Science Current Events | Science News | Brightsurf.com
 
Email a Friend Send to a friend
Printer Friendly Print North Atlantic warming tied to natural variability; but global warming may be at play elsewhere
Slashdot It! Slashdot North Atlantic warming tied to natural variability; but global warming may be at play elsewhere
Submit to Reddit Submit North Atlantic warming tied to natural variability; but global warming may be at play elsewhere to Reddit
Reading: North Atlantic warming tied to natural variability; but global warming may be at play elsewhereTwitter This Reading: North Atlantic warming tied to natural variability; but global warming may be at play elsewhereTwitter North Atlantic warming tied to natural variability; but global warming may be at play elsewhere
Add to Facebook Add North Atlantic warming tied to natural variability; but global warming may be at play elsewhere to Facebook

North Atlantic warming tied to natural variability; but global warming may be at play elsewhere

January 04, 2008

DURHAM, N.C. - A Duke University-led analysis of available records shows that while the North Atlantic Ocean's surface waters warmed in the 50 years between 1950 and 2000, the change was not uniform. In fact, the subpolar regions cooled at the same time that subtropical and tropical waters warmed.

This striking pattern can be explained largely by the influence of a natural and cyclical wind circulation pattern called the North Atlantic Oscillation (NAO), wrote authors of a study published Thursday, Jan. 3, in Science Express, the online edition of the journal Science.




Winds that power the NAO are driven by atmospheric pressure differences between areas around Iceland and the Azores. "The winds have a tremendous impact on the underlying ocean," said Susan Lozier, a professor of physical oceanography at Duke's Nicholas School of the Environment and Earth Sciences who is the study's first author.

Other studies cited in the Science Express report suggest human-caused global warming may be affecting recent ocean heating trends. But Lozier and her coauthors found their data can't support that view for the North Atlantic. "It is premature to conclusively attribute these regional patterns of heat gain to greenhouse warming," they wrote.

"The take-home message is that the NAO produces strong natural variability," said Lozier in an interview. "The simplistic view of global warming is that everything forward in time will warm uniformly. But this very strong natural variability is superimposed on human-caused warming. So researchers will need to unravel that natural variability to get at the part humans are responsible for."

In research supported by the National Science Foundation in the United States and the Natural Environment Research Council in the United Kingdom, her international team analyzed 50 years of North Atlantic temperature records collected at the National Oceanic Data Center in Washington, D.C.

To piece together the mechanisms involved in the observed changes, their analysis employed an ocean circulation model that predicts how winds, evaporation, precipitation and the exchange of heat with the atmosphere influences the North Atlantic's heat content over time. They also compared those computer predictions to real observations "to test the model's skill," the authors wrote.

Her group's analysis showed that water in the sub-polar ocean -- roughly between 45 degrees North latitude and the Arctic Circle -- became cooler as the water directly exchanged heat with the air above it.

By contrast, NOA-driven winds served to "pile up" sun-warmed waters in parts of the subtropical and tropical North Atlantic south of 45 degrees, Lozier said. That retained and distributed heat at the surface while pushing underlying cooler water further down.

The group's computer model predicted warmer sea surfaces in the tropics and subtropics and colder readings within the sub-polar zone whenever the NAO is in an elevated state of activity. Such a high NAO has been the case during the years 1980 to 2000, the scientists reported.

"We suggest that the large-scale, decadal changes...associated with the NAO are primarily responsible for the ocean heat content changes in the North Atlantic over the past 50 years," the authors concluded.

However, the researchers also noted that this study should not be viewed in isolation. Given reported heat content gains in other oceans basins, and rising air temperatures, the authors surmised that other parts of the world's ocean systems may have taken up the excess heat produced by global warming.

"But in the North Atlantic, any anthropogenic (human-caused) warming would presently be masked by such strong natural variability," they wrote.

Duke University





Science News and Science Current Events Tag Cloud
This tag cloud is a visual representation of term frequencies of random science news topics with common terms grouped together and emphasized by their display size.
Methamphetamine   Smoking cessation   Marine Life   Mathematics   Smoking   Chronic inflammation   Comet Dust   Blood Vessel   Tumor Suppressor   Semiconductor   Sinkhole   Polycystic kidney disease   Oxygen   Gold Nanoparticles   Stratosphere   Water Molecules   Enzyme Inhibitor   Axons   Mental Disorder   Mass Extinction   Breast Cancer   Saturns Rings   Cholesterol   Irritable Bowel Syndrome   Heart Muscle  
Related Global Warming Current Events and Global Warming News Articles Global Warming Current Events and Global Warming News RSS Global Warming Current Events and Global Warming News RSS
Desert dust alters ecology of Colorado alpine meadows
Accelerated snowmelt--precipitated by desert dust blowing into the mountains--changes how alpine plants respond to seasonal climate cues that regulate their life cycles.

Your own private global warming
A group of researchers from the British Antarctic Survey have collected individuals from a wide range of species commonly found in Antarctic waters and subjected them to increasing levels of water temperature to learn how each species is prepared to cope with the conditions that they are likely to experience in the future.

Iowa State researchers contribute climate model to study that finds some winds decreasing
Declining wind speeds in parts of the United States could impact more than the wind power industry, say Iowa State University climate researchers.

Dry autumns and winters may lead to fewer tornadoes in the spring, says UGA researcher
Global warming will likely mean more unpredictable weather, scientists say, and a new study by researchers at the University of Georgia pins down, possibly for the first time, how drought conditions in an area's fall and winter may effect tornado activity the following spring.

Close relationship between past warming and sea-level rise
In a paper in Nature Geoscience, a team from the National Oceanography Centre, Southampton (NOCS), along with colleagues from Tübingen (Germany) and Bristol presents a novel continuous reconstruction of sea level fluctuations over the last 520 thousand years.

Corals face 'a stormy future'
As global warming whips up more powerful and frequent hurricanes and storms, the world's coral reefs face increased disruption to their ability to breed and recover from damage.

GEN reports on alternative feedstocks for ethanol production
Scientists say they are forging ahead in developing replacements for petrochemical fuels that will be cost-competitive and renewable while having a minimal impact on the environment, reports Genetic Engineering & Biotechnology News (GEN).

Ice Sheets Can Retreat
Modern glaciers, such as those making up the Greenland and Antarctic ice sheets, are capable of undergoing periods of rapid shrinkage or retreat, according to new findings by paleoclimatologists at the University at Buffalo.

New tracking approach will help protect polar bears
A new approach to tracking polar bears, developed by Queen's University researchers, will shed more light on the potentially endangered Arctic animal and help boost the economy of Canada's north.

Sudden collapse in ancient biodiversity: Was global warming the culprit?
Scientists have unearthed striking evidence for a sudden ancient collapse in plant biodiversity. A trove of 200 million-year-old fossil leaves collected in East Greenland tells the story, carrying its message across time to us today.
More Global Warming Current Events and Global Warming News Articles
The Great Global Warming Swindle (DVD)

The Great Global Warming Swindle (DVD)
Starring: Scientists, Economists, Politicians, Writers
Directed By: Martin Durkin



Unstoppable Global Warming: Every 1,500 Years, Updated and Expanded Edition

Unstoppable Global Warming: Every 1,500 Years, Updated and Expanded Edition
by S. Fred Singer (Author), Dennis T. Avery (Author)

In this New York Times bestseller, authors Singer and Avery present the compelling concept that global temperatures have been rising mostly or entirely because of a natural cycle. Using historic data from two millennia of recorded history combined with natural physical records, the authors argue that the 1,500 year solar-driven cycle that has always controlled the earth's climate remains the driving force in the current warming trend.

The Politically Incorrect Guide to Global Warming (and Environmentalism)

The Politically Incorrect Guide to Global Warming (and Environmentalism)
by Christopher C. Horner (Author)

This latest installment in the P.I.G. series provides a provocative, entertaining, and well-documented expose of some of the most shamelessly politicized pseudo-science we are likely to see in our relatively cool lifetimes.

Global Warming: A Scientific and Biblical Expose' of Climate Change

Global Warming: A Scientific and Biblical Expose' of Climate Change
Starring: Larry Vardiman, Calvin Beisner, Al Gore, Jason Lisle, Michael J. Oard
Directed By: Jason Beaupied,Ben Wilt Javier Pena



Global Warming: The Complete Briefing

Global Warming: The Complete Briefing
by John Houghton (Author)

John Houghton's market-leading textbook is now in full color and includes the latest IPCC findings, making it the definitive guide to climate change. Written for students across a wide range of disciplines, its simple, logical flow of ideas gives an invaluable grounding in the science and impacts of climate change and highlights the need for action on global warming. Is there evidence for climate changing due to human activities? How do we account for recent extremes of weather and climate? Can global electricity provision and transport ever be carbon free? Written by a leading figure at the forefront of action to confront humanity's most serious environmental problem, this undergraduate textbook comprehensively explores these and other issues, allowing students to think through the...

Global Warming: The Signs and the Science

Global Warming: The Signs and the Science
Starring: Global Warming-Signs & the Science

Studio: Pbs Release Date: 05/19/2009

The Politically Incorrect Guide to Global Warming

The Politically Incorrect Guide to Global Warming
by Regnery

This latest installment in the P.I.G. series provides a provocative, entertaining, and well-documented expose of some of the most shamelessly politicized pseudo-science we are likely to see in our relatively cool lifetimes.

Down-to-Earth Guide To Global Warming

Down-to-Earth Guide To Global Warming
by Laurie David and Cambria Gordon (Author)

Irreverent and entertaining, DOWN TO EARTH is filled with fact about global warming and its disastrous consequences, loads of photos and illustrations, as well as suggestions for how kids can help combat global warming in their homes, schools, and communities. Engagingly designed, DOWN TO EARTH will educate and empower, leaving readers with the knowledge they need to understand this problem and a sense of hope to inspire them into action.

National Geographic: Six Degrees Could Change the World

National Geographic: Six Degrees Could Change the World
Starring: Alec Baldwin
Directed By: Ron Bowman

In a special broadcast event, National Geographic explores the startling theory that Earths average temperature could rise six degrees Celsius by the year 2100. In this amazing and insightful documentary, National Geographic illustrates, one poignant degree at a time, the consequences of rising temperatures on Earth. Also, learn how existing technologies and remedies can help in the battle to dial back the global thermometer.

Climate Confusion: How Global Warming Hysteria Leads to Bad Science, Pandering Politicians and Misguided Policies that Hurt the Poor

Climate Confusion: How Global Warming Hysteria Leads to Bad Science, Pandering Politicians and Misguided Policies that Hurt the Poor
by Roy Spencer (Author)

The current frenzy over global warming has galvanized the public and cost taxpayers billons of dollars in federal expenditures for climate research. It has spawned Hollywood blockbusters and inspired major political movements. It has given a higher calling to celebrities and built a lucrative industry for scores of eager scientists. In short, ending climate change has become a national crusade.

And yet, despite this dominant and sprawling campaign, the facts behind global warming remain as confounding as ever.

In Climate Confusion, distinguished climatologist Dr. Roy Spencer observes that our obsession with global warming has only clouded the issue. Forsaking blindingly technical statistics and doomsday scenarios, Dr. Spencer explains in simple terms how the climate system...

© 2009 BrightSurf.com