The El Niño weather phenomenon is 'supersizing before our eyes' as it threatens to wreak havoc on the UK in autumn and early winter, experts have warned.
Scientists from the World Meteorological Organization (WMO) said the climate pattern – where Pacific sea surface temperatures become significantly warmer than average – is now 'firmly established' and is set to have huge impacts on rainfall and temperatures globally, triggering floods, drought and extreme heat.
Forecasts indicate an 'exceptionally huge likelihood of nearly 100 per cent' that El Niño will cause problems until February – the first time such an unequivocal update has been issued.
In the UK, El Niño is likely to make autumn and early winter colder, wetter and stormier, according to the Met Office.
UN Secretary-General Antonio Guterres said: 'El Niño is being supersized before our eyes. The science leaves no room for doubt: the planet is in uncharted waters – and those waters are heating up.
'Sea surface temperatures are rising, temperatures keep climbing and the world is in the danger zone of extreme weather.
'The race now is between rising risks and our commitment to take climate action and protect people. We must win that race.'
Scientists warned El Niño is 'firmly established' and 'being supersized before our eyes' as temperatures continue to rise
Experts said the phenomenon will have huge impacts on rainfall (pictured) and temperatures across the globe
The El Niño Southern Oscillation is a naturally occurring climate cycle that shifts between hot El Niño years and cool La Niña years once every two to seven years.
As we enter an El Niño phase, the powerful trade winds that normally blow hot water across the Pacific towards Australia weaken, or even reverse.
That prevents cool waters welling up from the deep ocean below and causes hot water to collect near the surface off the west coast of South America.
Eventually, that warm water starts to spread out, raising the average global temperature and causing major disruptions to weather patterns around the globe.
The WMO said sea surface temperatures in the region at the heart of El Niño are already well above average and are continuing to rise.
The developing El Niño has gathered pace dramatically in recent months, with Pacific Ocean temperatures now more than 2C above average in some regions.
Scientists say the warmth lurking beneath the surface is even more remarkable, with some underwater areas reaching a staggering 8C above normal.
For September to November this year, the WMO's forecasts indicate there will be above-normal temperatures across almost all land areas around the world.
Forecasts indicate an 'exceptionally huge likelihood of nearly 100 per cent' that El Niño will wreak havoc until February
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El Niño generally begins developing between March and June and reaches its peak intensity between November and February.
Its impact on global temperatures can extend beyond the period of peak ocean warming and be most pronounced in the year after development.
'El Niño has the potential to deliver a massive blow to communities and economies across the world,' WMO Secretary-General Celeste Saulo said.
'We are already seeing disruption and devastation from droughts and floods and we expect these impacts to increase as El Niño intensifies.'
Britons have been told to brace for a cold and stormy winter as warm ocean temperatures in the Pacific send 'waves' rippling through the atmosphere.
These waves push the world's most powerful weather systems – including the jet stream – off their usual course, wreaking havoc on Britain's winter weather.
This winter, experts predict the jet stream will send storms towards the UK along powerful currents of fast-moving winds.
While it is still too early to say when these storms will occur, the latest weather predictions agree that bad weather is increasingly likely.
The developing El Niño has gathered pace dramatically in recent months, with Pacific Ocean temperatures now more than 2°C above average in some regions
Will Lang, chief meteorologist at the Met Office, told the Daily Mail: 'El Niño conditions increase the chance of storms in late autumn and early winter.'
Professor Bill McGuire, Professor Emeritus of Geophysical Hazards, said: 'Powerful El Niños typically bring mild, stormy Autumns and early Winters to the UK, followed by bitter cold, although this isn't set in stone.'
A separate study, published last week, found the El Niño events have been ramping up for decades.
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Scientists from the University of Michigan examined corals in the Galapagos Islands to estimate the strength of previous events.
Their analysis revealed that El Niños have become nearly 40 per cent stronger in the last 40 years than the previous 1,000.
'We don't see a time in the past where El Niños have been as strong as today,' said lead author Professor Julia Cole.
'We show that the strength of El Niño changes in parallel with the warming of global temperature.
'Our findings tell us that the big El Niño events of the last 40 years are not normal in the context of the last thousand years.'
WHAT IS THE EL NINO PHENOMENON IN THE PACIFIC OCEAN?
El Niño and La Niña are the warm and cool phases (respectively) of a recurring climate phenomenon across the tropical Pacific - the El Niño-Southern Oscillation, or ENSO for short.
These changes disrupt air movement and affect global climate.
- : A warming of the ocean surface, or above-average sea surface temperatures (SST), in the central and eastern tropical Pacific Ocean. Over Indonesia, rainfall becomes reduced, while rainfall increases over the tropical Pacific Ocean. The low-level surface winds, which normally blow from east to west along the Equator, instead weaken or, in some cases, start blowing the other direction from west to east.
- : A cooling of the ocean surface, or below-average SST, in the central and eastern tropical Pacific Ocean. Over Indonesia, rainfall tends to increase, while rainfall decreases over the central tropical Pacific Ocean. The normal easterly winds along the Equator become even stronger.
- : Neither El Niño or La Niña. Often tropical Pacific SSTs are generally close to average.
Source: Climate.gov