Nasa reports early signs of El Niño formation that could herald drought in SA

Nasa reports early signs of El Niño formation that could herald drought in SA

 Farmer Ryan Mathews inspects a mealie cob in a drought-affected field in Lichtenburg, North West in 2015. (Photo: Waldo Swiegers / Bloomberg via Getty Images)


By Ed Stoddard


15 May 2023  1

The US space agency Nasa has reported that a satellite monitoring sea levels has spotted Kelvin waves moving eastward along the equator toward the west coast of South America. This is a strong signal that El Niño is forming — and the implications for South African agriculture could be chilling.

Listen to this article

0:00 / 4:39



The return of El Niño this year has been forecast for the past few months. Now, a clear sign of its formation has been detected with satellite imagery.

“The most recent sea level data from the US-European satellite Sentinel-6 Michael Freilich indicates early signs of a developing El Niño across the equatorial Pacific Ocean. The data shows Kelvin waves – which are roughly five to 10 centimetres high at the ocean surface and hundreds of miles wide – moving from west to east along the equator toward the west coast of South America,” Nasa said in a statement.

“When they form at the equator, Kelvin waves bring warm water, which is associated with higher sea levels, from the western Pacific to the eastern Pacific. A series of Kelvin waves starting in spring is a well-known precursor to an El Niño,” Nasa said.

This being Nasa, it’s all very hi-tech.

“Satellites like Sentinel-6 Michael Freilich can detect Kelvin waves with a radar altimeter, which uses microwave signals to measure the height of the ocean’s surface. When an altimeter passes over areas that are warmer than others, the data will show higher sea levels,” Nasa said.

El Niño typically heralds drought in this region. The 2014-2016 event was a scorcher which slammed the grain, livestock, game and other agricultural sectors in South Africa.

Read more in Daily MaverickEl Niño looms, boding ill for SA agriculture and food inflation

The one that is on its way is forming against the backdrop of extreme weather conditions that could make it an absolute blazer.

The US National Oceanic and Atmospheric Administration (Noaa) said on 12 May that April 2023 was the planet’s fourth warmest on record, with things really heating up south of the equator.

“The Southern Hemisphere had its warmest April and warmest month on record. The April 2023 temperature surpassed that of the previous record-warm month — March 2016 — by 0.10 of a degree F (0.06 of a degree C),” Noaa said.

Meanwhile, the oceans are cooking.

“Global ocean temperatures set a record high for April at 1.55°F (0.86 of a degree C) above the long-term average. This marked the second-highest monthly ocean temperature for any month on record, just 0.02 of a degree F (0.01 of a degree C) shy of the record-warm ocean temperatures set in January 2016,” Noaa said.

These records indicate the scale of the climate crisis that has been triggered by the burning of fossil fuels and other human activities.

“We’ll be watching this El Niño like a hawk,” said Josh Willis, Sentinel-6 Michael Freilich project scientist at Nasa’s Jet Propulsion Laboratory in southern California.

“If it’s a big one, the globe will see record warming.”

That is a sobering prospect for South African agriculture and farmers here will also be watching it like a hawk.

An extended La Niña – the opposite of El Niño – drenched much, though not all, of South Africa with stout rainfall in the past three years, and maize and other farmers have reaped bumper crops as a result.

The return of El Niño also looks set to coincide with what economists hope will finally be a cooling of food inflation in South Africa, which hit a 14-year high in March of 14%.

An intense El Niño, combined with the rand’s renewed weakness and the impact on business costs of rotational power cuts, could keep food prices on the boil longer.

El Niño is sure to be high on the agenda at the Nampo Agricultural Trade Show which starts on 16 May in Bothaville in the northern Free State. Many of the farmers in attendance will have bounties in the fields ripe for harvest.

But Kelvin waves in the Pacific may leave next season’s prospects withering on the vine. DM/BM/OBP