Floods could overwhelm London as sea levels rise - unless Thames Barrier is upgraded

Study concludes there is 1 in 20 chance that existing defences would be unable to cope with extreme storm surge

Science Editor

A A A

There is significant risk of London being hit by a devastating storm surge in the Thames estuary by 2100 that could breach existing flood defences and cause immense damage to the capital, a study of global sea-level rise has found.

Melting of polar ice sheets and mountain glaciers could increase sea levels significantly over the coming decades leading to a 1 in 20 risk that the existing Thames Barrier would be unable to cope with an extreme storm surge, the study concluded.

Extreme storm surges that can breach the barrier would in the past have occurred with a frequency of about 1 in 1,000 years, but in a warmer world they could occur as frequently as 1 in every 10 years, scientists said.

The increased threat posed by rising sea levels is one of the reasons why flood defences around the Thames estuary and the barrier itself will be strengthened.

An international panel of glaciologists and climate scientists said there is still huge uncertainty about how sea levels will change in the coming century as a result of climate change and its effect on polar ice sheets and mountain glaciers.

Their best estimate is that the melting ice on its own will contribute between 3.5cm and 36.8cm to mean sea levels, which would come on top of the rise in sea level due to other factors such as the thermal expansion of the warmer oceans.

However, there is a 1 in 20 risk of this being a wild underestimate and that melting polar ice and mountain glaciers alone would contribute more than 84cm to global sea level, which would lead to rises of about a metre around Britain if other factors are taken into account, they said.

"The Thames Barrier was built to provide London with a level of protection that would only be exceeded in about 1 in every 1,000 years. So in any one year the likelihood of exceeding this is about 0.1 per cent," said Professor David Vaughan of the British Antarctic Survey.

"With 50cm of sea level rise we would expect that level of protection to go down from 1 in 1,000 years to about 1 in 100 years, so under that scenario in every year there would be a 1 per cent chance of flooding. If you have a metre rise you go down from 1 in 1,000 years to 1 in 10 years," Professor Vaughan said.

These estimates are based on existing "business as usual" emissions of carbon dioxide, leading to about a 3.5C rise in mean global temperature by 2100. Greater emissions would lead to higher temperatures and faster melting, the scientists said.

How sea-level rise and polar ice sheets will respond to rising temperatures is one of the greatest uncertainties in climate science. The research programme, called Ice 2 Sea, was established by the UN's Intergovernmental Panel on Climate Change to estimate the future contribution to sea level from melting ice.

"There is still extra uncertainty that arises because our models are not complete. There are still processes that we think are important but we haven't been able to include in our models," said Professor Vaughan, the coordinator of the programme.

The scientists carried out "expert elicitation" among themselves to take into account the unknowns that their computer models were unable to include, Professor Vaughan said.

"That has come up with this number: there is less than a 1 in 20 risk of ice sheets and glaciers contributing more than 84cms to sea level rise by 2100. That is trying to capture those climate processes that we suspect are important yet are not fully included in existing models," he said.

Sea levels would rise by varying degrees around the world due to melting ice, and would even decline in areas around Greenland and Antarctica due to the diminished gravitational pull of the dwindling ice sheets. The British coastline would see sea level rises that are slightly below the global average, Professor Vaughan said.

"It is likely that some future ice loss and sea level rise is now unavoidable. But nevertheless, understanding why changes are occurring today and how they could increase in the future is the first step in maintaining the security of our coastal regions for future generations," he said.

News
The Banksy image in Folkestone before it was vandalised
people
Life and Style
tech

Sales of the tablet are set to fall again, say analysts

Sport
football West Brom vs Man Utd match report: Blind grabs point, but away form a problem for Van Gaal
News
i100
PROMOTED VIDEO
Have you tried new the Independent Digital Edition apps?
Arts and Entertainment
Bloom Time: Mira Sorvino
tvMira Sorvino on leaving movie roles for 'The Intruders'
News
Brian Harvey turned up at Downing Street today demanding to speak to the Prime Minister
news

Met Police confirm there was a 'minor disturbance' and that no-one was arrested

Arts and Entertainment
George Lucas poses with a group of Star Wars-inspired Disney characters at Disney's Hollywood Studios in 2010
films

George Lucas criticises the major Hollywood film studios

Voices
Chris Grayling, Justice Secretary: 'There are pressures which we are facing but there is not a crisis'
voices

Does Chris Grayling realise what a vague concept he is dealing with?

Life and Style
A street vendor in Mexico City sells Dorilocos, which are topped with carrot, jimaca, cucumber, peanuts, pork rinds, spices and hot sauce
food + drink

Trend which requires crisps, a fork and a strong stomach is sweeping Mexico's streets

News
Blackpool is expected to become one of the first places to introduce the Government’s controversial new Public Space Protection Orders (PSPOs)
news

Concerns raised phenomenon is threatening resort's image as a family destination

Life and Style
Northern soul mecca the Wigan Casino
fashionGone are the punks, casuals, new romantics, ravers, skaters, crusties. Now all kids look the same
Life and Style
gaming

I Am Bread could actually be a challenging and nuanced title

Life and Style
The charity Sands reports that 11 babies are stillborn everyday in the UK
lifeEleven babies are stillborn every day in the UK, yet no one speaks about this silent tragedy
News
Nigel Farage has backed DJ Mike Read's new Ukip song
i100
Voices
The number of children in relative income poverty is currently 2.3 million in the UK
voices

Environment
A Brazilian wandering spider
natureIt's worth knowing for next time one appears in your bananas
Life and Style
Time and Oak have developed a product that allows drinkers to customise the flavour and improve the quality of cheaper whiskey
food + drink

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

Year 5 Teacher

£80 - £140 per day: Randstad Education Leeds: Year 5 Teacher KS2 teaching job...

Software Developer

£35000 - £45000 Per Annum Pensions Scheme After 6 Months: Clearwater People So...

Systems Analyst / Business Analyst - Central London

£35000 - £37000 per annum + Benefits: Ashdown Group: Systems Analyst / Busines...

Senior Change Engineer (Network, Cisco, Juniper) £30k

£30000 - £35000 per annum + Benefits: Ampersand Consulting LLP: Senior Change ...

Day In a Page

Oscar Pistorius sentencing: The athlete's wealth and notoriety have provoked a long overdue debate on South African prisons

'They poured water on, then electrified me...'

If Oscar Pistorius is sent to jail, his experience will not be that of other inmates
James Wharton: The former Guard now fighting discrimination against gay soldiers

The former Guard now fighting discrimination against gay soldiers

Life after the Army has brought new battles for the LGBT activist James Wharton
Ebola in the US: Panic over the virus threatens to infect President Obama's midterms

Panic over Ebola threatens to infect the midterms

Just one person has died, yet November's elections may be affected by what Republicans call 'Obama's Katrina', says Rupert Cornwell
Premier League coaches join the RSC to swap the tricks of their trades

Darling, you were fabulous! But offside...

Premier League coaches are joining the RSC to learn acting skills, and in turn they will teach its actors to play football. Nick Clark finds out why
How to dress with authority: Kirsty Wark and Camila Batmanghelidjh discuss the changing role of fashion in women's workwear

How to dress with authority

Kirsty Wark and Camila Batmanghelidjh discuss the changing role of fashion in women's workwear
New book on Joy Division's Ian Curtis sheds new light on the life of the late singer

New book on Ian Curtis sheds fresh light on the life of the late singer

'Joy Division were making art... Ian was for real' says author Jon Savage
Sean Harris: A rare interview with British acting's secret weapon

Sean Harris: A rare interview with British acting's secret weapon

The Bafta-winner talks Hollywood, being branded a psycho, and how Barbra Streisand is his true inspiration
Tim Minchin, interview: The musician, comedian and world's favourite ginger is on scorching form

Tim Minchin interview

For a no-holds-barred comedian who is scathing about woolly thinking and oppressive religiosity, he is surprisingly gentle in person
Boris Johnson's boozing won't win the puritan vote

Boris's boozing won't win the puritan vote

Many of us Brits still disapprove of conspicuous consumption – it's the way we were raised, says DJ Taylor
Ash frontman Tim Wheeler reveals how he came to terms with his father's dementia

Tim Wheeler: Alzheimer's, memories and my dad

Wheeler's dad suffered from Alzheimer's for three years. When he died, there was only one way the Ash frontman knew how to respond: with a heartfelt solo album
Hugh Bonneville & Peter James: 'Peter loves his classic cars; I've always pootled along fine with a Mini Metro. I think I lack his panache'

How We Met: Hugh Bonneville & Peter James

'Peter loves his classic cars; I've always pootled along fine with a Mini Metro. I think I lack his panache'
Bill Granger recipes: Our chef's heavenly crab dishes don't need hours of preparation

Bill Granger's heavenly crab recipes

Scared off by the strain of shelling a crab? Let a fishmonger do the hard work so you can focus on getting the flavours right
Radamel Falcao: How faith and love drive the Colombian to glory

Radamel Falcao: How faith and love drive the Colombian to glory

After a remarkable conversion from reckless defender to prolific striker, Monaco's ace says he wants to make his loan deal at Old Trafford permanent
Terry Venables: Premier League managers must not be allowed to dictate who plays and who does not play for England

Terry Venables column

Premier League managers must not be allowed to dictate who plays and who does not play for England
The Inside Word: Brendan Rodgers looks to the future while Roy Hodgson is ghost of seasons past

Michael Calvin's Inside Word

Brendan Rodgers looks to the future while Roy Hodgson is ghost of seasons past