A potentially powerful El Nino is developing in the Pacific Ocean and could alter weather patterns around the world in the coming weeks. Forecasters warned it could be one of the strongest on record.
According to Paul Roundy, professor of atmospheric and environmental sciences at the State University of New York at Albany, “there is a real possibility of the strongest El Niño event in 140 years”.
The World Meteorological Organization (WMO) expects El Nino conditions to emerge soon and continue at least through the winter. Depending on its strength and duration, the climate event can cause drought, floods, heat waves and disruption of food and water supplies in many areas.
UN Secretary-General Antonio Guterres said, “The world should take this as an urgent climate warning.” “El Nino conditions will add fuel to the fire of a warming world.”
What is El Nino?
El Nino is a naturally occurring climate pattern that occurs every two to seven years. It begins when the trade winds over the tropical Pacific weaken, allowing warm water to pool in the Pacific Ocean.
Although the area of warming is about the size of the continental United States and occurs only in one area, its effects can be felt around the world.
“By changing the tropical atmosphere, you can change the atmosphere further away in the mid-latitudes, which is why we care about it so much, even though we’re potentially thousands and thousands of miles away,” Gavin Schmidt, director of the NASA Goddard Institute for Space Studies, told DW.
This has triggered a global chain reaction, he said, with El Niño becoming “the first atmospheric domino to fall”.
What effects are expected?
Those responses vary dramatically from region to region. In some places, this means increased risk of drought; In others, floods.
Parts of Central America, Asia, Africa, and Australia often become hotter and drier during El Niño years. The resulting water shortage can affect agriculture, hydropower generation and drinking water supplies. In Honduras, officials estimate that about 75 municipalities could face severe drought conditions. The country’s capital Tegucigalpa has already declared a water emergency.
In other parts of the world, the risks are reversed. In parts of the Pacific coast of South America, El Niño can bring torrential rainfall and devastating floods.
Its consequences can persist for a long time even after the rains stop or the reservoirs dry up. El Nino is linked to crop failures and potentially economic losses worth trillions of rupees. During the 2015–2016 El Niño, poor harvests left millions of people around the world in need of food assistance.
Forest fires are also a growing concern. Scientists have warned that El Nino could increase the risk of extreme heat and drought conditions, which could lead to wildfires in Australia, Canada, the United States and the Amazon rainforest.
Hurricanes, reefs and Atlantic hurricane season
El Nino plays a large role in tropical storm activity.
Scientists expect the Atlantic hurricane season to be less active than average this year. El Niño conditions increase wind shear over the Atlantic, making it more difficult for storms to form and intensify.
“The waters in the central and eastern tropical Pacific are beginning to warm,” said atmospheric scientist Brian Tang. “Typically that’s when we have an El Niño that develops, especially during hurricane season, which suppresses clouds, hurricanes, rainfall and tropical cyclones in the Atlantic.”
But fewer storms do not necessarily mean less danger. Once a storm reaches hurricane strength, it becomes harder to suppress, meaning those that do develop can still cause catastrophic damage.
The picture is different in the Pacific, where El Niño has the opposite effect, causing more and stronger storms.
Marine ecosystems are also under pressure. Warmer ocean temperatures associated with El Niño can cause coral bleaching and increase stress on reefs that are already weakened by repeated heat stress associated with climate change.
Agriculture is also being affected. In India, mango growers have reported a sharp decline in yields after abnormal weather conditions disrupted flower and fruit growth, affecting both supply and income for growers.
How does climate change affect El Nino?
Scientists say that there is no clear evidence that climate change is making El Nino stronger. But climate change could increase its effects.
“Climate change could turn severe El Niño droughts into extreme El Niño droughts,” said Michael McFadden, a senior scientist at the National Oceanic and Atmospheric Administration.
A warmer climate contains more moisture, increasing the risk of excessive rainfall and flooding. Higher temperatures can also exacerbate drought by drying out the soil faster.
Since global temperatures are already near record highs, El Niño events could easily push global temperatures into new record territory.
Can countries prepare?
One advantage of El Niño is that it develops slowly and can be monitored months in advance.
Scientists can monitor ocean temperatures and atmospheric conditions, giving governments and communities time to prepare.
Forecasts can help officials protect crops, strengthen flood defenses and improve early warning systems.
“We know where it will be unusually wet or dry,” McFadden said. “There is plenty of time to develop mitigation strategies to avoid some of the worst impacts through these long-term weather forecasts.”
Edited by: Sarah Stephan