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 email@example.com. Please provide your name, the name of your publication, and your phone number.
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:
Kate Ramsayer | American Geophysical Union
How is climate change affecting fauna in the Arctic?
22.05.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
Sea level as a metronome of Earth's history
19.05.2017 | Université de Genève
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.
In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...
Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...
For the first time, scientists have succeeded in studying the strength of hydrogen bonds in a single molecule using an atomic force microscope. Researchers from the University of Basel’s Swiss Nanoscience Institute network have reported the results in the journal Science Advances.
Hydrogen is the most common element in the universe and is an integral part of almost all organic compounds. Molecules and sections of macromolecules are...
22.05.2017 | Event News
17.05.2017 | Event News
16.05.2017 | Event News
22.05.2017 | Materials Sciences
22.05.2017 | Life Sciences
22.05.2017 | Physics and Astronomy