

WRI also flagged the fuel and fertilizer disruptions linked to the Iran-U.S. conflict, saying a strong to very strong El Niño would heighten the risk of drought, heat, flooding, pasture stress, fisheries disruption, and regional crop losses in parts of the world, risks that become more severe when farmers have fewer resources to respond with.

According to Reuters, the weather phenomenon is likely to cause drought in parts of Asia and heavy rainfall in parts of South America, threatening crops and food supplies.

Developing countries are particularly vulnerable as households spend a large share of their income on food and agriculture plays a significant role in their economies, raising the risk that central banks will need to maintain tighter monetary policy for longer.

Central banks in the Philippines, Indonesia, Korea, Pakistan, and Sri Lanka have already hiked interest rates at least once this year. A severe El Niño could keep borrowing costs elevated across the region through the start of the following year.

"El Niño is just going to make inflation more sticky," said Gary Tan, equity portfolio manager at Allspring Global Investments.

"People are forecasting rate hikes for the second half of the year, especially for the South Asian countries, which are kind of the most impacted by El Niño such as India, Indonesia, Vietnam, Thailand."

El Niño is a phase of ENSO, a cycle in which sea surface temperatures and winds in the Pacific alternate between the warm El Niño and the cool La Niña roughly every two to seven years. The most recent El Niño occurred in 2023-2024.