 |
|
Study: Future snowmelt in West twice as early as expected; threatens ecosystems and water reserves
July 16, 2008According to a new study, global warming could lead to larger changes in snowmelt in the western United States than was previously thought, possibly increasing wildfire risk and creating new water management challenges for agriculture, ecosystems and urban populations.
Researchers, including a Purdue University professor of earth and atmospheric sciences, discovered that a critical surface temperature feedback is twice as strong as what had been projected by earlier studies.
The high-resolution climate model used by the team was better able to reproduce the complex topography of the western United States and capture details of the effect of snow cover on the climate system, as well as the historical record of runoff.
The findings will be published in an upcoming issue of Geophysical Research Letters and are now available online at the journal's Web site.
Noah Diffenbaugh, senior author of the paper and an associate professor of earth and atmospheric sciences at Purdue, said the influence of melting snow on regional climate is far greater than that of increased greenhouse gases alone.
"The heat trapping from elevated greenhouse gases triggers the warming, but the additional warming caused by the loss of snow is what really creates the big changes in surface runoff," said Diffenbaugh, who also is a member of Purdue's Climate Change Research Center. "Scientists have known about this general effect for years. The big surprise here is how much the complex topography plays a role, essentially doubling the threat to water resources in the West."
Sara A. Rauscher, visiting scientist at the Abdus Salam International Centre for Theoretical Physics in Trieste, Italy, and lead author on the paper, said the melting snow contributes to a feedback loop that accelerates warming.
"Because snow is more reflective than the ground or vegetation beneath it, it keeps the surface temperatures lower by reflecting energy from the sun," Rauscher said. "When snow melts or does not accumulate in the first place, more solar energy is absorbed by the ground, warming the surface. A feedback loop is created because the warmer ground then makes it more difficult for snow to accumulate and perpetuates the effect."
The amount and timing of the runoff from snowmelt is critical to the success of water management in the western United States. Water resources for the area are reliant on snow acting as a natural reservoir during the cold season that melts and releases water in the warm season.
Changes in this timing could create problems in meeting the increasing demand for water in large urban and agricultural areas during the hottest summer months, Diffenbaugh said.
"If the snow melts earlier or if it comes as rainfall instead, it would create a strain on infrastructure," he said. "The current system relies on water being stored in the mountains as snow. So earlier runoff could mean too much water for the reservoirs early in the year and not enough available later in the year."
Gregg M. Garfin, deputy director for science translation and outreach at the Institute for the Study of Planet Earth at the University of Arizona, said dry summers could lead to more severe wildfires and changes in the ecosystems of the West.
"Early snowmelt and warmer soil temperatures could result in further massive forest mortality and an increased risk of wildfire activity," Garfin said. "If these projections become reality, then the ecosystems of the northern and central Rockies will undergo dramatic changes with ramifications for wildlife habitat, fire potential, soil erosion and tourism."
The study suggests a substantial change in the runoff season, with the peak date more than two months earlier than today in some regions, Diffenbaugh said.
"During the past 50 years, the peak runoff time has moved 10 to 15 days earlier," he said. "It is not surprising that as we look to the future, the projected changes are much greater than the historical changes. The increase in greenhouse gas emissions has been relatively small for the past 50 years compared with where we are headed over the next several decades if substantial changes in energy technology and population growth do not occur."
The researchers also compared the climate model to historical records and found that it had a high level of agreement with historical data and observed trends.
"One of the most important contributions of this work is the remarkable agreement between the climate model and the observations of the recent past," Diffenbaugh said. "This agreement should increase confidence not only in these particular projections of future changes, but also of climate model projections in general."
Additional study co-authors are Jeremy S. Pal of Loyola Marymount University and Michael Benedetti of the University of North Carolina at Wilmington. The research was funded in part by grants from the National Science Foundation.
The Purdue Climate Change Research Center is affiliated with Purdue's Discovery Park. The center promotes and organizes research and education on global climate change and studies its impact on agriculture, natural ecosystems and society. It was established in 2004 to support Purdue in research and education on regional-scale climate change, its impacts and mitigation, and adaptation strategies. The center serves as a hub for a range of activities beyond scientific research, including teaching, public education and the development of public policy recommendations.
The high-resolution climate model simulations were conducted using computing resources in Purdue's Rosen Center for Advanced Computing. The Rosen Center is a research computing center named in memory of Saul Rosen, who served as director of Purdue's Computing Center from 1968-87 and helped establish Purdue as a pioneering academic institution in high-performance computing. The Rosen Center is a part of Information Technology at Purdue, which is responsible for planning and coordinating the central computing and telecommunications systems on the West Lafayette campus.
The Abdus Salam International Centre for Theoretical Physics was founded in 1964 by Nobel Laureate Abdus Salam. The center operates under a tripartite agreement among the Italian Government and two U.N. agencies, UNESCO and IAEA. Its mission is to foster advanced studies and research, especially in developing countries. While the name of the center reflects its beginnings, its activities today include geophysical and environmental sciences.
Purdue University
The findings will be published in an upcoming issue of Geophysical Research Letters and are now available online at the journal's Web site.
Noah Diffenbaugh, senior author of the paper and an associate professor of earth and atmospheric sciences at Purdue, said the influence of melting snow on regional climate is far greater than that of increased greenhouse gases alone.
"The heat trapping from elevated greenhouse gases triggers the warming, but the additional warming caused by the loss of snow is what really creates the big changes in surface runoff," said Diffenbaugh, who also is a member of Purdue's Climate Change Research Center. "Scientists have known about this general effect for years. The big surprise here is how much the complex topography plays a role, essentially doubling the threat to water resources in the West."
Sara A. Rauscher, visiting scientist at the Abdus Salam International Centre for Theoretical Physics in Trieste, Italy, and lead author on the paper, said the melting snow contributes to a feedback loop that accelerates warming.
"Because snow is more reflective than the ground or vegetation beneath it, it keeps the surface temperatures lower by reflecting energy from the sun," Rauscher said. "When snow melts or does not accumulate in the first place, more solar energy is absorbed by the ground, warming the surface. A feedback loop is created because the warmer ground then makes it more difficult for snow to accumulate and perpetuates the effect."
The amount and timing of the runoff from snowmelt is critical to the success of water management in the western United States. Water resources for the area are reliant on snow acting as a natural reservoir during the cold season that melts and releases water in the warm season.
Changes in this timing could create problems in meeting the increasing demand for water in large urban and agricultural areas during the hottest summer months, Diffenbaugh said.
"If the snow melts earlier or if it comes as rainfall instead, it would create a strain on infrastructure," he said. "The current system relies on water being stored in the mountains as snow. So earlier runoff could mean too much water for the reservoirs early in the year and not enough available later in the year."
Gregg M. Garfin, deputy director for science translation and outreach at the Institute for the Study of Planet Earth at the University of Arizona, said dry summers could lead to more severe wildfires and changes in the ecosystems of the West.
"Early snowmelt and warmer soil temperatures could result in further massive forest mortality and an increased risk of wildfire activity," Garfin said. "If these projections become reality, then the ecosystems of the northern and central Rockies will undergo dramatic changes with ramifications for wildlife habitat, fire potential, soil erosion and tourism."
The study suggests a substantial change in the runoff season, with the peak date more than two months earlier than today in some regions, Diffenbaugh said.
"During the past 50 years, the peak runoff time has moved 10 to 15 days earlier," he said. "It is not surprising that as we look to the future, the projected changes are much greater than the historical changes. The increase in greenhouse gas emissions has been relatively small for the past 50 years compared with where we are headed over the next several decades if substantial changes in energy technology and population growth do not occur."
The researchers also compared the climate model to historical records and found that it had a high level of agreement with historical data and observed trends.
"One of the most important contributions of this work is the remarkable agreement between the climate model and the observations of the recent past," Diffenbaugh said. "This agreement should increase confidence not only in these particular projections of future changes, but also of climate model projections in general."
Additional study co-authors are Jeremy S. Pal of Loyola Marymount University and Michael Benedetti of the University of North Carolina at Wilmington. The research was funded in part by grants from the National Science Foundation.
The Purdue Climate Change Research Center is affiliated with Purdue's Discovery Park. The center promotes and organizes research and education on global climate change and studies its impact on agriculture, natural ecosystems and society. It was established in 2004 to support Purdue in research and education on regional-scale climate change, its impacts and mitigation, and adaptation strategies. The center serves as a hub for a range of activities beyond scientific research, including teaching, public education and the development of public policy recommendations.
The high-resolution climate model simulations were conducted using computing resources in Purdue's Rosen Center for Advanced Computing. The Rosen Center is a research computing center named in memory of Saul Rosen, who served as director of Purdue's Computing Center from 1968-87 and helped establish Purdue as a pioneering academic institution in high-performance computing. The Rosen Center is a part of Information Technology at Purdue, which is responsible for planning and coordinating the central computing and telecommunications systems on the West Lafayette campus.
The Abdus Salam International Centre for Theoretical Physics was founded in 1964 by Nobel Laureate Abdus Salam. The center operates under a tripartite agreement among the Italian Government and two U.N. agencies, UNESCO and IAEA. Its mission is to foster advanced studies and research, especially in developing countries. While the name of the center reflects its beginnings, its activities today include geophysical and environmental sciences.
Purdue University
Climate Change Current Events and Climate Change News RSSGas from the past gives scientists new insights into climate and the oceans
In recent years, public discussion of climate change has included concerns that increased levels of carbon dioxide will contribute to global warming, which in turn may change the circulation in the earth's oceans, with potentially disastrous consequences.
Bays on US Gulf Coast vulnerable to flooding
The most comprehensive geological review ever undertaken of the upper U.S. Gulf Coast suggests that a combination of rising seas and dammed rivers could flood large swaths of wetlands this century in one or more bays from Alabama to Texas.
Thinking it through: Scientists call for policy to guide biofuels industry toward sustainability
As the United States and other nations commit to the path of biofuels production, a group of scientists is calling for sustainable practices in an industry that will, as MBL scientist Jerry Mellilo says, "reshape the Earth's landscape in a significant way."
Mandate for biofuels production requires science-based policy and global perspective
In his State of the Union Address on January 23, 2007, President Bush stated that, in order to substantially lower foreign oil imports, "We must increase the supply of alternative fuels, by setting a mandatory fuels standard to require 35 billion gallons of renewable and alternative fuels in 2017."
Arctic sea ice annual freeze-up underway
After reaching the second-lowest extent ever recorded last month, sea ice in the Arctic has begun to refreeze in the face of autumn temperatures, closing both the Northern Sea Route and the direct route through the Northwest Passage.
Algal biomonitor
A paper published in the current issue of the International Journal of Environment and Pollution, explains how a DNA test can be used to detect harmful algal blooms across the globe.
Canada's shores saved animals from devastating climate change
The shorelines of ancient Alberta, British Columbia and the Canadian Arctic were an important refuge for some of the world's earliest animals, most of which were wiped out by a mysterious global extinction event some 252 million years ago.
Shade trees can protect coffee crops
Sustainable farming that employs shade trees may improve crops' resistance to temperature and precipitation extremes that climate changes are expected to trigger.
Green coffee-growing practices buffer climate-change impacts
Chalk up another environmental benefit for shade-grown Latin American coffee: University of Michigan researchers say the technique will provide a buffer against the ravages of climate change in the coming decades.
Cranking up the volume-- Sounds travel farther underwater as world's oceans become more acidic
It is common knowledge that the world's oceans and atmosphere are warming as humans release more and more carbon dioxide into the Earth's atmosphere. However, fewer people realize that the chemistry of the oceans is also changing--seawater is becoming more acidic as carbon dioxide from the atmosphere dissolves in the oceans.
More Climate Change Current Events and Climate Change News Articles
 | The Rough Guide to Climate Change, 2nd Edition by Robert Henson The Rough Guide to Climate Change gives the complete picture of the single biggest issue facing the planet. Cutting a swathe through scientific research and political debate, this completely updated 2nd edition lays out the facts and assesses the options- global and personal- for dealing with the threat of a warming world. The guide looks at the evolution of our atmosphere over the last 4.5... |
 | Financing Education in a Climate of Change (10th Edition) by Vern Brimley, Rulon R. Garfield |
 | The Atlas of Climate Change: Mapping the World's Greatest Challenge (Atlas Of... (University of California Press)) by Kirstin Dow, Thomas Downing Today's headlines and recent events reflect the gravity of climate change. Heat waves, droughts, and floods are bringing death to vulnerable populations, destroying livelihoods, and driving people from their homes. Rigorous in its science and insightful in its message, this atlas examines the causes of climate change and considers its possible impact on subsistence, water resources, ecosystems,... |
 | What We Know About Climate Change (Boston Review Books) by Kerry Emanuel The vast majority of scientists agree that human activity has significantly increased greenhouse gases in the atmosphere—most dramatically since the 1970s. In February 2007 the Intergovernmental Panel on Climate Change found that global warming is "unequivocal" and that human-produced carbon dioxide and other greenhouse gases are chiefly to blame, to a certainty of more than 90 percent. Yet... |
 | Climate Change: What's Your Business Strategy? (Memo to the CEO) by Andrew J. Hoffman, John G. Woody Climate change is one of the most pressing challenges facing the world today. And increasingly, it's become a crucial business issue. How will you and your company respond?In Climate Change: What's Your Business Strategy? Andrew Hoffman and John Woody provide concise and reliable advice to help you answer this question. Drawing from their extensive experience working with organizations to address... |
 | The Science and Politics of Global Climate Change: A Guide to the Debate by Andrew E. Dessler, Edward A. Parson Climate variability has become the primary environmental concern of the 21st Century. Yet, despite the scientific community's warnings of the imminent dangers of global warming, politicians world-wide have failed to agree on what to do about this potentially devastating environmental problem. This introductory primer informs scientists, policy makers and the general public by clarifying the... |
 | Global Climate Change and U.S. Law This comprehensive, current examination of U.S. law as it relates to global climate change begins with a summary of the factual and scientific background of climate change based on governmental statistics and other official sources. Subsequent chapters address the international and national frameworks of climate change law, including the Kyoto Protocol, state programs affected in the absence of a... |
 | Economic Models of Climate Change: A Critique by Stephen J. De Canio 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... |
 | Climate Change in Prehistory: The End of the Reign of Chaos by William James Burroughs How did humankind deal with the extreme challenges of the last Ice Age? How have the relatively benign post-Ice Age conditions affected the evolution and spread of humanity across the globe? By setting our genetic history in the context of climate change during prehistory, the origin of many features of our modern world are identified and presented in this illuminating book. It reviews the... |
 | Climate Change: What It Means for Us, Our Children, and Our Grandchildren (American and Comparative Environmental Policy) Most of us are familiar with the terms climate change and global warming, but not too many of us understand the science behind them. We don't really understand how climate change will affect us, and for that reason we might not consider it as pressing a concern as, say, housing prices or the quality of local education. This book explains the scientific knowledge about global climate change... |
| © 2008 BrightSurf.com |