Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Penn-led Research Maps Historic Sea-level Change on the New Jersey Coastline

29.05.2013
Hurricane Sandy caught the public and policymakers off guard when it hit the United States’ Atlantic Coast last fall.
Because much of the storm’s devastation was wrought by flooding in the aftermath, researchers have been paying attention to how climate change and sea-level rise may have played a role in the disaster and how those factors may impact the shoreline in the future.

A new study led by the University of Pennsylvania’s Benjamin P. Horton, an associate professor in the Department of Earth and Environmental Science, relied upon fossil records of marshland to reconstruct the changes in sea level along the New Jersey coast going back 10,000 years.

The team’s findings confirm that the state’s sea level has risen continuously during that period. In addition, their analysis reveals that there have been times of very high rates of sea-level rise that coincided with periods of glacial melting, a particularly relevant finding to conditions today as a warming climate has caused the large ice sheets of Antarctica and Greenland to melt into the sea.

Even leaving climate change out of the equation, the investigation indicates that sea levels will continue to rise over time, increasing the chances of disruptive flooding as was seen following Sandy.

“We’re trying to better understand past sea-level changes because they are key to putting the future in context,” Horton said.

The study was published in the Journal of Quaternary Science. Horton’s co-authors were Simon E. Engelhart, who earned his doctorate at Penn and is now at the University of Rhode Island; David F. Hill of Oregon State University; Andrew C. Kemp, who earned his doctorate and completed a postdoctoral fellowship at Penn and is now at Yale University; Daria Nikitina of West Chester University; Kenneth G. Miller of Rutgers University; and W. Richard Peltier of the University of Toronto.

To gain insight into the variations in New Jersey’s past sea levels, the team compiled and standardized data from multiple studies conducted during the last few decades. All the studies used fossil evidence of marsh vegetation to estimate sea level at various times during the Holocene, with data points from 10,000 years ago through the year 1900.

“We knew that the sea level across the whole of the U.S. Atlantic Coast, including New Jersey, has been rising for the last 10,000 years,” Horton said. “But it’s been rising at different rates. We wanted to find out the reasons for the different rates of rise and the processes that control them.”

An analysis of the data revealed three distinct time periods in which the rate of sea-level rise varied. From 10,000 to 6,000 years ago the sea level rose an average of 4 millimeters per year: from 6,000 to 2,000 years ago 2 mm per year; from 2,000 years ago until 1900,1.3 mm per year.

This last figure, a sea-level rise of 1.3 mm per year, is due to the fact that the land along the coast is naturally subsiding, or sinking over time. This rate may serve as a baseline to incorporate into future flood-risk planning, Horton noted. And the 4 mm rate of rise last seen thousands of years ago may also be relevant to the New Jersey shore’s near future.

“If you look at what was happening 6 to 10,000 years ago, the ice sheets were melting on Earth, both from northwest Europe and North America, contributing to those high rates of rise,” Horton said. “Now what’s happening? Greenland and Antarctica are melting and could trigger similar rates of sea-level rise.”

But 4 mm may not be the ceiling for rates of rise. Sea-level rise was higher than that even earlier than 10,000 years ago and could reach those rates again if climate change triggers catastrophic melting of ice sheets.

“Ice sheets don’t respond linearly to temperature rise; they go through thresholds,” Horton said. “That could lead to far higher rates of sea-level rise if they reach one of these tipping points.”

Local factors could also drive the rate of rise much higher than 4 mm per year. While the scientists’ analysis did not suggest that tidal ranges have changed significantly in the time range they studied, anthropogenic factors, such as dredging in the Delaware Bay or groundwater extraction in the Atlantic City region, could serve to increase tides or sediment compaction, thus effectively driving sea level higher in those areas.

“To model what the ocean is doing, you have to incorporate what the land is doing, too,” Horton said. “This is the way we’re starting to go from global to regional projections of sea level.”

This study was supported by the U.S. Department of Energy, National Science Foundation and National Oceanic and Atmospheric Administration.

Evan Lerner | EurekAlert!
Further information:
http://www.upenn.edu

More articles from Earth Sciences:

nachricht Stagnation in the South Pacific Explains Natural CO2 Fluctuations
23.02.2018 | Carl von Ossietzky-Universität Oldenburg

nachricht First evidence of surprising ocean warming around Galápagos corals
22.02.2018 | University of Arizona

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Basque researchers turn light upside down

23.02.2018 | Physics and Astronomy

Finnish research group discovers a new immune system regulator

23.02.2018 | Health and Medicine

Attoseconds break into atomic interior

23.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>