Climate scientists have warned of wild weather in the year ahead as the start of the global “El Niño” phenomenon exacerbates the impact of global warming. As well as droughts, floods and other extreme events, the next few years are also likely to be the hottest on record, scientists say.

In the UK, a Met Office spokesman said yesterday that the El Niño event was likely to cause a hot, dry summer following a warm June, but said it could have other unpredictable effects on weather in Britain and north-west Europe. “Much depends on how much the El Niño deepens in the next few months.”

El Niño – “the child” in Spanish – was named by fishermen in Peru and Ecuador because the phenomenon arrives there at Christmas. It is part of a natural meteorological cycle that happens every 3-7 years and affects weather worldwide for a year or more. It is caused by changes in ocean temperatures, with the first sign being abnormal warming in the Pacific.

Sea surface temperatures across an area of the Pacific almost the size of Europe have been increasing for six months and will trigger worldwide weather turbulence for the next year, said a spokesman for the US National Oceanic and Atmospheric Administration (Noaa).

At this stage, both US and Australian climate scientists say this may be a medium-strength El Niño, but they have warned it could develop further.

“Temperatures in the Pacific are around 1C above average, and sub-surface temperatures up to 4C warmer than normal, ” said a spokesman for Australia’s Bureau of Meteorology.

The last major El Niño in 1998 killed more than 2,000 people and caused billions of dollars worth of damage to crops and infrastructure in Australia and Asia. It led to forest fires in south-east Asia, a collapse of fish stocks in South America and a drought threatening 700,000 people in Papua New Guinea.

Strong El Niños often have long-lasting effects. The 1991-92 event led to droughts in Africa and food shortages that left 30 million people at risk of malnutrition and set back development for a decade.

Oxfam has alerted teams globally. “This could be the hottest year in known history. Poverty and climate change is enough of a challenge: an El Niño will only make things harder,” said Steve Jennings, Oxfam’s disaster risk reduction manager.