London: At least 10 million of the world’s poorest people are set to go hungry this year because of failing crops caused by one of the strongest El Nino climatic events on record, Oxfam has warned.

The charity said several countries were already facing a “major emergency”, such as Ethiopia, where 4.5 million are in need of food aid because of a prolonged scarcity of rain this year.

Floods, followed by drought, have slashed Malawi’s maize production by more than a quarter, farmers in central America have suffered from two years of drought and El Nino conditions have already reduced the Asian monsoon over India, potentially triggering a wider drought across the east of the continent.

Indonesia’s government has declared drought in 34 of the country’s provinces because of El Nino, while two million people in Papua New Guinea have been affected by crops shrivelling in heat in some parts of the country and severe frosts in its highlands.

El Nino is a periodic climatic phenomenon where waters of the eastern tropical Pacific warm, triggering a range of potential consequences for global weather. While parts of South America are typically doused in heavy rainfall, warmer, drought-like conditions are experienced in Australia, south-east Asia and southern Africa.

The UK Met Office has predicted this year’s El Nino could be the strongest on record since 1950, warning that famine could grip west Africa.

An Oxfam report, called Entering Uncharted Waters, states the El Nino will rival that of 1998, which caused droughts, floods and forest fires that resulted in 2,000 deaths and caused about $33 billion (Dh120 billion) in property damage.

The report warns “major humanitarian emergencies” were possible without proper intervention, pointing out that failure to respond to drought has proved disastrous in recent years, such as 2011 when rains failed in the Horn of Africa and more than 260,000 people died.

Dr Helen Szoke, the chief executive of Oxfam Australia, said the charity had already started work with communities, including in Papua New Guinea, in an attempt to stave off crop failures.

“We are working with farmers in PNG to plant drought-resistant seeds and to help them with the collection of rainwater,” she said. “Vanuatu is another country where we are doing that work although, cruelly, they’ve already had a head start due to the repairing of water systems due to cyclone Pam.

“Our staff in Zimbabwe and Malawi, for example, are expressing concern about the preparedness of the seasonal crop. People who rely on subsistence farming aren’t necessarily prepared for frosts or drought, which is when food security becomes an issue.

“The poorer countries don’t have the systems in place and are much more vulnerable. Potentially millions of people will be affected by a lack of access to water and if food prices go up, the poor will miss out again.” El Nino-like conditions were expected last year but failed to materialise. The El Nino now brewing in the Pacific Ocean is expected to end in January but may, in the long term, become more frequent. Research published in Nature Climate Change last year predicted El Nino frequency could double because of climate change fuelled by the release of greenhouse gases.

Last year was the warmest year globally on record, with 2015 and 2016 potentially set to cause this record to topple again.

Szoke said the international community needed to ensure El Nino conditions weren’t replicated every year by changes to rainfall, extreme heat and cyclones caused by climate change.

“We can’t keep just patching up communities,” she said. “We need a long-term vision for climate change. We need to reduce emissions, move away from old technologies and address this issue. We have an opportunity to do that in Paris [at UN climate talks] later this year.”

What is El Nino?

El Nino is an ocean and atmospheric phenomenon that has a significant impact on our planet’s weather.

While an El Nino event influences the whole world, the main effect is on the Pacific area, especially Australia, Indonesia and south-west America.

“During El Nino we have the droughts in western Pacific countries, like Indonesia and Australia,” says Dr Wenju Cai, a senior principal research scientist at CSIRO Wealth from Oceans Flagship. “But in other places — like Ecuador and Peru — these normally dry areas suddenly get a lot of rain. In the US, in California they experience flooding during El Nino events.”



El Nino and temperatures

El Nino also results in a hotter average temperature for the whole planet by about 0.1 to 0.2 degrees, because the associated change in winds lead to the release of heat from the ocean to the atmosphere.

The two strongest El Ninos that we know of were in 1982-83 and 1997-98. Dubbed ‘super El Ninos’, both these events had significant global impacts.

“In 1982-83, Australia suffered one of the biggest droughts and we had the Ash Wednesday bushfires and Melbourne was covered by the dust storm,” says Cai.

“In 1997, over 23,000 people were killed due to extreme events, droughts, floods, cyclones.”



What led to El Nino research?

The 1982 El Nino caught countries around the Pacific completely unaware and prompted data gathering and research that lead to our current understanding of El Nino, says Cai.



What causes an El Nino?

Typically, an El Nino develops around May/June, strengthens through September/October and November to peak over December/January, then starts to decay in late February with weather conditions returning to normal around March.

The shift from normal — or neutral — conditions to an El Nino (or its opposite — La Nina) is governed by a complex combination of atmospheric and oceanic events.



Normal conditions

In normal conditions, an easterly trade wind blows from the Americas across the Pacific Ocean storing heat in the western Pacific. This sets up a temperature gradient — or thermocline — across the ocean with the eastern Pacific significantly colder than the western Pacific. It also creates what we consider to be normal climatic conditions — a rain band in the western Pacific, bringing rainfall to eastern Australia.

During an El Nino the temperature gradient is reduced, and the water in the eastern Pacific is warmer than normal.



Are scientists divided?

What causes an El Nino to start “is the subject of debate,” says Cai. “One of the scenarios is that a little bit of weakening in the easterly wind would make the warm water flow to the east, and once it flows to the east then the temperature gradient across the Pacific changes.”

The wind may return to a normal pattern, but the ocean has a longer memory and is slower to recover. And before the ocean recovers, another weather event may occur that changes the wind again.

“An accumulation of a number of such events would then lead to a mean westerly wind developing, weakening the temperature gradient, in turn generating bigger westerly winds and a positive feedback,” says Cai.



Are there other factors?

There are numerous other complex factors which come into play as well. For example, a westerly wind will suppress the Humboldt current, which runs up the west coast of Peru and Chile and normally brings an upwelling of cold water from the ocean’s sub-surface to the surface.

Around this stage a tipping point is reached and the interplay between the oceans and atmosphere shifts into a different prevailing pattern, and an El Nino has formed.



What’s happening now?

At the moment we’re seeing the development of westerly wind and warmer temperatures in the equatorial western pacific and so that’s why scientists are predicting an El Nino,” says Cai.



Frequency and severity

Scientists now have a very good idea of how El Nino will be affected by climate change, says Cai, and it’s not looking great.

“Under climate change the frequency of extreme El Nino events will double — to one every ten years”.

The reason behind this is that the eastern equatorial Pacific Ocean — which is normally cooler than the west — is warming exceptionally fast, making it more likely that El Ninos will develop.

— Compiled from agencies