The El Nino weather phenomenon, predicted to be one of the strongest on record, has been forecast to increase temperatures in many world regions – but in the Gulf its main effect could be to cause more rainfall.
Larger amounts of precipitation may arrive in October and November, and from March to May, including severe bouts that could raise the risk of flooding, although this is not guaranteed.
Extreme weather conditions are expected to last into 2027, according to the World Meteorological Organisation. The UN weather agency forecasted that a near 100 per cent chance exists that El Nino will persist until February, fuelled by exceptionally warm Pacific Ocean temperatures.
“El Nino generally tilts the Gulf and parts of the Arabian Peninsula towards wetter conditions, enhanced moisture transport and a greater chance of heavy rain episodes,” said Dr Diana Francis, associate professor and head of the Environmental and Geophysical Sciences (Engeos) Laboratory at Khalifa University in Abu Dhabi.
If rainfall levels increase, “very intense downpours may become more likely, according to Dr Andries-Jan de Vries, of the Institute of Earth Surface Dynamics at the University of Lausanne in Switzerland.
“In combination with dry soils, with mountains and valleys, they can easily accumulate rainwater that can fall in a very short period of time, and that can then lead to flooding,” he said.
Their comments came after the UAE's National Centre of Meteorology released a statement on Friday saying the country is expected to escape the worst of the weather from the El Nino phenomenon, although the country could experience more rain.
Parts of the UAE were hit by severe flooding in late March this year, almost two years after the country experienced its most extreme rainfall on record, late into what was described as the fifth-strongest El Nino on record.
A study in Nature Scientific Reports in June with the title “An extreme rainfall event over the United Arab Emirates in April 2024: Role of dynamic and thermodynamic drivers”, said that El Nino “may have contributed to a large-scale background environment favourable for above-normal April rainfall over the region”.
After the 2024 floods, the authorities began investing heavily to improve drainage and make the country better able to cope with severe rains.
Heavy rain
The El Nino-Southern Oscillation, to use its full name, is a natural phenomenon in which the upwelling of water causes warmer sea-surface temperatures in the central and eastern tropical Pacific Ocean, with knock-on effects on the global climate. An opposite phenomenon, La Nina, is linked to cooler temperatures in that part of the Pacific Ocean.
According to the US National Oceanic and Atmospheric Administration, El Nino and La Nina each last between nine months and a year and happen irregularly, typically every two to seven years.
El Nino is seen slightly more often, and the one occurring this year and into next year has been forecast to be exceptionally strong.
The World Meteorological Organisation recently said there were “exceptionally warm tropical Pacific Ocean conditions” and warned that a very strong El Nino could “significantly shift rainfall and temperature patterns worldwide and fuel extreme weather”.
A recent study in Weather and Climate Dynamics called “The influence of El Nino-Southern Oscillation on cool-season precipitation variability in the arid Middle East”, highlighted three mechanisms that cause El Nino to influence weather in the Gulf region.
Firstly, El Nino’s warmer sea-surface temperatures in the central Pacific are typically associated with colder sea-surface temperatures and reduced tropical convection around Indonesia and the West Pacific.
“That influences the regional circulation over South Asia and the Indian Ocean, and we have a change in the transport of moisture in the atmosphere,” said Dr De Vries, the first author of the paper.
This results in an increase in moisture coming into the region.
Feeling the pressure
A second pathway is an alternating pattern of high and low-pressure systems running eastward from the warmer region in the Pacific, stretching over North America, the North Atlantic and Europe to the Middle East. This goes along with a low-pressure system over the Middle East, which is more favourable for precipitation.
A third cause is that during El Nino conditions, the subtropical jet stream over North Africa and the Middle East – a band of fast-flowing air blowing from west to east about 12km to 14km above the Earth’s surface – is shifted slightly south, towards the equator. This allows mid-latitude storms to more easily enter the Middle East region.
While El Nino makes wetter conditions in the Gulf region more likely, it does not make them certain.
“El Niño increases the likelihood of wetter conditions but does not guarantee them. Rainfall in the region varies greatly from one year to another,” said Dr Zouhair Lachkar, a senior research scientist in New York University Abu Dhabi’s Mubadala Arabian Centre for Climate and Environmental Sciences, said El Nino was not always linked to higher rainfall.
So while a stronger-than-normal El Nino is statistically more likely to have a greater effect on rainfall than an average one, it may not have a major impact. Effects on rainfall are most likely this October and November, and in March, April and May next year.
Even though El Nino warms the climate globally, Dr Francis said its impacts on UAE and Gulf temperatures were “relatively weak”.
“Background climate warming, Gulf/Arabian Sea temperatures and regional circulation will be at least as important,” she said. “The impact of El Nino in the Gulf happens a few months after it is established in the Pacific. Most probably its impacts will be felt here from mid-autumn onward, and in those seasons it is mainly the rainfall patterns that will be influenced, less the temperature.”
Dr Lachkar said that research at NYU Abu Dhabi showed that El Nino does not necessarily produce higher sea-surface temperatures in the Arabian Gulf. “In fact, we found that La Nina has historically been more favourable to exceptionally high summer sea-surface temperatures in the Gulf,” he said.
Should there be increased rainfall in the UAE, the impact on the natural environment could be positive.
Planting the issue
Prof John Burt, director of NYU Abu Dhabi’s Mubadala Arabian Centre for Climate and Environmental Sciences, said if El Nino brought more winter rain, it could lead to “a marked increase in plant growth across our deserts and mountains”.
“Sufficient rain during the cooler months can trigger widespread germination of seeds, plus flowering and renewed growth in established shrubs,” he said.
"These responses extend through the food web: vegetation provides food for herbivores, flowers support pollinating insects, and greater insect abundance benefits birds, reptiles and small mammals. A productive winter can also replenish seed reserves, supporting future plant generations after the visible greenery disappears.”
He said that while a wetter winter could promote natural regeneration, lasting benefits would depend on the intensity of the initial rainfall events and the subsequent weather.
“Rain that initiates germination must be followed by conditions that allow seedlings to survive, such as continued soil moisture in the weeks and months that follow,” he said. “In contrast, brief but intense downpours can erode soils and uproot vegetation, particularly in mountain wadis and the gravel plains at the foothills.”
He said it is not known if summer temperatures next year will be higher than normal, but that the centre will monitor this closely. “Marine organisms already live very close to their upper heat limits in summer, and are vulnerable to being pushed over the edge,” he said.
