 |
|
1-888-632-5353
M-F 8 AM - 9 PM EST
|
|
is Searching for
Plans in ZIP Code
|
Sorry, that ZIP code
was not found.
Try Again
|
|
|
is Searching for
Dentist in ZIP Code
|
|
|
you are here: DentalPlans.com > Dental Health Articles > HealthnewsDigest.com > Global Warming Our Best Guess is Likely Wrong
| |
|
|
|
Updated: 7/14/2009 3:00:27 PM |
|
|
(HealthNewsDigest.com) - HOUSTON - No one knows exactly how much Earth's climate will warm due to carbon emissions, but a new study this week suggests scientists' best predictions about global warming might be incorrect.
The study, which appears in Nature Geoscience, found that climate models explain only about half of the heating that occurred during a well-documented period of rapid global warming in Earth's ancient past. The study, which was published online today, contains an analysis of published records from a period of rapid climatic warming about 55 million years ago known as the Palaeocene-Eocene thermal maximum, or PETM.
"In a nutshell, theoretical models cannot explain what we observe in the geological record," said oceanographer Gerald Dickens, a co-author of the study and professor of Earth science at Rice University. "There appears to be something fundamentally wrong with the way temperature and carbon are linked in climate models."
During the PETM, for reasons that are still unknown, the amount of carbon in Earth's atmosphere rose rapidly. For this reason, the PETM, which has been identified in hundreds of sediment core samples worldwide, is probably the best ancient climate analogue for present-day Earth.
In addition to rapidly rising levels of atmospheric carbon, global surface temperatures rose dramatically during the PETM. Average temperatures worldwide rose by about 7 degrees Celsius -- about 13 degrees Fahrenheit -- in the relatively short geological span of about 10,000 years.
Many of the findings come from studies of core samples drilled from the deep seafloor over the past two decades. When oceanographers study these samples, they can see changes in the carbon cycle during the PETM.
"You go along a core and everything's the same, the same, the same, and then suddenly you pass this time line and the carbon chemistry is completely different," Dickens said. "This has been documented time and again at sites all over the world."
Based on findings related to oceanic acidity levels during the PETM and on calculations about the cycling of carbon among the oceans, air, plants and soil, Dickens and co-authors Richard Zeebe of the University of Hawaii and James Zachos of the University of California-Santa Cruz determined that the level of carbon dioxide in the atmosphere increased by about 70 percent during the PETM.
That's significant because it does not represent a doubling of atmospheric carbon dioxide. Since the start of the industrial revolution, carbon dioxide levels are believed to have risen by about one-third, largely due to the burning of fossil fuels. If present rates of fossil-fuel consumption continue, the doubling of carbon dioxide from fossil fuels will occur sometime within the next century or two.
Doubling of atmospheric carbon dioxide is an oft-talked-about threshold, and today's climate models include accepted values for the climate's sensitivity to doubling. Using these accepted values and the PETM carbon data, the researchers found that the models could only explain about half of the warming that Earth experienced 55 million years ago.
The conclusion, Dickens said, is that something other than carbon dioxide caused much of the heating during the PETM. "Some feedback loop or other processes that aren't accounted for in these models -- the same ones used by the IPCC for current best estimates of 21st Century warming -- caused a substantial portion of the warming that occurred during the PETM."
To see the complete study, visit http://www.nature.com/ngeo/journal/vaop/ncurrent/abs/ngeo578.html
Subscribe to our FREE Ezine and be eligible for Health News, discounted products/services and coupons related to your Health. We publish 24/7.
HealthNewsDigest.com
Read Original Article
© 2009 HealthnewsDigest.com
|
|
|
|
|
|
|
|
The materials and articles published on DentalPlans.com are for informational purposes only. Although DentalPlans.com strives to be accurate and complete, the information is provided without liability for errors. DentalPlans.com does not warrant the accuracy or completeness of the information, text graphics, links, or other items contained on DentalPlans.com.
DentalPlans.com expressly disclaims liability for errors or omissions in these materials and DentalPlans.com makes no commitment to update the information on DentalPlans.com.
DentalPlans.com expressly disclaims all liability for the use or interpretation by others of information on DentalPlans.com. Decisions based on information contained on DentalPlans.com are the sole responsibility of the visitors, and visitors agree to hold DentalPlans.com and its Affiliates harmless against any claims for damages arising from decisions visitors make on such information.
Nothing on DentalPlans.com constitutes medical advice or other forms of advice. DentalPlans.com assumes no responsibility for material created or published by third parties linked to DentalPlans.com with or without DentalPlans.coms knowledge.
|
|
| |
|
|
The DENTALPLANS.COM website is administered by DENTALPLANS.COM, INC., a licensed Florida Discount Medical Plan Organization, 8100 S.W. 10th Street Suite #2000, Plantation, FL 33324. Plans and Programs offered by DentalPlans.com are not health insurance policies. Plans and Programs offered by DentalPlans.com provide discounts at certain health care providers for medical services. Plans and Programs offered by DentalPlans.com do not make payments directly to the providers of medical services. The Plan or Program member is obligated to pay for all health care services but will receive a discount from those health care providers who have contracted with the Plan, Program or discount plan organization.
|
Special promotions including but not limited to additional months free and Membership Rewards® points from American Express are not available to California residents.
© 1999-2011 DentalPlans.com, Inc. All Rights Reserved. Patents Pending. Blue Cross and Blue Shield of Florida is an Independent Licensee of the Blue Cross and Blue Shield Association. |
 
|
|
| |
|  |