Climate Graph of the Week: Will El Niño Return for a Fiery 2023?

Scientists are calculating the chances of the world experiencing record temperatures this year as they assess the likelihood of the return of the El Niño weather phenomenon associated with heat and drought.

El Niño causes the surface of the Pacific Ocean to warm, resulting in changes in temperature and precipitation around the world.

The World Meteorological Organization warned this week that the likelihood of El Niño developing this year is increasing and that its reemergence “would likely fuel higher global temperatures”.

There was “a 60% chance” that El Niño would develop between May and July, rising to 80% between July and September, he predicted.

The US National Oceanic and Atmospheric Administration has also issued a El Niño Watch Alert. in April he concluded there was a 62% chance that El Niño would develop between May and July.

The return of El Niño would be a long-awaited transition from the rare three-year cycle of the corresponding La Niña weather model – the opposite weather phenomenon involving the cooling of the surface temperature of the Pacific Ocean.

This weather system was officially declared over by meteorologists earlier this year after taking its toll with devastating floods in the United States and Australia and catastrophic droughts in Africa and South America.

Below average rainfall in 2021 and 2022 was a factor leading to record drought in the horn of Africaand was partly the result of La Niña’s presence.

“The unusually stubborn La Niña is now over” and neither La Niña nor El Niño were active, the WTO said last week.

However, there has been a “significant increase” in sea surface temperatures in the Pacific Ocean since February, the group said.

Although three years of La Niña acted as a temporary “curb” on global temperatures, the last eight years have been the warmest on record, said Petteri Taalas, WTO secretary general.

“The development of an El Niño will most likely lead to a new peak in global warming and increase the possibility of breaking temperature records,” he said.

A strong El Niño event occurred between 2015 and 2016, with 2016 being the hottest year on record.

If El Niño develops, regions such as South America, the southern United States and the Horn of Africa could experience increased rainfall and potential flooding, while the risk of drought would increase in regions such as Australia and Indonesia.

The Food and Agriculture Organization of the United Nations said in April it was “looking into” risk areas that could suffer from food insecurity during an El Niño period and any “preventive action” that could be taken to mitigate the effects.

Potential FAO actions included liaising with government officials and building seed stockpiles, depending on the severity of the situation.

Brazil and South Africa were among the grain-producing countries at risk of abnormally dry conditions and potential crop failures during an El Niño year, for example, the group said.

For an El Niño event to be declared, the equatorial temperatures of the Pacific Ocean must exceed a certain threshold, while changes in the atmosphere, such as winds at the equator, must also be detected.

The onset of El Niño was ‘harder to predict much in advance’, said the EU’s Copernicus climate change service. Predicting what might happen is especially challenging early in the year during the transition from La Nina to neutral or El Niño.

On Friday, the World Weather Attribution team of scientists concluded that climate change made this year’s April record-breaking heatwave in Spain, Portugal, Morocco and Algeria “at least 100 times more likely.”

The heat levels recorded “would have been nearly impossible” without human-led warming, he said. Temperatures have already risen by at least 1.1°C in the industrial age.