Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ocean Salinity Trends Show Human Fingerprint

02.11.2012
Changes in ocean salinity over the second half of the 20th Century are consistent with the influence of human activities and inconsistent with natural climate variations, according to a new study.

Observed changes agree with computer modeling of salinity trends in a steadily warming world, said Scripps Institution of Oceanography, UC San Diego, climate researcher David Pierce, the study's lead author.

Ocean salinity changes are driven by the world's patterns of evaporation and rainfall, which themselves are changing. Observations over recent decades have found a general intensification of salinity differences in which salty ocean regions experience even more evaporation of surface waters and relatively fresh regions are becoming even more diluted with precipitation. These patterns are part of global changes in precipitation and evaporation.

Pierce said the significance of the study is that it provides an independent check of the effects of climate change on the water cycle using different instruments and techniques than weather station rainfall measurements. Studies of rainfall over land are harder to measure and place in context because of changes to weather stations over the years and the episodic nature of storms.

"The salinity in the ocean averages out all that variability," said Pierce. The paper will be published 2 November in the American Geophysical Union journal Geophysical Research Letters. Co-authors include Peter J. Gleckler, Benjamin Santer and Paul Durack of the Lawrence Livermore National Laboratory in Livermore, Calif. and Tim Barnett of Scripps Oceanography.

The study builds on previous analyses conducted in the last decade by Barnett, Pierce and others. They demonstrated that rising temperatures in the upper 700 meters (2,000 feet) of the ocean also can only be explained by anthropogenic climate change, which is caused mostly by an accumulation of carbon dioxide created by fossil fuel use.

This research complements the temperature analysis by considering salinity, the other main factor that determines the density of ocean water. Ocean water density is a key factor determining how water moves in the oceans.

"By combining the analysis of salinity and temperature, this study brings our level of understanding global scale oceanic changes to a new level," said Gleckler.

The previous temperature studies and this analysis of ocean salinity use a technique known as detection and attribution. In this method, observed trends in ocean salinity are compared to the effects of various historical phenomena such as volcanic eruptions or solar fluctuations and to climate cycles such as El Niño. When the computer climate models were run, the influence of those phenomena does not replicate the salinity or temperature patterns that researchers have observed since 1955. Only when the warming trends associated with human activity were added could the observed salinity trends and temperature changes be explained.

The research performed in this study will likely contribute to the next report of the Intergovernmental Panel on Climate Change, scheduled to be released in phases beginning in 2013.

The U.S. Department of Energy and NOAA funded the research.

Notes for Journalists

Journalists and public information officers (PIOs) of educational and scientific institutions who have registered with AGU can download a PDF copy of this paper in press by clicking on this link: http://dx.doi.org/10.1029/2012GL053389

Or, you may order a copy of the paper by emailing your request to Kate Ramsayer at kramsayer@agu.org. Please provide your name, the name of your publication, and your phone number.


Title:
"The fingerprint of human-induced changes in the ocean's salinity and temperature fields"
Authors:
David W. Pierce: Division of Climate, Atmospheric Sciences, and Physical Oceanography,

Scripps Institution of Oceanography, La Jolla, California, USA;

Peter J. Gleckler: Program for Climate Model Diagnosis and Intercomparison, Lawrence Livermore National Laboratory, Livermore, California, USA;

Tim P Barnett: Division of Climate, Atmospheric Sciences, and Physical Oceanography, Scripps Institution of Oceanography, La Jolla, California, USA;

Benjamin D. Santer and Paul James Durack: Program for Climate Model Diagnosis and Intercomparison, Lawrence Livermore National Laboratory, Livermore, California, USA;

Contact information for the authors:
Dave Pierce, Telephone: (858) 534-8276, email: dpierce@ucsd.edu.

Kate Ramsayer | American Geophysical Union
Further information:
http://www.agu.org

More articles from Earth Sciences:

nachricht Multi-year submarine-canyon study challenges textbook theories about turbidity currents
12.12.2017 | Monterey Bay Aquarium Research Institute

nachricht How do megacities impact coastal seas? Searching for evidence in Chinese marginal seas
11.12.2017 | Leibniz-Institut für Ostseeforschung Warnemünde

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

A whole-body approach to understanding chemosensory cells

13.12.2017 | Health and Medicine

Water without windows: Capturing water vapor inside an electron microscope

13.12.2017 | Physics and Astronomy

Cellular Self-Digestion Process Triggers Autoimmune Disease

13.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>