With a 90% chance of the global weather phenomenon striking this year, impacts both devastating and beneficial will be felt from India to Peru

The global El Niño weather phenomenon, whose impacts cause global famines, floods – and even wars – now has a 90% chance of striking this year, according to the latest forecast released to the Guardian.

El Niño begins as a giant pool of warm water swelling in the eastern tropical Pacific Ocean, that sets off a chain reaction of weather events around the world – some devastating and some beneficial.

India is expected to be the first to suffer, with weaker monsoon rains undermining the nation’s fragile food supply, followed by further scorching droughts in Australia and collapsing fisheries off South America. But some regions could benefit, in particular the US, where El Niño is seen as the “great wet hope” whose rains could break the searing drought in the west.

El Niño interactive map What is El Niño

The knock-on effects can have impacts even more widely, from cutting global gold prices to making England’s World Cup footballers sweat a little more.

The latest El Niño prediction comes from the European Centre for Medium-range Weather Forecasts (ECMWF), which is considered one the most reliable of the 15 or so prediction centres around the world. “It is very much odds-on for an event,” said Tim Stockdale, principal scientist at ECMWF, who said 90% of their scenarios now deliver an El Niño. "The amount of warm water in the Pacific is now significant, perhaps the biggest since the 1997-98 event.” That El Niño was the biggest in a century, producing the hottest year on record at the time and major global impacts, including a mass die-off of corals.

“But what is very much unknowable at this stage is whether this year’s El Niño will be a small event, a moderate event – that’s most likely – or a really major event,” said Stockdale, adding the picture will become clearer in the next month or two. “It is which way the winds blow that determines what happens next and there is always a random element to the winds.”

The movement of hot, rain-bringing water to the eastern Pacific ramps up the risk of downpours in the nations flanking that side of the great ocean, while the normally damp western flank dries out. Governments, commodity traders, insurers and aid groups like the Red Cross and World Food Programme all monitor developments closely and water conservation and food stockpiling is already underway in some countries.

Professor Axel Timmermann, an oceanographer at the University of Hawaii, argues that a major El Niño is more likely than not, because of the specific pattern of winds and warm water being seen in the Pacific. “In the past, such alignments have always triggered strong El Niño events,” he said.

El Niño events occur every five years or so and peak in December, but the first, and potentially greatest, human impacts are felt in India. The reliance of its 1 billion-strong population on the monsoon, which usually sweeps up over the southern tip of the sub-continent around 1 June, has led its monitoring to be dubbed “the most important weather forecast in the world”. This year, it is has already got off to a delayed start, with the first week’s rains 40% below average.

Facebook Twitter Pinterest A farmer awaits rain on his drought-hit paddy field in Morigoan, Assam, India. Photograph: Manoj Deka/Corbis

“El Niño could be quite devastating for agriculture and the water supply in India,” said Dr Nick Klingaman, an El Niño expert at the University of Reading in the UK. Two-thirds of Indian farmland lacks irrigation and is reliant solely on rainfall, meaning even current official prediction of a 5% reduction in monsoon rains would have a major impact: a 10% fall is an official drought. Krishna Kumar, an Indian meteorologist and El Niño expert, said that even if the 2014 El Niño turns out not to be a very hot one, it can still have a major effect on the monsoon because it is the specific location of the warm Pacific water which is the critical factor. “The moderate El Niños of 2002 and 2009 impacted the monsoon in India much more greatly then the major 1997 event,” he said, adding that the biggest cut in rainfall is not usually felt until September.

Rana Kapoor, president of the Associated Chambers of Commerce of India, warned: “We recommend the government to immediately announce steps to control food inflation in view of the impending El Niño and the cascading negative affect it will have on crop production.” The impact on farmers means past monsoon failures have cost the nation $20bn (£12bn) in lost output and, because the Indian market dominates global gold prices, the cost of the precious metal has already fallen.

Global sea surface temperature in May 2013 and May 2014. Photograph: NASA

New research in May showed the global impact of El Niño events on food supplies, with corn, rice and wheat yield much lower than normal, although soybean harvests tend to rise. While food production has improved in the last year, El Niño is set to reverse that trend, according to Leo Abruzzese, global forecasting director for the Economist Intelligence Unit. “It may reduce agricultural output over the next few years, which could weigh on global food security”. Drought linked to the 2007 El Niño led to a surge in food prices in 2008 that sparked riots in countries as far afield as Egypt, Cameroon and Haiti.

After India, El Niño’s impacts roll eastwards and officials in Cebu, the Philippines’ second city, have already urged all households to save water to reduce the impact of the drier weather due to hit by the end June. In Malaysia, the national water authority is preparing for a dry spell of up to 18 months and calling for water rationing, while meteorologists have warned of forest fires.

The hot, dry skies will then track to heat-wracked Australia, where 2013 was already its hottest year on record and El Niño is threatening to turn the temperature up even further. Andrew Watkins, manager of climate prediction services at the Australian Bureau of Meteorology, said: “El Niño is one of the largest influences on Australia’s climate. It’s why historically Australia has had one of the most variable climates on the planet.” Watkins said El Niño increases the chances of low rainfall in the country’s southern and most populous half and tends to deliver hotter years and higher extreme temperatures.

Facebook Twitter Pinterest Low water levels at Lake Hume, on the Victoria-NSW border, Australia, during the dry summer of 2007, when the last El Niño occurred. Photograph: Ashley Whitworth/Alamy

Brent Finlay, president of Australia’s National Farmers’ Federation, said he was hoping El Niño just does not happen. “We have farmers and graziers in New South Wales and Queensland who are in drought now, and so to have this prediction of a possible El Niño will be of grave concern.” Severe drought at any time could have “tragic” consequences on rural communities where he said some farmers had even taken their own lives, he said: “That is what drought does.”

However, on the opposite side of the Pacific, in the US, El Niño holds out the prospect of relief for the parched western states and nowhere is more desperate for rain than California. The entire state is in severe or extreme drought, after receiving barely a quarter of its annual rainfall, and communities have been under water rations since March, which ordinarily would still be the rainy season. The result is a tinder box, with governor Jerry Brown warning the state faces the worst wildfire season on record.

A strong El Niño would bring rain, typically double the annual average in southern California. “I commonly refer to El Niño as the great wet hope,” said Bill Patzert, a climate scientist at Nasa’s Jet Propulsion Laboratory in California. “Everyone in the west has their fingers crossed because we are bone dry. We have had three of the four driest years in the west in recorded history. Dry land farmers and ranchers are definitely on their knees right now. We are running on reserves, we are pumping aquifers, and our reservoirs are at record lows.” El Niños also typically lead to wetter winters in Texas, and other parts of the south-west, which also depend on getting most of their rain in the winter months.

Facebook Twitter Pinterest Griffith Observatory stands as clouds gather above the skyline of downtown Los Angeles, California. Photograph: Patrick T. Fallon/Getty Images

However, big El Niños like the 1997-98 event – what Patzert calls “godzillas” – are rare and forecasters at the US government’s climate prediction centre said on 5 June that time was running out for a significant El Niño to be set in train. A modest or small El Niño would have little impact on the drought, said Patzert, noting that the 2006-07 drought – the worst on record at the time – occurred during a weak El Niño year. Even a “godzilla” would not be enough on its own to bail California out, he said: “But it would be a fantastic down payment on drought relief.”

Strong El Niños also typically bring warmer winters to the northern US states, which would be a relief after last winter’s Arctic conditions.

El Niños also typically damp down hurricane activity. But Prof Kerry Emanuel, an atmospheric scientist at MIT, said even in an El Niño year a hurricane, given the right conditions, could still cause tremendous destruction. Hurricane Andrew, one of the deadliest and costliest in recent history, roared through Florida in 1992, which was an El Niño year. “It would be tragic if everyone let their guard down,” Emanuel said.

Elsewhere in the Americas, a careful watch is being kept in Peru, where the huge anchovy fishery has been wiped out by previous El Niños – it was Peruvian sailors who first named the phenomenon “the Christ child” because its peak occurs at Christmas. The 1997-98 El Niño slashed the catch by 80%, as the fish migrated away from the abnormally warm waters. Luis Icochea, a fisheries expert at the National Agrarian University in Lima, warned that the event this year is developing in a similar way.

Rodney Martínez, at Ecuador’s International El Niño Centre, said El Niño would affect the whole of south America, meaning heavy rainfall and floods in Ecuador, Peru, Chile and northern Argentina but potential drought relief in Chile and Bolivia. The early effects of El Niño in Brazil are expected to raise temperatures during the football World Cup.

Facebook Twitter Pinterest Flooded streets in the town of Tuman, Peru. Photograph: Jaime Razuri/AFP/Getty Images

But, despite better El Niño warnings nowadays, Martinez said many nations were worse prepared than in 1997: “In many cases the vulnerability has increased: more exposed population, more land degradation, river sedimentation, collapse of underground water sources, degradation of natural protection in riversides, badly designed infrastructure and lack of coordination and planning to cope with El Niño.”

Stockdale said other global impacts could be droughts in the Caribbean and southern Africa at the end of the year, and also in central Asia, although the precise impacts of each El Niño vary due to local climatic variations. Europe is the continent least affected by El Niño by virtue of being on the opposite side of the world.

However, in the tropics and sub-tropics, another deadly impact of El Niño is becoming better understood: its ability to spark civil wars. Solomon Hsiang, at Columbia University, New York, showed in 2011 that 50 of the 250 conflicts between 1950 and 2004 were triggered by the El Niño cycle, probably due to the loss of crops, jobs and the psychological effects of hotter weather.

Predicting El Nino blindfolded Predicting El Niño blindfolded?

Hsiang told the Guardian that, based on historical data, a Pacific warming of 0.8C is associated with a rise in the annual risk of conflict of 15%. The current forecasts indicate that this year’s warming will most probably lie between 0.5C and 1.5C. “Of course, conflicts may not occur just because the risk of conflict is higher, in the same way car accidents don’t always occur on rainy days when the risk of accident is higher,” Hsiang said. “But it is certainly a developing situation that we should keep track of and it would be excellent to have policy-makers and the public aware of the potential risk.”

Policymakers are likely also to feel the heat of El Niño in the negotiations towards a global deal to cut carbon emissions and tackle global warming, which must culminate in Paris in December 2015. Since the scorching year of 1998, the rate of global warming has slowed, with over 90% of the heat trapped by CO2 going into the oceans.

“A lot of energy that should have been in the atmosphere has gone into the Pacific,” said Kumar. “If El Niño does set in that could trigger the release of that heat and faster warming: that has been a major concern.” An El-Niño-boosted 2015 could well be the hottest year on record, according to Klingaman, just as nations have to agree a climate change deal.

“If 2014 turns out to be an El Niño year as currently forecast, increased public awareness of the dangers of human-induced climate change is likely to follow,” said Prof Michael Raupach, director of the Climate Change Institute at the Australian National University. “However, it is very important that our policy responses do not wax and wane with El Niño.”

The link between global warming and El Niño, a natural climate phenomenon, is not yet well understood by scientists. But a study published in January predicted a doubling of extreme El Niño events, as climate change ramps up.

Either way, adding the impacts of El Niño to the extreme weather already being driven by climate change increases the damage caused, said Stockdale: “El Niño can be the thing that pushes you over the edge. It will be in the years when you get a big El Niño when you feel the impact of climate change the most.”