Science Current Events | Science News | Brightsurf.com
 
Email a Friend Send to a friend
Printer Friendly Print World to be even hotter by century's end
Slashdot It! Slashdot World to be even hotter by century's end
Submit to Reddit Submit World to be even hotter by century's end to Reddit
Reading: World to be even hotter by century's endTwitter This Reading: World to be even hotter by century's endTwitter World to be even hotter by century's end
Add to Facebook Add World to be even hotter by century's end to Facebook

World to be even hotter by century's end

May 25, 2006

BERKELEY - If Earth's past cycles of warming and cooling are any indication, temperatures by the end of the century will be even hotter than current climate models predict, according to a report by University of California, Berkeley, researchers.

The scientists based their conclusion on a study of Antarctic ice cores containing a 360,000-year record of global temperature and levels of carbon dioxide and methane-two of the major greenhouse gases implicated in global warming. They found that during periods of warming, greenhouse gas levels rose and created significantly higher temperatures than would be expected solely from the increased intensity of sunlight that triggered these warm periods.




Though the ice core data do not point to specific processes that amplify the warming, the researchers suspect that it is due to warmer soils and oceans giving off more CO2 and methane, which add to the greenhouse effect of CO2 from fossil fuel burning and other human activities.

Thus, while current models predict temperature increases of 1.5 to 4.5 degrees Celsius (2.7 to 8.1 degrees Fahrenheit) from a doubling of atmospheric carbon dioxide levels, the natural processes injecting more CO2 into the atmosphere will lead to temperature increases of 1.6 to 6 degrees Celsius (2.9 to 10.8 degrees Fahrenheit), with the higher temperatures more likely, the researchers said.

"We are underestimating the magnitude of warming because we are ignoring the extra carbon dioxide dumped into the atmosphere because of warming," said John Harte, UC Berkeley professor of energy and resources and of environmental science, policy & management. "Warming gets an extra kick from CO2 feedback."

"The warming caused by our release of CO2 triggers changes in the Earth system that lead to release of more CO2 to the atmosphere," added co-author Margaret Torn, a UC Berkeley adjunct associate professor of energy and resources and staff scientist at Lawrence Berkeley National Laboratory. "If that is the case, then every bit of CO2 release now is actually committing us to a larger CO2 change in the atmosphere."

The result, Harte and Torn conclude in their paper, is "that the upper value of warming that is projected for the end of the 21st century, 5.8°C [10.4°F], could be increased to 7.7°C [13.9°F], or nearly 2°C additional warming."

The report is scheduled for publication in the May 26 issue of Geophysical Research Letters. That issue also will contain an article that looks at the same effect over a shorter time scale, confirming the amplification reported by Harte and Torn and suggesting that it may be even greater.

Current climate models, called General Circulation Models, start from fundamental physical processes to calculate a probable temperature increase based on likely atmospheric carbon dioxide levels, typically a doubling of today's CO2 concentration. These models also include feedback mechanisms that boost or moderate warming, such as the increased heat absorption expected when highly reflective ice sheets and glaciers melt; or the effect of more atmospheric water vapor on the formation of clouds, which both reflect sunlight and insulate the Earth.

But models are only now beginning to take into account the extra carbon dioxide and methane injected into the atmosphere as global temperatures increase. Though this is expected because warmer soils decompose faster, releasing more CO2, and because warmer oceans outgas more CO2, scientists have yet to quantify the full impact of these processes.

"Without a mechanism, people feel uncomfortable putting these processes in a model. I think that's a big mistake," Harte said.

Luckily, it's possible to estimate the effect of CO2 feedback by looking at how the Earth responded to past cycles of warming and cooling, which were caused by natural variations in the strength of sunlight hitting Earth, rather than by human production of greenhouse gases. Ice cores drilled in the Vostok ice sheet in 1998 and 1999 by Russia, France and the United States span nearly 420,000 years and carry information about four major climate cycles and many smaller temperature swings. In 1999, scientists measured CO2 and methane levels from gas trapped in bubbles in the ice, and have estimated global temperature based on oxygen isotope and deuterium ratios. UC Berkeley's Kurt Cuffey, professor of geography and earth and planetary science, updated these measurements in 2001.

Climate scientists immediately saw that the ice core data imply a strong positive feedback to global CO2 and methane levels, but how much this impacted warming trends was unclear.

Harte, a physicist by training, and Torn devised a way to use these data and current global climate models to estimate the effect of increased CO2 entering the atmosphere as a result of warming, called the "gain," analogous to the gain of an electronic amplifier-the factor by which output power increases. From Cuffey's data, Harte and Torn were able to extract the effect of temperature on CO2 and methane levels. They calculated the reverse-the effect of CO2 and methane levels on temperature, or the so-called climate sensitivity-from climate models, using a number consistent with a new estimate published in the April 20 issue of Nature.

Harte and Torn added the resultant gains from CO2 and methane to the gain already known for other climate feedbacks, in particular the largest source, increased atmospheric water vapor, to get a total gain that they used to calculate the temperature increase that would result from a doubling of current CO2 levels.

Both researchers emphasize that the large temperature range they predict-1.6 to 6 degrees Celsius-does not mean that we have an equal chance of ending up with less warming as with greater warming. In other words, it doesn't mean that the uncertainties are symmetric about an average increase of 3.8°C.

"People see this uncertainty and think that we have an equal probability of dodging a bullet as catching it. That is a fallacy," Torn said.

"By giving the appearance of symmetric feedback, people have an excuse to say, 'Maybe we don't have to worry so much,'" Harte said. "But while there are uncertainties in the feedbacks, all the major feedbacks are positive, meaning they would increase warming, and we know of no significant negative feedbacks that would slow warming."

While Harte acknowledges that the future may not look like past periods of global warming, "in the absence of contradictory evidence, we have to assume the future will respond like the past."

"Whatever the mechanisms that cause temperature to create a change in CO2 and methane, they are repeatable again and again and again over many cooling and warming cycles. So, although the world is different today than it was then, we don't have a basis for ignoring them," Torn added.

Harte has been conducting studies on experimental plots in the Rocky Mountains that would quantify the effect of warmer temperatures on soil carbon. He and his colleagues found that artificially heated plots lost significant soil carbon to the atmosphere as CO2, compared to control plots. Thus, he said, the effect of heating on the carbon cycle in his plots is to generate a positive feedback, though he noted that this might be a short-term effect. The long term effect, however, is unknown, as is the effect of warming in other habitats.

"We need to know the effect of warmer temperatures in all different habitats, not just temperate Rocky Mountain forests but also the tropics and European boreal forests and Eastern U.S. deciduous forests and savanna and prairie. There are huge data gaps," he said.

Torn noted, however, that humans are the biggest unknown.

"To predict the future, you have to guess how much CO2 levels will go up. That depends on the biggest uncertainty of all-what humans decide to do. Do we get smart and prevent CO2 emissions? Do we continue with business as usual? Or will we end up somewhere in between?"

The work was supported by the U.S. Department of Energy's Climate Change Research Division and by the National Science Foundation.

University of California, Berkeley





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.
Lymphoma   Solar Wind   Mercury Emissions   Carbon Footprint   Hibernation   Vascular Disease   Tumor Cells   Thyroid Cancer   Microscopy   Psychotherapy   Acute Lymphoblastic Leukemia   Shopping   Birth Weight   Omega-3 Fatty Acids   Walking   Leukemia   Neurofibromatosis   Miscarriage   Cocaine   Polyphenols   Climate Warming   Medulloblastoma   Heart Rhythm   Pulmonary Hypertension   OCD  
Related Climate Models Current Events and Climate Models News Articles Climate Models Current Events and Climate Models News RSS Climate Models Current Events and Climate Models News RSS
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.

Berkeley Lab Scientists Contribute to Major New Report Describing Climate Change Impacts on the U.S.
Two researchers at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab), Evan Mills and Michael Wehner, contributed to the analysis of the effects of climate change on all regions of the United States, described in a major report released today by the multi-agency U.S. Global Change Research Program.

A new measure of global warming from carbon emissions
Damon Matthews, a professor in Concordia University's Department of Geography, Planning and the Environment has found a direct relationship between carbon dioxide emissions and global warming.

Breakthrough made in assessing marine phytoplankton health
Researchers from Oregon State University, NASA and other organizations said today that they have succeeded for the first time in measuring the physiology of marine phytoplankton through satellite measurements of its fluorescence - an accomplishment that had been elusive for years.

Glacial advances
The vast majority of the world's glaciers are retreating as the planet gets warmer. But a few, including glaciers south of the equator in South America and New Zealand, are inching forward.

Climate change to spur rapid shifts in wildfire hotspots
Climate change will bring about major shifts in worldwide fire patterns, and those changes are coming fast.

New theory on largest known mass extinction in the history of the earth
Did volatile halogenated gases from giant salt lakes at the end of the Permian Age lead to a mass extinction of species?

Sea level rise due to global warming poses threat to New York City
Global warming is expected to cause the sea level along the northeastern U.S. coast to rise almost twice as fast as global sea levels during this century, putting New York City at greater risk for damage from hurricanes and winter storm surge, according to a new study led by a Florida State University researcher.

The Agulhas Current, in the southern hemisphere, may influence climate in Europe
Her PhD thesis "Surface and Deep Circulation off South Africa: Agulhas Leakage Influence on the Meridional Overturning Circulation During the Last 345 kyr" presented data on a major ocean current in the southern hemisphere, the Agulhas Current, which transports warm waters from the tropical Indian Ocean to the southern tip of Africa.

Eugene-Springfield face Upper Willamette climate threats
Effects of climate change projected this century for Oregon's Upper Willamette River Basin, including Eugene-Springfield, will threaten water supplies, buildings, transportation systems, human health, forests, and fish and wildlife, according to a report produced by the University of Oregon's Climate Leadership Initiative and the National Center for Conservation Science & Policy.
More Climate Models Current Events and Climate Models News Articles
Introduction To Three-dimensional Climate Modeling

Introduction To Three-dimensional Climate Modeling
by Warren M. Washington; Claire L. Parkinson (Author)

This book provides an introduction to the development of three-dimensional climate models, including their four major components: atmosphere, ocean, land/vegetation, and sea ice. The fundamental processes in each component and the interactions among them are explained using basic scientific principles, and elements of the numerical methods used in solving the model equations are also provided. The authors show how the theory and models grew historically and how well they are able to account for known aspects of the climate system. This book is written so that a reader who is only vaguely aware of climate models will be able to gain an understanding of what the models are attempting to simulate, how the models are constructed, what the models have succeeded in simulating, and how the...

Economic Models of Climate Change: A Critique

Economic Models of Climate Change: A Critique
by Palgrave Macmillan

The climate policy debate has been dominated by economic estimates of the costs of policies to reduce greenhouse gas emissions. Yet the models used to derive those estimates are based on assumptions that have largely gone untested. The conventional approach embodies structural features that rule out alternative market outcomes. In addition, the distribution of "climate rights" is crucial to determining the economic affects of various policies. Bringing these considerations to the forefront shows how domestic and international policy solutions might be found.


Climate Control Series Glasses, model: AIRRAGE, Lens Tint / Frame: Polarized Blue Mirror/Gloss Blac

Climate Control Series Glasses, model: AIRRAGE, Lens Tint / Frame: Polarized Blue Mirror/Gloss Blac
by Wiley X

Climate Control Series Glasses, model: AIRRAGE, Lens Tint / Frame: Polarized Blue Mirror/Gloss BlackPatented Removable Facial Cavity Seal Blocks Out Wind, Debris & Peripheral Light. Exceeds ANSI Z87.1-2003 High Velocity Impact Safety & Optical Standards. Fits Head Sizes: S - M Includes the following, Removable Facial Cavity Seal (695G) , Soft Case (DU63) , T-Peg Elastic Strap (XLE) , Leash Cord (EH-492-1) , Cleaning Cloth (A425) Designed For Smaller Faces Exceeds Ansi Z87.1-2003 High Velocity Impact Safety & Optical StandardsProduct photo may not exactly match the product offered for sale. Please refer to the product description.

  Amoena Breast Form - Model 458 (3)

The Amoena 458 Tria Light Breast Form features a patented, two-part removable Climate Pad (048) that has a soft gel layer that absorbs body heat from the chest wall and also has a soft fabric layer that wicks moisture away from the chest wall. Included with the post-mastectomy form are two 048 Climate Pads and a 30 mL bottle of Amoena Soft Cleanser. The Amoena 458 Post-Mastectomy Breast Form comes in a soft carrying case that is perfect for travel and storage. The Amoena 458 Form is the newest breast form with the Climate Technology and features: * Lightweight silicone makes this form 25% lighter than a comparable standard silicone form * Optimally equalized temperature with the innovative Amoena Climate pad between the breast form and the chest wall * Skin feels pleasantly dry due...

20X25 MERV16 HEALTH CLIMATE

20X25 MERV16 HEALTH CLIMATE
by Lennox

Highest rated filter available for residential systems MERV 16 GENUINE OEM Lennox Part# X6675 Interchangeable with Honeywell FC100A1037 or FC200E1037 MERV 16

HAI 2 Stage Heat/Cool Thermostat Model RC-122B

HAI 2 Stage Heat/Cool Thermostat Model RC-122B
by HAI

Two Stage heating and cooling systems (Not heat pumps) 2 stage heat, 2 stage cool Energy Efficient Control of second stage (EEC can be turned off if not desired) Automatic anticipator Use for Forced Air systems with two speed furnace, Two Speed air conditioner, Two Stage furnace and/or two stage air conditioner, electric, gas, oil or other fuel. All Thermostats Models Have: Auto changeover (will switch from heat to cool automatically) Programmable (if used stand alone, thermostat can be programmed for weekdays, Saturday and Sunday - 4 times per day) High and Low setting limits Outdoor temperature display (when connected to Omni, OmniPro or other system) Time display - time is displayed and is set automatically when connected to Omni, OmniPro or other system Filter reminder -...

Economic Models of Climate Change: A Critique

Economic Models of Climate Change: A Critique
by Stephen J. De Canio (Author)

The climate policy debate has been dominated by economic estimates of the costs of policies to reduce greenhouse gas emissions. Yet the models used to derive those estimates are based on assumptions that have largely gone untested. The conventional approach embodies structural features that rule out alternative market outcomes. In addition, the distribution of "climate rights" is crucial to determining the economic affects of various policies. Bringing these considerations to the forefront shows how domestic and international policy solutions might be found.


  Climate Change
by Saka Karakuri

A penguin attempts to escape the thawing tundra! Turn the crank and the penguin helplessly repeats his attempts to lift-off. Sadly, our darkly humorous penguin is not equiped to fly. Paper Animations by Saka Karakuri: These are original Japanese karakuri or "trick mechanism" by Keisuke Saka, one of the worlds best paper engineers. Saka's beautiful designs use only a few moving parts, yet produce elegant (and darkly humorous!) movement. Saka paper automata models are easy to do with complete illustrated instructions. Just cut out, fold, glue and assemble. Recommended for ages 12 and up (younger with adult help).

Stochastic Climate Theory: Models and Applications

Stochastic Climate Theory: Models and Applications
by Serguei G. Dobrovolski (Author)

The author describes the stochastic (probabilistic) approach to the study of changes in the climate system. Climatic data and theoretical considerations suggest that a large part of climatic variation/variability has a random nature and can be analyzed using the theory of stochastic processes. This work summarizes the results of processing existing records of climatic parameters as well as appropriate theories: from the theory of random processes (based on the results of Kolmogorov and Yaglom) and Hasselmann's "stochastic climate model theory" to recently obtained results.

Stochastic Climate Theory: Models and Applications

Stochastic Climate Theory: Models and Applications
by Springer

The author describes the stochastic (probabilistic) approach to the study of changes in the climate system. Climatic data and theoretical considerations suggest that a large part of climatic variation/variability has a random nature and can be analyzed using the theory of stochastic processes. This work summarizes the results of processing existing records of climatic parameters as well as appropriate theories: from the theory of random processes (based on the results of Kolmogorov and Yaglom) and Hasselmann's "stochastic climate model theory" to recently obtained results.

© 2009 BrightSurf.com