tx H2O

txH2O Winter 2008

Changing Climates

By Kathy Wythe

Long before climate change and global warming became such a popular topic, scientists were researching the different aspects of the world's changing climate. In Texas alone, dozens of scientists from different universities and a wide range of academic areas are investigating the different components. More recently, they are taking information gleaned from the global climate models and applying them to research questions pertaining to Texas.

Dr. Bruce McCarl, Regents Professor of agricultural economics at Texas A&M University, has researched the economics of climate change for the last 20 years. McCarl, as a lead in the 2007 Nobel Peace Prize with the other scientists on the panel as well as Al Gore. His research has focused on economic effects of climate change on agriculture and forestry and their possible roles in mitigating climate change. He has published dozens of papers with colleagues and given presentations throughout the world on his research.

In a study published in 2001 on the Edwards Aquifer, McCarl and other researchers investigated the effects of climatic change on regional water demand and supply as well as the economy. Their results indicated that changes in climatic conditions would reduce water resource availability and increase water demand, McCarl said.

In his mitigation research, McCarl has proposed that agriculture can help reduce greenhouse gases. The first option, he said, is for agriculture to reduce and control direct emissions by reducing irrigation pumping, which uses energy; reducing fertilizer use, which produces the greenhouse gas, nitrous oxide; and improving manure management of livestock herds. The second way is by modifying agricultural management to enhance the stored carbon, thus increasing carbon sequestration. McCarl said agriculture could also generate products that offset fossil fuel-intensive products.

Another Texas A&M researcher, Dr. Gerald North, is an expert on simplified climate models, Earth observing satellites, ancient climates, and the detection and attribution of climate change. The Distinguished Professor of atmospheric sciences recently has been studying climate models to better understand how precipitation, evaporation, and runoff over the Greater Texas region will change over the next century.

In 2006, he chaired a committee for the National Research Council that reviewed the quality and reliability of temperature records from the last 2,000 years. North said the committee found that there was sufficient evidence to say with a high level of confidence that the last quarter century has emerged as the warmest in the last 400 years. It is plausible that the same holds for the last millennium, said North, who has also served in various capacities on past IPCC reports.

Research has also shown, North said, that the levels of greenhouse gases, carbon dioxide and methane, in the atmosphere were fairly constant over the last millennium until the Industrial Revolution. "Both greenhouse gases really started going up in the 1700s," North said, "and have been going up exponentially ever since."

North and his colleagues in Texas A&M's Department of Atmospheric Sciences issued a statement supporting the IPCC reports and findings. The statement is available at http://www.met.tamu.edu/climatechange.php.

Katharine Hayhoe, associate professor of geosciences at Texas Tech University, uses global and regional climate model simulations to determine what climate change means to the places where we live. As a current contributor to and expert reviewer of the latest IPCC report, Hayhoe also shared in the Nobel Peace Prize. She is currently collaborating with researchers from the University of Chicago, University of Illinois, and Harvard University on a National Science Foundation grant to develop new statistical methods to relate global climate projections to what will happen at the local scale.

She said people need specific examples about the effects of climate change, like an increase in the number of days a city might experience over 100 degrees Fahrenheit, or a change in the frequency of drought conditions. "People need this type of information to make decisions," she said, and individual cities need the information to make decisions when planning for the future.

"As individuals, we need to see how climate changes will affect where we live because we are being asked to make lifestyle changes to prevent potentially dangerous impacts of climate changes," she said. "If we don't know what those impacts are likely to be for us personally, it's hard to be motivated to make those changes."

Professor of atmospheric sciences at Texas A&M and the state's climatologist, Dr. John Nielsen- Gammon, researches climate variability and change in the past. He has also investigated regional drought causes and mechanisms, including specific meteorological factors that lead to lack of rainfall in the summer, hurricane frequency, and climate data quality.

In one project, he is working with the Institute for Science Technology and Public Policy of The Bush School of Government and Public Service, providing climate data for a project studying drought and drought variability over the past century in Texas and New Mexico and policy makers' perceptions of drought. His research is specifically "looking at spatial patterns of droughts in the past and frequency and whether precipitation and drought has changed significantly over the past 100 years," he said. He has found that total precipitation has increased in Texas by 10 to 20 percent over the past 100 years.

"We don't know whether this is something that is dynamically driven by changes in the sea surface temperatures, for example, or whether it is a consequence of anthropogenic activities such as increased irrigation or changes in the particles in air that control the formation of clouds and precipitation," he said. "Since we don't know why the trend is there, we don't know whether the trend will continue in the future or reverse itself."

This project is one of two that are focused on climate change at the Bush School institute, according to Dr. Arnold Vedlitz, director.

Both projects are examining how decision makers and other stakeholders use science information about global climate change in their decision making process. Vedlitz said the researchers have done regional studies on the Gulf Coast, national studies of decision makers, national public opinion polls and interviewed a national sample of climate scientists to determine how different stakeholder groups use climate change information.

The second part of their research is answering the question, "How can we make this information more usable to decision makers?" Vedlitz said. The researchers are developing decision tools and models to help decision makers make better use of the information.

Part of the research of Dr. Steven Quiring, Texas A&M assistant professor of geography, is focused on the influence of global climate change on the hydrologic cycle and drought. Using records from the past, Quiring said he can study drought and its natural variability to put it into proper perspective to help detect future changes from climate change.

"We need to use the observational record to make sure we understand how the system works," Quiring said. "Once we understand how the system works then that is the jumping off point for climate change."

He said that by looking at the observational record, scientists can see if the predictions from the global models have started to take place, thus validating those models projections.

In research funded by the U.S. Department of Energy through the Southeastern Region of the National Institute for Climatic Change Research, Texas A&M researchers Drs. Mark Tjoelker and David Briske of the Department of Ecosystem Science and Management and Astrid Volder of the Department of Horticultural Science are conducting a large, multiyear experiment near the Texas A&M campus. They are examining the effects of climate warming and drought predicted within the next several decades on the post oak savannas and woodlands of central Texas.

Through three years of controlling the temperature and rainfall to mimic predictions, Tjoelker said their research suggests that juniper will increase in dominance and invasiveness in savanna grasslands with both climate warming and increased summer drought.

Dr. Carrie A. Masiello, assistant professor of earth science at Rice University, studies the Earth's carbon cycle on timescales from five to 100,000 years. Her main interests are in fundamental mechanisms of the carbon cycle and how humans are altering these mechanisms through combustion of fossil fuel, land use change, and erosion. Masiello and her group, Rice Isotope Biogeochemistry, are currently studying how changes in climate and land use are controlling river carbon cycling.

At The University of Texas at Austin (UT), researchers at the Environmental Science Institute (ESI)-a multi-disciplinary institute for basic scientific research in environmental studies-are examining different aspects of climate change. Dr. Jay Banner, director, said its work includes climate change history, impacts, remediation and education, climate modeling, records, and abrupt climate change.

Dr. Zong-Liang Yang, associate professor in the Jackson School of Geosciences, and his Land Environmental and Atmospheric Dynamics (LEAD) group are studying the impacts of climate change on a finer scale. They are using various computer models to study the interaction of land use and the atmosphere.

Yang said current global climate models are too course for local and regional applications. His research group has developed dynamical downscaling to mitigate this problem.

For a National Aeronautics and Space Administration grant, Yang, along with other ESI-affiliated researchers, are using a series of nested computer models that integrate climatic, hydrologic, ecological, and atmospheric processes to study how climate change on the global scale will affect people locally. The team is using the computer model to study the Nueces and Guadalupe watersheds.

The real power of this model, though, said Yang in a Jackson School news release, is that, with some modifications for the local landscape and human population, it can be applied to many other places around the world, including developing countries that are struggling to sustain growing populations.

Other UT researchers involved in the project are Drs. Guo-Yue Niu, Jackson School; David Maidment, Department of Civil, Architectural and Environmental Engineering; James McClelland, Marine Science Institute; and Hongjie Xie, Department of Earth and Environmental Science, University of Texas at San Antonio. Dr. Paul Montagna of the Harte Research Institute at Texas A&M at Corpus Christi is also a member.

Dr. Charles Jackson, research scientist at the Jackson School's Institute for Geophysics, is an expert in global climate change of the past-particularly episodes of abrupt climate change within the past 100,000 years. Jackson also works on quantifying climate prediction uncertainties in order to understand how records of past change may be used to build confidence in model predictions of the future.

Dr. Bridget Scanlon, hydrogeologist at the Bureau of Economic Geology of the Jackson School, looks broadly at both regional and global water resources within the context of climate variability and land use/land cover change.

Through a National Science Foundation research grant, Dr. John Holbrook, professor of Earth and environmental sciences at The University of Texas at Arlington, is examining the rates and processes by which the Missouri River changes its pattern and erosion trends due to climate change.

"The research will help us understand how surface water supply from the Great Plains and Eastern Rockies changes in response to shifts in climate," Holbrook said.

Although the area being studied is the Missouri Drainage, he said researchers will gain insight into how the High Plains, including parts of Texas, responded in general to climate change over the past 5,000 years.

Dr. Arne Winguth, assistant professor of earth and environmental sciences at UT at Arlington, has started analyzing recent climate records of Texas, particularly the northern part of the state. Winguth plans to process the recent climatic trends in Texas and compare these data with predictions from the IPCC.

"This research is of importance for a better understanding of the future climate evolution in Texas," Winguth said.

Professor of geography at Texas State University, Dr. David Butler, does climate change research mainly in the Rocky Mountains with U.S. Geological Survey funding. He has also done research on how climate change is affecting floods in Central Texas and on the relationships of climate change with range expansions of fire ants and their interaction with native animals.

"Climate change in Central Texas will probably make flood forecasting more unpredictable than ever, as climatic extremes seem to become more common," Butler said.

Dr. Richard Dixon, associate professor of geography at Texas State, researches a vulnerability analysis of tropical systems for Texas coastal counties, the impact of inter-annual climate variability on temperature, and precipitation in Texas, vulnerability of south Texas to tornadoes, and reassessment of storm and flood probabilities for south-central Texas. His doctoral students are investigating regional climate change in the Big Bend National Park area, and spatial and temporal trends in precipitation and evaporation in Texas.

The researchers said that, although Texas scientists are conducting much research, more needs to done, especially at the local level.

"It's been my contention for 20 years that we haven't been doing enough research on this question (climate change) in Texas," said Dr. Gerald North of A&M's atmospheric Sciences department.

For a list of Texas climate change researchers or to add names, visit http://twri.tamu.edu/climatechangeresearchers.

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