In the 1600s, fishers in Peru saw that every few years around Christmastime, the waters there warmed, and they caught fewer anchovies. They called this ���El Ni単o��� ��� the boy ��� after the Christ child.

In the early 20th century, the physicist Gilbert Walker noticed that the prevailing low atmospheric pressure and rainy weather over the western Pacific and dry, high pressure over the eastern Pacific periodically flipped. But it wasn���t until 1969 that meteorologist Jacob Bjerknes linked the two, showing that swells of warm water in the Pacific Ocean end up wreaking havoc on weather across the globe.

Under normal conditions, the sun���s heat and Earth���s spin fuel east-to-west trade winds around the tropics, which blow water into a ���warm pool��� near Indonesia. As this warm pool grows, it builds up energy. ���It could be a bit like a coiled spring waiting to emerge,��� says at the University of Reading, UK.

Every two to seven years, natural chaotic disturbances release that spring. Bursts of westerly winds can blow against and slow the easterly trade winds, allowing swells of warm water to across the Pacific Ocean, raising sea levels along the coasts of Peru, Colombia and Ecuador. These so-called Kelvin waves indicate that El Ni単o is coming.

A self-reinforcing cycle called the kicks in. The blob of warm water suppresses the upwelling of cold, nutrient-rich deep water that normally makes Peru���s anchovy fishery so rich, further warming the surface water. The warm sea heats the air above it and causes it to expand. The resulting fall in atmospheric pressure slows the trade winds down even more, since winds flow from high to low pressure. This allows still more warm water to slosh back into the eastern Pacific.

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The swathe of warm water stretching across the tropical Pacific releases trillions of joules of heat energy into the atmosphere, raising worldwide temperatures on top of global warming. This is why scientists expect 2027 to be the hottest year on record. But it also drastically alters weather patterns, bringing drought and wildfires to some areas and storms and flooding to others.

Normally, warm air rises over the warm pool, carrying moisture that falls out in thunderstorms, which is why rainforests flourish in places like Indonesia. Denuded of moisture, this warm, dry air then reaches the top of the troposphere and spreads out to the east and west. It descends over the eastern Pacific and the Horn of Africa, fuelling a belt of such air loops around the tropics called the Walker circulation.

During El Ni単o, however, the warming of the eastern Pacific moves this upward convection eastward, shifting the entire Walker circulation. Now dry, warm air that was sinking over the Horn of Africa and the eastern Pacific is sinking over Indonesia and the Amazon, encouraging drought and wildfires there. Over eastern Africa, warm air is rising, increasing rainfall and the risk of flooding.

Meanwhile, the warming waters also create a stronger temperature contrast between the tropical and northern Pacific, strengthening the jet stream and bringing more storms and wet weather to the southern US. It can bring storms and rain to the UK as well, in certain circumstances.

���If this deep convection in the atmosphere moves around, it changes things locally, but it also then starts to change the whole circulation of the atmosphere,��� says at the European Centre for Medium-Range Weather Forecasts. ���That���s why El Ni単o is a big deal, not just some local process.���

A record El Ni単o climate phase will unleash unprecedented heat and extreme weather, and the UK food system is vulnerable, climate minister Katie White told New Scientist.

At the same time, she pushed back against ���panic and fear��� after environment minister Angela Eagle told Britons they should ���store a bit of food that can keep you going for a while��� in case of El Ni単o storms and flooding.

���Look, am I going out and buying loads of extra beans? I���ve always got a few cans of beans, but that���s mainly so I���m ready for when I���ve not had a chance to go to the shop,��� said White. ���So I���m not going out and doing that.���

The UK Met Office, the national weather service, has that the UK is likely to face an unusually warm, wet and stormy autumn and winter due to El Ni単o, which occurs every two to seven years. While late winter in the UK has often been cold and dry during El Ni単o, the current event is so strong that it could remain warm and rainy into spring.

If fields become too muddy, tractors may not be able to sow crops like winter wheat, as happened in the 2023-24 El Ni単o, or the plants could fail to sprout. Continued wet weather could undermine spring barley. Farmers could be forced to spend more on livestock feed and housing, raising meat and dairy prices as well.

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Closer to the tropics, crops like rice could fail due to heat, drought and weakened monsoons. A UK government last week warned that El Ni単o could increase UK prices for imported foods such as rice, cocoa and coffee.��This comes after heatwaves and drought linked to global warming reduced crop yields in the northern hemisphere this summer, resulting in the worst-ever wheat, barley, rape and oat harvest in the UK. ��

���We will have a wetter start to this winter��� On the back of a very dry summer, that is difficult,��� said White. ���The food system is vulnerable.���

Large countries including China, Brazil and Germany have been building up stores of key foods like wheat, rice, corn and sugar. But the UK doesn���t keep substantial public food reserves.

White argued that the UK would be better off helping local farms and groceries to become more resilient to climate shocks. A task force she established that includes military experts and scientists will meet in October to scrutinise readiness for climate security threats, including to food.

���I don���t think we need to be in a position of grain stores, but I do think we do need to be looking at where the vulnerabilities are in the food system and how we support local production in the most sustainable way,��� she said. ���That���s going to be working with farmers and also on local supply chains.���

Farmers will probably have to plant more weather-resistant varieties or different crops entirely, according to at the University of Oxford. The UK also needs to reduce its reliance on imports for 40 per cent of its food. But ���grain storage is definitely part of the answer��� as well, she says.

El Ni単o flooding could also threaten housing and infrastructure, and these risks will continue as climate change makes most of the world warmer and wetter. The UK should not only build anti-flood engineering works such as the Thames Barrier, but also restore ecosystems like wetlands to absorb excess water, said White. Extreme heat, which killed at least 35,000 people in Europe this year, is likely to bake the continent again next summer.

The long-term solution is for the UK and other countries to reach net-zero greenhouse gas emissions by 2050, she said, a goal that right-wing parties have been increasingly attacking in the UK, the European Union and the US.

Yet the Department for Energy Security and Net Zero, which White is a part of, is reportedly set to the Jackdaw gas field off Scotland, and may consent to the Rosebank oil field as well. These would result in at least 275 million tonnes of carbon dioxide emissions over their lifetime, equivalent to about three-quarters of the UK���s current annual greenhouse gas emissions.

White said she couldn���t comment as the approvals are up to energy secretary Miatta Fahnbulleh, but noted that ���oil and gas is part of our mix going forward���.

She argued that the growth of renewable energy, which now generates more than half of UK electricity, would reduce fossil fuel emissions over time, pointing out that the UK has almost as many public electric vehicle chargers as petrol pumps. Her department also just 贈30 million of funding for 1000 community-owned solar, hydro and wind projects.

This month, the UN the world will soon fail the goal of limiting global warming to 1.5属C above pre-industrial levels and will have to rely on CO2 removal ��� ranging from tree planting to carbon-sucking machines ��� to bring temperatures back down in the future. The UK���s Advanced Research and Invention Agency is funding 贈57 million of research into geoengineering techniques like spreading sun-blocking particles in the atmosphere.

White said the UK has no plans to deploy geoengineering and she is concentrating on reducing climate impacts in the near term.

���My focus as climate minister is��� adaptation and resilience because I know that next summer is likely to be very, very hot,��� she said. ���But also for this winter, how do we accelerate electrification? Because that is the best way to bring people���s bills down.���