Fears of big freeze as scientists detect slower Gulf Stream

A A A

The ocean "engine" that helps to drive the warm waters of the Gulf Stream and keeps Britain relatively mild in winter has begun to slow down, say scientists.

Measurements of ocean currents in the North Atlantic reveal that they have weakened by about 30 per cent since 1992. The findings, published in the journal Nature, fit computer predictions of what would happen when Greenland glaciers begin to melt because of global warming. The models suggest that extra freshwater released into the North Atlantic could weaken ocean currents and even shut down the Gulf Stream.

Britain benefits from the enormous amounts of heat - equivalent to the output of a million power stations - carried from the Caribbean by the Gulf Stream and the North Atlantic Drift, and a tailing off in these currents could have a major impact on the country's climate.

Scientists estimate that the detected 30 per cent weakening of the Atlantic currents could lead to a fall of about 1C in Britain's average temperatures over the next 20 years.

They also warn that the weakening could be the first signs of an accelerating trend that could eventually lead to a more drastic change, including a complete shutdown of the currents. If this were to happen, average temperatures in Britain could fall by between 4C and 6C, leading to winter temperatures similar to Newfoundland in Canada, which is on the same latitude as the UK but does not benefit from the Gulf Stream.

Professor Harry Bryden, of the National Oceanography Centre at the University of Southampton, said the ocean currents of the North Atlantic acted as a conveyor belt that carried warm water at the surface in one direction and transported cold, deep-water currents in the other.

"It is a massive system that includes the Gulf Stream and it carries heat northward out of the tropics into the northern Atlantic, warming the atmosphere and helping to provide northern Europe with a moderate climate," Professor Bryden said.

For the past 50 years, oceanographers have measured the strength of these currents along a stretch of the North Atlantic situated at a latitude of 25 degrees north of the equator, from Florida in the west to the African coast in the east.

When they analysed that rate of ocean flow - measured in Sverdrups (Sv), or a million tons of water flowing per second - they found that in 1992 it was about 20Sv, but in 2004 it had fallen to 14Sv. "In previous studies over the past 50 years, the overturning circulation and heat transport across 25 degrees north were reasonably constant. We were surprised that the circulation in 2004 was so different from previous estimates," Professor Bryden said.

The study used data from an array of instruments anchored at 22 moorings, nine of which are positioned east of the Bahamas, four in the mid-Atlantic and nine across the continental slope of east Africa. Each mooring is anchored to the seabed on wires 5,000 metres (16,400ft) long, and holds instruments that continuously record salinity, temperature, pressure and current flow. Stuart Cunningham of the National Oceanography Centre said: "Continuous monitoring could alert us to potential rapid climate change."

Have you tried new the Independent Digital Edition apps?
  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
iJobs Job Widget
iJobs General

Recruitment Genius: Project Implementation Executive

£18000 - £23000 per annum: Recruitment Genius: They work with major vehicle ma...

Recruitment Genius: Chiropractic Assistant

£16500 per annum: Recruitment Genius: A Chiropractic Assistant is needed in a ...

Recruitment Genius: Digital Account Executive - Midlands

£18000 - £26000 per annum: Recruitment Genius: They work with major vehicle ma...

Recruitment Genius: Web Developer

£28000 - £30000 per annum: Recruitment Genius: This company provides coaching ...

Day In a Page

NHS struggling to monitor the safety and efficacy of its services outsourced to private providers

Who's monitoring the outsourced NHS services?

A report finds that private firms are not being properly assessed for their quality of care
Zac Goldsmith: 'I'll trigger a by-election over Heathrow'

Zac Goldsmith: 'I'll trigger a by-election over Heathrow'

The Tory MP said he did not want to stand again unless his party's manifesto ruled out a third runway. But he's doing so. Watch this space
How do Greek voters feel about Syriza's backtracking on its anti-austerity pledge?

How do Greeks feel about Syriza?

Five voters from different backgrounds tell us what they expect from Syriza's charismatic leader Alexis Tsipras
From Iraq to Libya and Syria: The wars that come back to haunt us

The wars that come back to haunt us

David Cameron should not escape blame for his role in conflicts that are still raging, argues Patrick Cockburn
Sam Baker and Lauren Laverne: Too busy to surf? Head to The Pool

Too busy to surf? Head to The Pool

A new website is trying to declutter the internet to help busy women. Holly Williams meets the founders
Heston Blumenthal to cook up a spice odyssey for British astronaut manning the International Space Station

UK's Major Tum to blast off on a spice odyssey

Nothing but the best for British astronaut as chef Heston Blumenthal cooks up his rations
John Harrison's 'longitude' clock sets new record - 300 years on

‘Longitude’ clock sets new record - 300 years on

Greenwich horologists celebrate as it keeps to within a second of real time over a 100-day test
Fears in the US of being outgunned in the vital propaganda wars by Russia, China - and even Isis - have prompted a rethink on overseas broadcasters

Let the propaganda wars begin - again

'Accurate, objective, comprehensive': that was Voice of America's creed, but now its masters want it to promote US policy, reports Rupert Cornwell
Why Japan's incredible long-distance runners will never win the London Marathon

Japan's incredible long-distance runners

Every year, Japanese long-distance runners post some of the world's fastest times – yet, come next weekend, not a single elite competitor from the country will be at the London Marathon
Why does Tom Drury remain the greatest writer you've never heard of?

Tom Drury: The quiet American

His debut was considered one of the finest novels of the past 50 years, and he is every bit the equal of his contemporaries, Jonathan Franzen, Dave Eggers and David Foster Wallace
You should judge a person by how they peel a potato

You should judge a person by how they peel a potato

Dave Hax's domestic tips are reminiscent of George Orwell's tea routine. The world might need revolution, but we like to sweat the small stuff, says DJ Taylor
Beige is back: The drab car colours of the 1970s are proving popular again

Beige to the future

Flares and flounce are back on catwalks but a revival in ’70s car paintjobs was a stack-heeled step too far – until now
Bill Granger recipes: Our chef's dishes highlight the delicate essence of fresh cheeses

Bill Granger cooks with fresh cheeses

More delicate on the palate, milder, fresh cheeses can also be kinder to the waistline
Aston Villa vs Liverpool: 'This FA Cup run has been wonderful,' says veteran Shay Given

Shay Given: 'This FA Cup run has been wonderful'

The Villa keeper has been overlooked for a long time and has unhappy memories of the national stadium – but he is savouring his chance to play at Wembley
Timeless drama of Championship race in league of its own - Michael Calvin

Michael Calvin's Last Word

Timeless drama of Championship race in league of its own