Scientists use salt marshes to analyse global sea-level rise

May 06, 2013

(Phys.org) —The world's salt marshes could hold the key to predicting future sea levels after scientists used them to pinpoint when recent rises began.

Scientists analysed sediments and fossils buried in which show the recent rise in – posing a threat to millions of coastal homes worldwide – began around a century ago.

Professor Roland Gehrels, from Plymouth University, and Professor Philip Woodworth, of the National Oceanography Centre in Liverpool, say this can be linked to the general rise in temperatures and supports theories that global warming is melting caps and glaciers and impacting on sea levels across the globe.

Professor Gehrels, from the University's School of Geography, Earth and Environmental Sciences, said: "All over the globe low-lying are living with the threat of from levels. In order to make meaningful predictions of future sea-level rise, we need to understand what the underlying mechanisms were that drove historical variations. Our goal is to account for all possible contributions in the recent past to alleviate the uncertainties associated with predictions of future sea-level change."

The first systematic measurements of sea level from direct observations date back to the late 17th century, but it was not until the mid-19th century that the first 'automatic' tide gauges were developed.

For their research, Professor Gehrels and Professor Woodworth used data from cores of salt-marsh sediments taken from a number of sites in both the northern and southern hemisphere.

Within these cores are tiny fossilised , which scientists can use to determine how much new sediment has been deposited by incoming tides and how much levels have risen over many centuries.

Using this technique, the scientists were able to chart sea levels going back almost 4,000 years, allowing them to date the onset of the modern sea-level rise as the early years of the 20th century.

Professor Gehrels added: "The timing of the change was relatively uniform throughout the globe, suggesting that the influx of water came from a terrestrial source – melting land ice. But the magnitude of change was not uniform, being larger in the southern hemisphere than the northern hemisphere, which indicates the water was released from ice in the northern hemisphere. The results therefore support the theory that modern rates of sea-level rise were triggered by the melting of the Greenland Ice Sheet and Arctic glaciers."

Explore further: US delays decision on Keystone pipeline project

add to favorites email to friend print save as pdf

Related Stories

Southern sea levels rise drastically

Apr 12, 2012

(Phys.org) -- Sea levels have risen about 20cm in the South West Pacific since the late 19th century, a new scientific study shows.

Melting ice the greatest factor in rising sea levels

Jul 04, 2012

Melting glaciers and ice sheets have contributed more to rising sea levels in the past decade than expansion from warming water, according to modelling in the latest report by the Antarctic Climate and Ecosystems ...

Melting glaciers raise sea level

Nov 14, 2012

Anthropogenic climate change leads to melting glaciers and rising sea level. Between 1902 and 2009, melting glaciers contributed 11 cm to sea level rise. They were therefore the most important cause of sea ...

Storminess helps coastal marshes withstand sea level rise

Feb 11, 2013

Rising sea levels are predicted to threaten many coastal sea marshes around the world in the coming decades as the Earth's climate warms. In addition to accelerating sea level rise, global climate change is predicted to increase ...

Recommended for you

US delays decision on Keystone pipeline project

14 hours ago

The United States announced Friday a fresh delay on a final decision regarding a controversial Canada to US oil pipeline, saying more time was needed to carry out a review.

New research on Earth's carbon budget

20 hours ago

(Phys.org) —Results from a research project involving scientists from the Desert Research Institute have generated new findings surrounding some of the unknowns of changes in climate and the degree to which ...

User comments : 0

More news stories

Magnitude-7.2 earthquake shakes Mexican capital

A powerful magnitude-7.2 earthquake shook central and southern Mexico on Friday, sending panicked people into the streets. Some walls cracked and fell, but there were no reports of major damage or casualties.

New research on Earth's carbon budget

(Phys.org) —Results from a research project involving scientists from the Desert Research Institute have generated new findings surrounding some of the unknowns of changes in climate and the degree to which ...

Health care site flagged in Heartbleed review

People with accounts on the enrollment website for President Barack Obama's signature health care law are being told to change their passwords following an administration-wide review of the government's vulnerability to the ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.