Met Office experts have warned the UK is set to experience more storms and rain over upcoming autumn and winter seasons caused by an “unprecedented” El Nino weather event. El Nino is declared when sea temperatures in the tropical eastern Pacific rise 0.5C above the long-term average, impacting global rainfall patterns and average temperatures.
The natural warming of sea temperatures is forecast to reach more than 3C in the coming months, making this year’s weather event “the largest since the 19th century”, according to the Met Office. It creates a heightened risk of drought in the tropics, southern Africa and north-east Australia, while north-western Europe – including the UK – is likely to experience wetter and stormier conditions in the coming autumn and early winter, the forecaster said.
‘Unprecedented’ El Nino signal
“We should be clear that this is an unprecedented event”, Professor Adam Scaife, head of long range forecasting at the Met Office, said. “I have never seen an El Nino signal this intense in our forecasts.”
He added: “A typical El Nino leads to an equatorial Pacific sea-surface temperature rise of between one to 2C, with 2C being a really big event. This implies that if the forecast is accurate – and other forecast systems show similar extreme values – then 2026 will far exceed our recent experience of El Nino and its worldwide climate influences.”
El Nino events also drive an increase in global average temperature, with 2027 forecast to be the warmest year on record. “During large El Nino events significantly more heat is released from the ocean to the atmosphere leading to an increase in global average temperature, particularly in the calendar year following the winter peak of the El Nino,” Met Office Science Fellow, Dr Nick Dunstone said. “Hence, 2027 is very likely to replace 2024 as the warmest year on record and be another year to temporarily exceed plus 1.5C above the pre-industrial period.”
Climate change and drought context
Professor Stephen Belcher, the Met Office’s chief of science and technology, said: “This summer we have experienced heat waves across Europe reminding us of the effects of climate change, this large El Nino is a reminder that natural variations in the climate system are also at play, adding to the stresses of climate change.”
The unprecedented string of heatwaves and lack of rainfall in recent months has brought the driest July in 190 years and has pushed almost three-quarters (71.3%) of England and all of Wales into drought, putting severe pressure on the water system, wildlife, farmers, emergency services and infrastructure. Many areas of the country are facing water shortages as reservoir levels have fallen to 62.6% – 16.3% lower than is expected for this time of year, according to Defra.
Following an emergency meeting to discuss the heatwave last week, Prime Minister Andy Burnham warned: “We might be in for a wet autumn and winter straight after this, because of El Nino and some of the issues there, which was reported to Cobra.”
Recent rainfall and drought outlook
Parts of the country were hit by heavier showers on Wednesday and Thursday, with the north-west of England seeing the wettest conditions in the last 24 hours, with 52.5mm of rain falling over the seaside town of Morecambe in Lancashire, according to the Environment Agency (EA). This represents a third of the region’s rainfall totals recorded over the period between June 1 and August 18 this year, which reached up to 156mm on average, the Met Office said. Significant showers also broke over southern parts of the country, with Pevensey Bay in East Sussex recording 32mm of rain over the last 24 hours, again according to an EA gauge.
The sudden heavy rainfall this week also sparked fears of flash flooding as the water has been hitting parched, dry, hard ground. But forecasters and officials warned it could take months of sustained rainfall before rivers, reservoirs and groundwaters are completely replenished – which is when a drought is officially over.
The National Drought Group, which brings together the Met Office, regulators, government, water companies, farmers, scientists and conservation organisations several times a year, said this week’s rainfall and cooler temperatures will not make any significant impact on current water scarcity. It also warned drought conditions could persist into the new year as, despite El Nino, current forecasts do not suggest this autumn will have the amount of rainfall required to drive recovery before December.
