A so-called “Godzilla El Nino” could bring chaos including floods, drought and wildfires to large parts of the world this winter, according to weather experts.
The potentially record-breaking phenomenon would disrupt global weather patterns with possible consequences including a freezing winter in Britain, devastating storms in the United States, mudslides in South America, parched conditions in south Asia, and raging wildfires in Australia.
An El Nino occurs every two to seven years and Nasa is closely monitoring water temperatures in the eastern Pacific Ocean, which is a key indicator.
Sea surface temperatures off Peru are already 3.4F (-15C) above average and have been rising for months.
Trade winds from east to west that usually cool the water and push it towards Australia are weakening.
That affects the jet stream and means storms are pushed to the east. El Nino tends to lead to colder than average winters in northern Europe.
A previous El Nino was partly blamed for the severe UK winter of 2009 to 2010, the coldest for decades, which brought parts of Britain to a standstill, causing disruption to transport and sports events, school closures, and power outages.
Experts said El Nino was one of the factors which contributed to the so-called “Big Freeze” but there were others.
The US National Weather Service’s Climate Prediction Centre, which has unofficially nicknamed the brewing El Nino “Bruce Lee”, said it was expected to peak in the late fall or early winter.
Water temperatures in the eastern Pacific are already higher than at the same stage during 1997, when the most powerful El Nino yet recorded struck.
That led to the deaths of an estimated 23,000 people around the world and caused $45 billion (£28.7 billion) in damage.