Posts Tagged ‘oceans’

New Estimate of Glacier Melt Less Than Previously Thought

NAU geographer Erik Schiefer in British Columbia studying glacier melt. (Photo by Karl Schiefer)

NAU geographer Erik Schiefer in British Columbia studying glacier melt. (Photo by Karl Schiefer)

The melting of glaciers is well documented, but when looking at the rate at which they have been retreating, a team of international researchers steps back and says not so fast.

Previous studies have largely overestimated mass loss from Alaskan glaciers over the past 40-plus years, according to Erik Schiefer, a Northern Arizona University geographer who coauthored a paper in the February issue of Nature Geoscience that recalculates glacier melt in Alaska.

The research team, led by Étienne Berthier of the Laboratory for Space Studies in Geophysics and Oceanography at the Université de Toulouse in France, says that glacier melt in Alaska between 1962 and 2006 contributed about one-third less to sea-level rise than previously estimated.

Schiefer said melting glaciers in Alaska originally were thought to contribute about .0067 inches to sea-level rise per year. The team’s new calculations put that number closer to .0047 inches per year. The numbers sound small, but as Schiefer said, “It adds up over the decades.” (more…)

Possibly Related Posts:



Researchers Measure Impacts of Changing Climate on Ocean Biology

A bongo net, used to capture plankton, is recovered aboard the Delaware II. (Credit: Jerry Prezioso, NOAA)

A bongo net, used to capture plankton, is recovered aboard the Delaware II. (Credit: Jerry Prezioso, NOAA)

A three-year field program now underway is measuring carbon distributions and primary productivity in the Northwest Atlantic Ocean to help scientists worldwide determine the impacts of a changing climate on ocean biology and biogeochemistry. The study, Climate Variability on the East Coast (CliVEC), will also help validate ocean color satellite measurements and refine biogeochemistry models of ocean processes.

Researchers from NOAA, NASA and Old Dominion University are collaborating through an existing NOAA Fisheries Service field program, the Ecosystem Monitoring or EcoMon program.  The EcoMon surveys are conducted six times each year by the Northeast Fisheries Science Center (NEFSC) at 120 randomly selected stations throughout the continental shelf and slope of the northeastern U.S., from Cape Hatteras, N.C., into Canadian waters to cover all of Georges Bank and the Gulf of Maine. This area is known as the Northeast U.S. continental shelf Large Marine Ecosystem.

The climate study team will participate in three annual EcoMon cruises aboard the 155-foot NOAA Fisheries Survey Vessel Delaware II, based at the NEFSC’s laboratory in Woods Hole, Mass. The most recent cruise returned to Woods Hole on February 18.

Findings from the climate impact project, funded by NASA, will help scientists better understand how annual and decadal-scale climate variability affects the growth of phytoplankton, which is the basis of the oceanic food chain. The project will also examine organic carbon distributions along the continental margin of the East Coast and collect data for ocean acidification studies. (more…)

Possibly Related Posts:



Ocean Geoengineering Scheme No Easy Fix for Global Warming

This map displays simulated additional surface warming (in Celsius) for the year 2100 caused by the temporary use of artificial upwelling in the green areas for the time period 2011-2060. (IFM-GEOMAR)

This map displays simulated additional surface warming (in Celsius) for the year 2100 caused by the temporary use of artificial upwelling in the green areas for the time period 2011-2060. (IFM-GEOMAR)

Pumping nutrient-rich water up from the deep ocean to boost algal growth in sunlit surface waters and draw carbon dioxide down from the atmosphere has been touted as a way of ameliorating global warming. However, a new study led by Professor Andreas Oschlies of the Leibniz Institute of Marine Sciences (IFM-GEOMAR) in Kiel, Germany, pours cold water on the idea.

“Computer simulations show that climatic benefits of the proposed geo-engineering scheme would be modest, with the potential to exacerbate global warming should it fail,” said study co-author Dr Andrew Yool of the National Oceanography Centre, Southampton (NOCS).

If international governmental policies fail to reduce emissions of carbon dioxide to levels needed to keep the impacts of human-induced climate change within acceptable limits it may necessary to move to ‘Plan B’. This could involve the implementation of one or more large-scale geo-engineering schemes proposed for reducing the carbon dioxide increase in the atmosphere. (more…)

Possibly Related Posts:



Research Challenges Models of Sea Level Change During Ice-Age Cycles

by Gary Galluzzo

ice-age-cyclesTheories about the rates of ice accumulation and melting during the Quaternary Period — the time interval ranging from 2.6 million years ago to the present — may need to be revised, thanks to research findings published by a University of Iowa researcher and his colleagues in the Feb. 12 issue of the journal Science.

Jeffrey Dorale, assistant professor of geoscience in the UI College of Liberal Arts and Sciences, writes that global sea level and Earth’s climate are closely linked. Data he and colleagues collected on speleothem encrustations (see photo right), a type of mineral deposit, in coastal caves on the Mediterranean island of Mallorca indicate that sea level was about one meter above present-day levels around 81,000 years ago. The finding challenges other data that indicate sea level was as low as 30 meters — the ice equivalent of four Greenland ice sheets — below present-day levels.

He said the sea level high stand of 81,000 years ago was preceded by rapid ice melting, on the order of 20 meters of sea level change per thousand years and the sea level drop following the high water mark, accompanied by ice formation, was equally rapid.

“Twenty meters per thousand years equates to one meter of sea level change in a 50-year period,” Dorale said. “Today, over one-third of the world’s population lives within 60 miles of the coastline. Many of these areas are low-lying and would be significantly altered — devastated — by a meter of sea level rise. Our findings demonstrate that changes of this magnitude can happen naturally on the timescale of a human lifetime. Sea level change is a very big deal.” (more…)

Possibly Related Posts:



Oceans Reveal Further Impacts of Climate Change

Antarctic marine biologist Jim McClintock.

Antarctic marine biologist Jim McClintock.

The increasing acidity of the world’s oceans - and that acidity’s growing threat to marine species - are definitive proof that the atmospheric carbon dioxide that is causing climate change is also negatively affecting the marine environment, says world-renowned Antarctic marine biologist Jim McClintock, Ph.D., professor in the University of Alabama at Birmingham (UAB) Department of Biology.

“The oceans are a sink for the carbon dioxide that is released into the atmosphere,” says McClintock, who has spent more than two decades researching the marine species off the coast of Antarctica. Carbon dioxide is absorbed by oceans, and through a chemical process hydrogen ions are released to make seawater more acidic.

“Existing data points to consistently increasing oceanic acidity, and that is a direct result of increasing carbon dioxide levels in the atmosphere; it is incontrovertible,” McClintock says. “The ramifications for many of the organisms that call the water home are profound.”

A substance’s level of acidity is measured by its pH value; the lower the pH value, the more acidic is the substance. McClintock says data collected since the pre-industrial age indicates the mean surface pH of the oceans has declined from 8.2 to 8.1 units with another 0.4 unit decline possible by century’s end. A single whole pH unit drop would make ocean waters 10 times more acidic, which could rob many marine organisms of their ability to produce protective shells - and tip the balance of marine food chains.

“There is no existing data that I am aware of that can be used to debate the trend of increasing ocean acidification,” he says. (more…)

Possibly Related Posts:



Measuring Carbon Dioxide Over the Ocean

The Norwegian weather ship Polarfront is equipped with a battery of instruments to measure wind speed, humidity and carbon dioxide. (Margaret Yelland /NOCS)

The Norwegian weather ship Polarfront is equipped with a battery of instruments to measure wind speed, humidity and carbon dioxide. (Margaret Yelland /NOCS)

Reliable measurements of the air-sea flux of carbon dioxide – an important greenhouse gas – are needed for a better understanding of the impact of ocean-atmosphere interactions on climate. A new method developed by researchers at the National Oceanography Centre, Southampton (NOCS) working in collaboration with colleagues at the Bjerknes Center for Climate Research (Bergen, Norway) promises to make this task considerably easier.

Infrared gas sensors measure carbon dioxide based on its characteristic absorption spectra and are used to evaluate the air-sea flux of the gas. So-called closed-path sensors precondition air before measurements are made, while open-path sensors can be used to measure the air in situ.

One advantage of using open-path sensors at sea is that wind measurements can be taken contemporaneously in the same place. Moreover, because they are small and don’t use much power they can be used on buoys.

“Open-path sensors have the potential greatly to increase our understanding of the variability of air-sea carbon dioxide fluxes,” said PhD student John Prytherch of the University of Southampton’s School of Ocean and Earth Science at NOCS.

However, a long-standing concern has been that the values from open-path sensors do not tally with those from closed-path sensors, or with measurements made using other techniques. (more…)

Possibly Related Posts:



Echinoderms Contribute to Global Carbon Sink

Echinoderms such as brittle stars bury significant amounts of carbon at the seabed when they die and decay. (SERPENT)

Echinoderms such as brittle stars bury significant amounts of carbon at the seabed when they die and decay. (SERPENT)

The impact on levels of carbon dioxide in the Earth’s atmosphere by the decaying remains of a group of marine creatures that includes starfish and sea urchin has been significantly underestimated.

“Climate models must take this carbon sink into account,” says Mario Lebrato, lead author of the study. The work was done when he was at the National Oceanography Centre, Southampton (NOCS) and affiliated with the University of Southampton’s School of Ocean and Earth Science (SOES); he is now at the Leibniz Institute of Marine Science in Germany.

Globally, the seabed habitats occupy more than 300 million million square metres, from the intertidal flats and pools to the mightiest deep-sea trenches at 11,000 meters. The benthos – the animals living on and in the sediments – populate this vast ecosystem.

Calcifying organisms incorporate carbon directly from the seawater into their skeletons in the form of inorganic minerals such as calcium carbonate. This means that their bodies contain a substantial amount of inorganic carbon. When they die and sink, some of the inorganic carbon is remineralised, and much of it becomes buried in sediments, where it remains locked up indefinitely. (more…)

Possibly Related Posts:



Understanding Ocean Climate Change

This image shows ocean temperature at the 100 m depth and sea ice thickness in Sept. 2006 from the 8 km resolution global model. (NOCS)

This image shows ocean temperature at the 100 m depth and sea ice thickness in Sept. 2006 from the 8 km resolution global model. (NOCS)

High-resolution computer simulations performed by scientists at the National Oceanography Centre, Southampton (NOCS) are helping to understand the inflow of North Atlantic water to the Arctic Ocean and how this influences ocean climate.

The summer of 2007 saw a record retreat in Arctic sea ice, and in general Arctic climate has become steadily warmer since the early 1990s. This has changed both sea ice drift and upper ocean circulation.

The warm North Atlantic water intrudes into the central Arctic Ocean through Fram Strait, the deep channel between Greenland and Spitsbergen that connects the Nordic Seas to the Arctic Ocean, contributing to sea ice melting.

“We need to understand what is going on because changes in the Arctic Ocean can influence climate around the world,” said Dr Yevgeny Aksenov of NOCS: “The worry is that freshwater from melting ice and increased atmospheric precipitation in the Arctic could ultimately slow the overturning circulation of the North Atlantic, with serious consequences for global climate.” (more…)

Possibly Related Posts:



Oceans Absorbing Carbon Dioxide More Slowly, Yale Scientist Finds

oceans-absorbing-carbon-dioxide-more-slowlyThe world’s oceans are absorbing less carbon dioxide (CO2), a Yale geophysicist has found after pooling data taken over the past 50 years. With the oceans currently absorbing over 40 percent of the CO2 emitted by human activity, this could quicken the pace of climate change, according to the study, which appears in the November 25 issue of Geophysical Research Letters.

Jeffrey Park, professor of geology and geophysics and director of the Yale Institute for Biospheric Studies, used data collected from atmospheric observing stations in Hawaii, Alaska and Antarctica to study the relationship between fluctuations in global temperatures and the global abundance of atmospheric CO2 on interannual (one to 10 years) time scales. A similar study from 20 years ago found a five-month lag between interannual temperature changes and the resulting changes in CO2 levels. Park has now found that this lag has increased from five to at least 15 months.

“No one had updated the analysis from 20 years ago,” Park said. “I expected to find some change in the lag time, but the shift was surprisingly large. This is a big change.” (more…)

Possibly Related Posts:



Engineers Use Aerospace Approach to Design Wave Energy System

ocean-wave-83The ocean is a potentially vast source of electric power, yet as engineers test new technologies for capturing it, the devices are plagued by battering storms, limited efficiency, and the need to be tethered to the seafloor.

Now, a team of aerospace engineers is applying the principles that keep airplanes aloft to create a new wave-energy system that is durable, extremely efficient, and can be placed anywhere in the ocean, regardless of depth.

While still in early design stages, computer and scale-model tests of the system suggest higher efficiencies than wind turbines. The system is designed to effectively cancel incoming waves, capturing their energy while flattening them out, providing an added application as a storm-wave breaker.

The researchers, from the U.S. Air Force Academy, will present their design at the 62nd annual meeting of the American Physical Society’s Division of Fluid Dynamics on Nov. 24, 2009, in Minneapolis, Minn.

“Our group was working on very basic research on feedback flow control for years,” says lead researcher Stefan Siegel, referring to efforts to use sensors and adjustable parts to control how fluids flow around airfoils like wings. “For an airplane, when you control that flow, you better control flight–for example, enabling you to land a plane on a shorter runway.” (more…)

Possibly Related Posts:



Deep-Sea Ecosystems Affected by Climate Change

A deep-sea urchin crawls across the muddy seafloor at Station M, about 220 kilometers off the California coast and 4,000 meters below the sea surface. After studying these and other deep-sea animals, Smith's group has seen their populations change dramatically from one year to another. Image: © 2007 MBARI

A deep-sea urchin crawls across the muddy seafloor at Station M, about 220 kilometers off the California coast and 4,000 meters below the sea surface. After studying these and other deep-sea animals, Smith's group has seen their populations change dramatically from one year to another. Image: © 2007 MBARI

The vast muddy expanses of the abyssal plains occupy about 60 percent of the Earth’s surface and are important in global carbon cycling. Based on long-term studies of two such areas, a new paper in the Proceedings of the National Academy of Sciences (PNAS) shows that animal communities on the abyssal seafloor are affected in a variety of ways by climate change.

Historically, many people, including marine scientists, have considered the abyssal plains, more than 2,000 meters below the sea surface, to be relatively isolated and stable ecosystems. However, according to Ken Smith, a marine ecologist at the Monterey Bay Aquarium Research Institute (MBARI) and lead author of the recent PNAS article, changes in the Earth’s climate can cause unexpectedly large changes in deep-sea ecosystems. Based on 18 years of studies, Smith and his coauthors show that such ecosystem changes occur over short time scales of weeks to months, as well as over longer periods of years to decades.

The recent paper covers two time-series studies—one at “Station M,” about 220 kilometers off the Central California coast, and a second on the Porcupine Abyssal Plain, several hundred kilometers southwest of Ireland. The flat, muddy seafloor at these sites lies between 4,000 and 5,000 meters beneath the ocean surface. (more…)

Possibly Related Posts:



Iron Controls Patterns of Nitrogen Fixation in the Atlantic, Affecting CO2 Sequester Ability

This is the experimental set-up on the Royal Research Ship Discovery. (Dr Mark Moore (NOCS))

This is the experimental set-up on the Royal Research Ship Discovery. (Dr Mark Moore (NOCS))

Scientists including researchers from the National Oceanography Centre, Southampton and the University of Essex have discovered that interactions between iron supply, transported through the atmosphere from deserts, and large-scale oceanic circulation control the availability of a crucial nutrient, nitrogen, in the Atlantic. Their findings have potentially important implications for understanding global climate, both past and future.

Nitrogen is an essential element for life, but in its gaseous form (N2) cannot be used by most organisms. To be useful, nitrogen has to be ‘fixed’ by combining it with other chemicals to form compounds such as ammonium. ‘Diazotrophic’ microbes such as the blue-green bacterium Trichodesmium are equipped with the enzymes needed to perform these energy-demanding transformations. (more…)

Possibly Related Posts:



Tropical Regions To Be Hardest Hit By Fisheries Shifts Caused By Climate Change

UBC Fisheries professor Daniel Pauly

UBC Fisheries professor Daniel Pauly

Major shifts in fisheries distribution due to climate change will affect food security in tropical regions most adversely, according to a study led by the Sea Around Us Project at The University of British Columbia.

In the first major study to examine the effects of climate change on ocean fisheries, a team of researchers from UBC and Princeton University finds that climate change will produce major shifts in productivity of the world’s fisheries, affecting ocean food supply throughout the world. The study is published today in the journal Global Change Biology.

“Our projections show that climate change may lead to a 30 to 70 per cent increase in catch potential in high-latitude regions and a drop of up to 40 per cent in the tropics,” says lead author William Cheung, a researcher at the University of East Anglia in the UK who conducted the study while at UBC.

“Many tropical island residents rely heavily on the oceans for their daily meals. These new findings suggest there’s a good chance this important food source will be greatly diminished due to climate change.” (more…)

Possibly Related Posts:



Impact of Renewable Energy on our Oceans Must Be Investigated, Say Scientists

off-shore-wind-farmsScientists from the Universities of Exeter and Plymouth are today calling for urgent research to understand the impact of renewable energy developments on marine life. The study, now published in the Journal of Applied Ecology, highlights potential environmental benefits and threats resulting from marine renewable energy, such as off-shore wind farms and wave and tidal energy conversion devices.

The research highlights the capacity for marine renewable energy devices to boost local biodiversity and benefit the wider marine environment. Man-made structures on the sea bed attract many marine organisms and sometimes become ‘artifical reefs’, for example, supporting a wide variety of fish. The study also points out that such devices could have negative environmental impacts, resulting from habitat loss, collision risks, noise and electromagnetic fields. (more…)

Possibly Related Posts:



Satellites and Submarines Give the Skinny on Sea Ice Thickness

Changes to sea ice influence the Arctic's local weather, climate and ecosystems -- and also polar bears, seen here from an icebreaking ship that passed though the Northwest Passage this summer during an eight-day series of meetings to discuss Arctic science. (Ronald Kwok/NASA)

Changes to sea ice influence the Arctic's local weather, climate and ecosystems -- and also polar bears, seen here from an icebreaking ship that passed though the Northwest Passage this summer during an eight-day series of meetings to discuss Arctic science. (Ronald Kwok/NASA)

This summer, a group of scientists and students — as well as a Canadian senator, a writer, and a filmmaker — set out from Resolute Bay, Canada, on the icebreaker Louis S. St-Laurent. They were headed through the Northwest Passage, but instead of opening shipping lanes in the ice, they had gathered to open up new lines of thinking on Arctic science.

Among the participants in the shipboard workshop (hosted by Fisheries and Oceans Canada) was Ron Kwok of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. Kwok has long provided checkups on the health of Arctic sea ice — the frozen sea water floating within the Arctic Ocean basin. He also knows that some important clues about ice changes can’t be seen from a ship.

While satellites provide accurate and expansive coverage of ice in the Arctic Ocean, the records are relatively new. Satellites have only monitored sea ice extent since 1973. NASA’s Ice, Cloud, and land Elevation Satellite (ICESat) has been on the task since 2003, allowing researchers to estimate ice thickness as well.

To extend the record, Kwok and Drew Rothrock of the University of Washington, Seattle, recently combined the high spatial coverage from satellites with a longer record from Cold War submarines to piece together a history of ice thickness that spans close to 50 years. (more…)

Possibly Related Posts:



Possible Geoengineering Responses to Climate Emergencies

A schematic representation of various geoengineering and carbon storage proposals. (Diagram by Kathleen Smith/LLNL)

A schematic representation of various geoengineering and carbon storage proposals. (Diagram by Kathleen Smith/LLNL)

The future of the Earth could rest on potentially dangerous and unproven geoengineering technologies unless emissions of carbon dioxide can be greatly reduced, a new study has found.

The report (published September 1, by the Royal Society, the UK’s national academy of science) found that unless future efforts to reduce greenhouse gas emissions are much more successful than they have been so far, additional action in the form of geoengineering will be necessary to cool the planet. However, the report identified major uncertainties regarding the effectiveness, costs, and environmental impacts of geoengineering technologies.

“Reducing our greenhouse gas emissions is more important than ever,” said coauthor Ken Caldeira of the Carnegie Institution’s Department of Global Ecology, “but even with our best efforts, the Earth is likely to continue warming throughout this century due to inertia in the climate system. Cutting emissions can reduce but cannot eliminate the risk of a climate emergency.” Possible climate emergencies include rapid collapse of the Greenland ice sheet into the sea causing major sea level rise, a shift in rainfall patterns causing massive global crop failures, or melting Arctic permafrost causing catastrophic release of the powerful greenhouse gas methane. (more…)

Possibly Related Posts:



Antarctic Glacier Thinning at Alarming Rate

British Antarctic Survey fieldcamp on Pine Island Glacier.

British Antarctic Survey fieldcamp on Pine Island Glacier.

The thinning of a gigantic glacier in Antarctica is accelerating, scientists warned today.

The Pine Island Glacier in West Antarctica, which is around twice the size of Scotland, is losing ice four times as fast as it was a decade years ago.

The research, published in the journal Geophysical Research Letters, also reveals that ice thinning is now occurring much further inland. At this rate scientists estimate that the main section of the glacier will have disappeared in just 100 years, six times sooner than was previously thought.

The Pine Island Glacier is located within the most inaccessible area of Antarctica – over 1000 km from the nearest research base – and was for many years overlooked. Now, scientists have been able to track the glacier’s development using continuous satellite measurements over the past 15 years. (more…)

Possibly Related Posts:



Changes in Net Flow of Ocean Heat Correlate with Past Climate Anomalies

sea-91Physicists at the University of Rochester have combed through data from satellites and ocean buoys and found evidence that in the last 50 years, the net flow of heat into and out of the oceans has changed direction three times.

These shifts in the balance of heat absorbed from the sun and radiated from the oceans correlate well with past anomalies that have been associated with abrupt shifts in the earth’s climate, say the researchers. These anomalies include changes in normal storm intensities, unusual land temperatures, and a large drop in salmon populations along the western United States. (more…)

Possibly Related Posts:



Proof That Hurricane Seasons Are More Active

This is a sediment core sample collected in a laguna along the Florida Panhandle. (Credit: Jon Woodruff)

This is a sediment core sample collected in a laguna along the Florida Panhandle. (Credit: Jon Woodruff)

For many Americans who live on the Atlantic coast, Andrew, Ivan and Katrina are more than just names–they are reminders of the devastating impact of cyclonic activity in the region during hurricane season. If it seems like hurricane seasons have been more active in recent years, you’re on to something. According to a paper published in the August 13 issue of Nature, the frequency and strength of these powerful storms has grown in recent decades.

“We are at levels now that are about as high as anything we have seen in the past 1,000 years,” said Michael Mann, director of the Earth System Science Center at Pennsylvania State University and the lead author of the paper. Mann and his collaborators, Jeffrey P. Donnelly of the Woods Hole Oceanographic Institution, Jonathan D. Woodruff of the University of Massachusetts and Zhihua Zhang of Pennsylvania State University examined sediment samples from across the North Atlantic coast and statistical models of historic hurricane activities. (more…)

Possibly Related Posts:



Détente on The Ocean Leads to New Hope for Fisheries

"The good news is that the pressure on the ecosystem is decreasing overall in half of the ten systems we have detailed data for,” says Dr. Boris Worm. (Photo Credit: Nick Pearce)

"The good news is that the pressure on the ecosystem is decreasing overall in half of the ten systems we have detailed data for,” says Dr. Boris Worm. (Photo Credit: Nick Pearce)

It was like Superman calling out Batman – fisheries scientist Ray Hilborn publicly criticizing the findings published by Dalhousie marine ecologist Boris Worm in 2006 suggesting the world’s oceans could run out of fish by 2048 if overfishing was allowed to continue. In questioning Dr. Worm’s projections, Dr. Hilborn, of the University of Washington, set off a media and scientific frenzy wondering how two of the most respected experts in their respective fields could be oceans apart in their views.

During such a public debate it would be hard to imagine a quick reconciliation between the two, but when they met during a call-in show on National Public Radio, that’s exactly what happened. “Through our discussions we realized we were actually not that far apart,” says Dr. Worm. “We became curious to see if we could find more common ground and whether this could bring those two disciplines closer together.” (more…)

Possibly Related Posts:



Science Adopts a New Definition of Seawater

This instrument deployed from a research vessel measures temperature and salinity in the ocean. Variations in salinity and heat influence ocean currents and measuring those variations is central to quantifying the ocean's role in climate change. (CSIRO)

This instrument deployed from a research vessel measures temperature and salinity in the ocean. Variations in salinity and heat influence ocean currents and measuring those variations is central to quantifying the ocean's role in climate change. (CSIRO)

In Paris late last month the General Assembly of UNESCO’s Intergovernmental Oceanographic Commission (IOC) accepted the case for the introduction of a new international thermodynamic description of seawater, cast in terms of a new salinity variable called Absolute Salinity.

Hobart-based CSIRO Wealth from Oceans Flagship scientist, Dr Trevor McDougall, made the case during his presentation of the Bruun Memorial Lecture to the Paris meeting.

“Scientists will now have an accurate measure of the heat content of seawater for inclusion in ocean models and climate projections,” Dr McDougall says.

“Variations in salinity and heat influence ocean currents and measuring those variations are central to quantifying the ocean’s role in climate change. The new values for salinity, density and heat content should be in widespread use within 18 months.” (more…)

Possibly Related Posts:



Sea-level Rise May Pose Greatest Threat to Northeast US, Canada

An aerial view of Long Island shows its low-lying shores, vulnerable to sea-level rise effects. (New York State Department of Environmental Conservation)

An aerial view of Long Island shows its low-lying shores, vulnerable to sea-level rise effects. (New York State Department of Environmental Conservation)

The melting of the Greenland Ice Sheet this century may drive more water than previously thought toward the already threatened coastlines of New York, Boston, Halifax and other cities in the northeastern United States and Canada, according to new research.

Results of the study are being published this week in Geophysical Research Letters. They suggest that moderate to high rates of ice melt from Greenland may shift ocean circulation by about 2100, causing sea levels off the northeast coast of North America to rise by about 30 to 51 centimeters (12 to 20 inches) more than other coastal areas.

The research builds on recent reports that have found that sea level rise could adversely affect North America, and its findings suggest that the situation is even more urgent than previously believed. (more…)

Possibly Related Posts:



Climate Change May Impact Circulation of World’s Oceans

A seaglider is prepared for deployment in Davis Strait by Avery Snyder and Adam Huxtable, field engineers with the University of Washington's Applied Physics Laboratory. (Applied Physics Laboratory/U. of Washington)

A seaglider is prepared for deployment in Davis Strait by Avery Snyder and Adam Huxtable, field engineers with the University of Washington's Applied Physics Laboratory. (Applied Physics Laboratory/U. of Washington)

The University of Washington has surpassed its 2-year-old world record for operating a glider under the ice, this time by successfully operating one of its seagliders for six months as it made round trips hundreds of miles in length under the ice at Davis Strait.

The result contributes to the longest continuous measurement of fresh water exiting the Arctic through the Canadian Arctic Archipelago and Davis Strait and into the Labrador Sea.

Scientists worry that climate change may increase the amount of fresh water so much that it impacts the formation of very dense water in the Labrador Sea. That dense, cold water is a critical component driving the circulation of the world’s oceans, according to Craig Lee, a principal oceanographer with the UW’s Applied Physics Laboratory. Lee and senior oceanographer Jason Gobat lead the group developing the under-ice seaglider. (more…)

Possibly Related Posts:



Recent Atlantic Ocean Warming Trend Tied to Reductions in Airborne Dust

Dusty years predict mild hurricane seasons, while years with low dust activity — including 2004 and 2005 — have been linked to stronger and more frequent hurricanes.

Dusty years predict mild hurricane seasons, while years with low dust activity — including 2004 and 2005 — have been linked to stronger and more frequent hurricanes.

The recent warming trend in the Atlantic Ocean is largely due to reductions in airborne dust and volcanic emissions during the past 30 years, according to a new study.

Since 1980, the tropical North Atlantic has been warming by an average of a quarter-degree Celsius (a half-degree Fahrenheit) per decade. Though this number sounds small, it can translate to big impacts on hurricanes, which thrive on warmer water, says Amato Evan, a researcher with the University of Wisconsin-Madison’s Cooperative Institute for Meteorological Satellite Studies and lead author of the new study. For example, the ocean temperature difference between 1994, a quiet hurricane year, and 2005’s record-breaking year of storms, was just one degree Fahrenheit. (more…)

Possibly Related Posts: