(Press-News.org) CORVALLIS, Ore. – A new study estimates that global sea levels will rise about 2.3 meters, or more than seven feet, over the next several thousand years for every degree (Celsius) the planet warms.
This international study is one of the first to combine analyses of four major contributors to potential sea level rise into a collective estimate, and compare it with evidence of past sea-level responses to global temperature changes.
Results of the study, funded primarily by the National Science Foundation and the German Federal Ministry of Education and Research, are being published this week in the Proceedings of the National Academy of Sciences.
"The study did not seek to estimate how much the planet will warm, or how rapidly sea levels will rise," noted Peter Clark, an Oregon State University paleoclimatologist and author on the PNAS article. "Instead, we were trying to pin down the 'sea-level commitment' of global warming on a multi-millennial time scale. In other words, how much would sea levels rise over long periods of time for each degree the planet warms and holds that warmth?"
"The simulations of future scenarios we ran from physical models were fairly consistent with evidence of sea-level rise from the past," Clark added. "Some 120,000 years ago, for example, it was 1-2 degrees warmer than it is now and sea levels were about five to nine meters higher. This is consistent with what our models say may happen in the future."
Scientists say the four major contributors to sea-level rise on a global scale will come from melting of glaciers, melting of the Greenland ice sheet, melting of the Antarctic ice sheet, and expansion of the ocean itself as it warms. Several past studies have examined each of these components, the authors say, but this is one of the first efforts at merging different analyses into a single projection.
The researchers ran hundreds of simulations through their models to calculate how the four areas would respond to warming, Clark said, and the response was mostly linear. The amount of melting and subsequent sea-level response was commensurate with the amount of warming. The exception, he said, was in Greenland, which seems to have a threshold at which the response can be amplified.
"As the ice sheet in Greenland melts over thousands of years and becomes lower, the temperature will increase because of the elevation loss," Clark said. "For every 1,000 meters of elevation loss, it warms about six degrees (Celsius). That elevation loss would accelerate the melting of the Greenland ice sheet."
In contrast, the Antarctic ice sheet is so cold that elevation loss won't affect it the same way. The melting of the ice sheet there comes primarily from the calving of icebergs, which float away and melt in warmer ocean waters, or the contact between the edges of the ice sheet and seawater.
In their paper, the authors note that sea-level rise in the past century has been dominated by the expansion of the ocean and melting of glaciers. The biggest contributions in the future may come from melting of the Greenland ice sheet, which could disappear entirely, and the Antarctic ice sheet, which will likely reach some kind of equilibrium with atmospheric temperatures and shrink significantly, but not disappear.
"Keep in mind that the sea level rise projected by these models of 2.3 meters per degree of warming is over thousands of years," emphasized Clark, who is a professor in Oregon State University's College of Earth, Ocean, and Atmospheric Sciences. "If it warms a degree in the next two years, sea levels won't necessarily rise immediately. The Earth has to warm and hold that increased temperature over time.
"However, carbon dioxide has a very long time scale and the amounts we've emitted into the atmosphere will stay up there for thousands of years," he added. "Even if we were to reduce emissions, the sea-level commitment of global warming will be significant."
INFORMATION: END
A pair of studies by a team of University of Notre Dame researchers led by Crislyn D'Souza-Schorey, professor of biological sciences, sheds light on a biological process which is activated across a vast range of malignancies.
Wnt proteins are a large family of proteins that active signaling pathways (a set of biological reactions in a cell) to control several vital steps in embryonic development. In adults, Wnt-mediated functions are frequently altered in many types of cancers and, specifically, within cell subpopulations that possess stem cell-like properties.
In ...
Two NASA spacecraft have provided the most comprehensive movie ever of a mysterious process at the heart of all explosions on the sun: magnetic reconnection. Magnetic reconnection happens when magnetic field lines come together, break apart and then exchange partners, snapping into new positions and releasing a jolt of magnetic energy. This process lies at the heart of giant explosions on the sun, such as solar flares and coronal mass ejections, which can fling radiation and particles across the solar system.
Scientists want to better understand this process so they ...
Researchers at Holland Bloorview Kids Rehabilitation Hospital have found that more than 25 percent of children with cerebral palsy seen by physicians have moderate to severe chronic pain, limiting their activity. Findings indicate that pediatricians should be aware of chronic pain in this group and try to identify and treat its underlying causes.
The study, led by Dr. Darcy Fehlings, Physician Director of the Child Development Program at Holland Bloorview and Clinician Senior Scientist at the Bloorview Research Institute, was published today in top health journal Pediatrics. ...
OAK BROOK, Ill. -- Excess fat around the belly has recently been identified as a risk factor for bone loss. Now, a new study has determined that excess liver and muscle fat also may be detrimental to bone.
The study, published online in the journal Radiology, found that obese people with higher levels of fat in their liver, muscle tissue and blood also have higher amounts of fat in their bone marrow, putting them at risk for osteoporosis.
"Obesity was once thought to be protective against bone loss," said study lead author Miriam A. Bredella, M.D., a radiologist at ...
Some strains of the avian H7N9 influenza that emerged in China this year have developed resistance to the only antiviral drugs available to treat the infection, but testing for antiviral resistance can give misleading results, helping hasten the spread of resistant strains.
The authors of a study published in mBio®, the online open-access journal of the American Society for Microbiology, characterized viruses taken from the first person known to be stricken with H7N9 influenza and found that 35% of those viruses are resistant to oseltamivir (commercially known as Tamiflu) ...
Standard toxicity testing is inadequate to assess the safety of a new technology with potential for creating pesticides and genetically modifying crops, according to a Forum article published in the August issue of BioScience. The authors of the article, Jonathan G. Lundgren and Jian J. Duan of the USDA Agricultural Research Service, argue that pesticides and insect-resistant crops based on RNA interference, now in exploratory development, may have to be tested under elaborate procedures that assess effects on animals' whole life cycles, rather than by methods that look ...
Whether you're reading the paper or thinking through your schedule for the day, chances are that you're hearing yourself speak even if you're not saying words out loud. This internal speech — the monologue you "hear" inside your head — is a ubiquitous but largely unexamined phenomenon. A new study looks at a possible brain mechanism that could explain how we hear this inner voice in the absence of actual sound.
In two experiments, researcher Mark Scott of the University of British Columbia found evidence that a brain signal called corollary discharge — a signal that helps ...
Tropical trees and hanging vines burst into flower, showering the ground below with bright blossoms. Temperature, rather than cloud cover, may be key to the timing of tropical flowering events according to research at two sites in the Smithsonian Institution Global Earth Observatory Network published online in Nature Climate Change.
Scientists discovered a significant increase in flower production—about 3 percent more flowers produced on average per year since 1987—on Barro Colorado Island's Forest Dynamics Plot in Panama.
"Barro Colorado Island was chosen for this study ...
A UCLA-led study of HIV-positive women who were sexually abused as children has found that the more severe their past trauma, the greater their improvement in an intervention program designed to ease their psychological suffering.
The study, conducted by researchers at UCLA's Collaborative Center for Culture, Trauma and Mental Health Disparities, suggests that such interventions should be tailored to individuals' experience and that a "one size fits all" approach may not be enough to successfully reduce women's depression, post-traumatic stress and anxiety symptoms. ...
Vitamin D influences many other physiological processes, including muscle function, cardiovascular homeostasis, nerve function, and immune response. Furthermore, accumulated evidence suggests that vitamin D also mediates the immune system response to infection. Infections are very common in patients from neurosurgical intensive care unit. A recent study published in the Neural Regeneration Research (Vol. 8, No. 16, 2013) detected serum vitamin D level in 15 patients with clinically suspected infection and 10 patients with confirmed infection, who came from neurosurgical ...
