Accelerated rise in sea levels blamed on global warming

A A A

Sea levels are rising twice as fast as they were 150 years ago and man-made greenhouse emissions are the prime cause, a study by scientists in America has found.

Tide lines worldwide are rising by about 2 millimetres a year, compared to 1 millimetre a year in 1850, said Kenneth Miller, professor of geology at Rutgers University in New Jersey.

The rate at which sea levels are rising is probably greater than at any time for thousands of years, suggesting that greenhouse emissions are accelerating climate change, he said.

"Without reliable information on how sea levels had changed before we had our new measures, we couldn't be sure the current rate wasn't happening all along," said Professor Miller. "Now with solid historical data, we know it is definitely a recent phenomenon."

The study was based on analysing the sediment of five core samples drilled to a depth of 500 metres off the New Jersey coast between Cape May and Sandy Hook. Analysing fossils, variations in radioactive isotopes and other chemical elements allowed scientists to make accurate estimates of sea levels at different times over the past 100 million years. This is the most reliable and comprehensive record of sea levels for this period of time, and is better than previous core samples drilled for commercial purposes, Professor Miller said.

The analysis, in the journal Science, showed there was a steady rise of about one millimetre a year in sea levels from 5,000 years ago until about 200 years ago. Recent measurements from tidal gauges and satellites show that the rate of increase in sea levels has doubled since 1850, he said.

"The main thing that's changed since the 19th century and the beginning of the modern observation has been the widespread increase in fossil fuel use and more greenhouse gases," the professor said. "Our record therefore provides a new and reliable baseline to use in addressing global warming."

Much of the rise in sea levels over the past century has been due to the thermal expansion of the oceans caused by rising sea temperatures because water increases slightly in volume when warmed. Melt water from mountain glaciers and the ice sheets of Antarctica and Greenland could cause a further dramatic increase in sea levels that would be big enough to inundate most of the worlds' coastal cities, including those on tidal rivers such as London.

A separate study published in Science has found further evidence to show that greenhouse gasses are at their highest levels in the atmosphere for thousands of years. Scientists analysed tiny air bubbles trapped in ice cores drilled into the Antarctic ice sheet, which can reveal the composition of the atmosphere going back more than 650,000 years, said Ed Brook, professor of geosciences at Oregon State University.

"The levels of primary greenhouse gases such as methane, carbon dioxide and nitrous oxide are up dramatically since the industrial revolution, at a speed and magnitude that the Earth has not seen in hundreds of thousands of years," he said.

Ice cores drilled from the ice sheets of Greenland and Antarctica are providing a valuable source of information on the rate of climate change. "We predict, for instance, that rising levels of greenhouse gases will warm our climate. There's evidence that this is happening right now, and it would be interesting to find out if the same thing has happened in the distant past," Professor Brook said.

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

Recruitment Genius: SAGE Bookkeeper & PA to Directors

£18000 - £24000 per annum: Recruitment Genius: An exciting opportunity has ari...

Recruitment Genius: Online Sales and Customer Services Executive

£15000 - £18000 per annum: Recruitment Genius: An On-line Sales & Customer Ser...

Recruitment Genius: Accounts Assistant - Fixed Term Contract - 6 Months

£15000 per annum: Recruitment Genius: One of the largest hospitality companies...

Recruitment Genius: Electricians - Fixed Wire Testing

£28000 - £32000 per annum: Recruitment Genius: As a result of significant cont...

Day In a Page

Seifeddine Rezgui: What motivated a shy student to kill 38 holidaymakers in Tunisia?

Making of a killer

What motivated a shy student to kill 38 holidaymakers in Tunisia?
UK Heatwave: Temperatures on the tube are going to exceed the legal limit for transporting cattle

Just when you thought your commute couldn't get any worse...

Heatwave will see temperatures on the Tube exceed legal limit for transporting cattle
Exclusive - The Real Stories of Migrant Britain: Swapping Bucharest for London

The Real Stories of Migrant Britain

Meet the man who swapped Romania for the UK in a bid to provide for his family, only to discover that the home he left behind wasn't quite what it seemed
Cheaper energy on the way, but it's not all sunshine and rainbows

Cheaper energy on the way, but it's not all sunshine and rainbows

Solar power will help bring down electricity prices over the next five years, according to a new report. But it’s cheap imports of ‘dirty power’ that will lower them the most
Katy Perry prevented from buying California convent for $14.5m after nuns sell to local businesswoman instead

No grace of God for Katy Perry as sisters act to stop her buying convent

Archdiocese sues nuns who turned down star’s $14.5m because they don’t approve of her
Ajmer: The ancient Indian metropolis chosen to be a 'smart city' where residents would just be happy to have power and running water

Residents just want water and power in a city chosen to be a ‘smart’ metropolis

The Indian Government has launched an ambitious plan to transform 100 of its crumbling cities
Michael Fassbender in 'Macbeth': The Scottish play on film, from Welles to Cheggers

Something wicked?

Films of Macbeth don’t always end well - just ask Orson Welles... and Keith Chegwin
10 best sun creams for body

10 best sun creams for body

Make sure you’re protected from head to toe in the heatwave
Wimbledon 2015: Nick Bollettieri - Milos Raonic has ability to get to the top but he must learn to handle pressure in big games

Nick Bollettieri's Wimbledon files

Milos Raonic has ability to get to the top but he must learn to handle pressure in big games
Women's World Cup 2015: How England's semi-final success could do wonders for both sexes

There is more than a shiny trophy to be won by England’s World Cup women

The success of the decidedly non-famous females wearing the Three Lions could do wonders for a ‘man’s game’ riddled with cynicism and greed
How to stop an asteroid hitting Earth: Would people co-operate to face down a global peril?

How to stop an asteroid hitting Earth

Would people cooperate to face a global peril?
Just one day to find €1.6bn: Greece edges nearer euro exit

One day to find €1.6bn

Greece is edging inexorably towards an exit from the euro
New 'Iron Man' augmented reality technology could help surgeons and firefighters, say scientists

'Iron Man' augmented reality technology could become reality

Holographic projections would provide extra information on objects in a person's visual field in real time
Sugary drinks 'are killing 184,000 adults around the world every year'

Sugary drinks are killing 184,000 adults around the world every year

The drinks that should be eliminated from people's diets
Pride of Place: Historians map out untold LGBT histories of locations throughout UK

Historians map out untold LGBT histories

Public are being asked to help improve the map