The Impact of Global Warming on Texas

[ Regional/Texas ]

The Impact of Global Warming on Texas

Second edition

Edited by Jurgen Schmandt, Gerald R. North, and Judith Clarkson

A completely revised and updated edition of the baseline study of global warming's potential effects on Texas.

2011

$30.00$20.10

33% website discount price

This is a print-on-demand title. Expedited shipping is not available.

Paperback

6 x 9 | 328 pp. | 2 maps, 54 charts, 39 tables

ISBN: 978-0-292-74405-9

When The Impact of Global Warming on Texas was first published in 1995, it discussed climate change as a likely future phenomenon, predicted by scientific studies. This entirely rewritten second edition presents evidence that early climate change impacts can now be observed and identifies the threats climate change will pose to Texas through the year 2050. It also offers the hopeful message that corrective action, if taken now, can avert unmanageable consequences.

The book begins with a discussion of climate science and modeling and the information that can be derived from these sources for Texas. The authors follow this with an analysis of actual climate trends in the various Texas climate regions, including a predicted rise in temperatures of 5.4 degrees F (plus or minus 1.8 F) by the end of the century. This could lead to less rainfall and higher evaporation, especially in regions that are already dry. Other important effects include possible changes in El Niño (climate variability) patterns and hurricane behaviors. Taking into account projected population growth, subsequent chapters explore likely trends with respect to water availability, coastal impacts, and biodiversity.

The authors then look at the issues from a policy perspective, focusing on Texas's importance to the national economy as an energy producer, particularly of oil and gas. They recommend that Texas develop its own climate change policy to serve the goals of reducing greenhouse gas emissions, increasing energy independence, ensuring regional security, and improving management of water, air, land, and wildlife.

  • Foreword (Neal Lane)
  • Introduction (Bill Dawson)
  • Chapter 1. Climate Science and Climate Change (Gerald R. North)
  • Chapter 2. The Changing Climate of Texas (John W. Nielsen-Gammon)
  • Chapter 3. Water Resources and Water Supply (George H. Ward)
  • Chapter 4. Coastal Impacts (Paul A. Montagna, Jorge Brenner, James Gibeaut, and Sally Morehead)
  • Chapter 5. Biodiversity (Jane M. Packard, Wendy Gordon, and Judith Clarkson)
  • Chapter 6. Agriculture (Bruce A. McCarl)
  • Chapter 7. Urban Areas (David Hitchcock)
  • Chapter 8. Greenhouse Gas Emissions (Judith Clarkson)
  • Chapter 9. Economy (Jared Hazleton)
  • Chapter 10. Policy (Jurgen Schmandt)
  • Contributors
  • Index

This book is being published at a moment of singular change and choice for Texans. As the authors make clear, the impact of global warming on the state is expected to take two basic and interrelated forms. One involves the effects of warming-caused climate change itself. The second involves the effects of any actions taken to reduce that warming.

First, geography means Texas will experience a challenging assortment of the climate changes that scientists have concluded are already spinning off from a man-made atmospheric warming trend. Chapter 10, for instance, includes a compelling, though hardly comprehensive, list of some of the things that scientists project for the state: "temperatures will rise, heat waves will occur more frequently, it will be drier west of the Interstate 35 corridor, severe weather will become more frequent, in-stream flows will fall, biodiversity will decline, and the sea level will rise."

Meanwhile, because of its energy-intensive economy and way of life, Texas will acutely feel the effects of any new policies designed to reduce emissions of carbon dioxide (CO2), the principal greenhouse gas blamed for man-made warming. Carbon dioxide is emitted whenever fossil fuels, including oil and coal, are used. In Texas, the sources include millions of motor vehicles, sprawling oil and chemical complexes that serve much of the nation, and the coal-fired power plants that produce much of the state's electricity. Chapter 8 examines the factors behind Texas' high ranking among states emitting the most carbon dioxide. Two telling details: Texas leads the United States in overall energy use, with more than a tenth of the national total, and also in the consumption of coal.

This new, second edition of The Impact of Global Warming on Texas can aid in making the decisions that now confront the state. It is a completely revised version of the original edition, published in 1995. The authors—a distinguished team of climate scholars representing a variety of disciplines—present up-to-date interpretations of experts' current knowledge of the scientific, economic, and policy aspects of climate change in the state.

The book also offers recommendations for two major realms of possible response to global warming, reducing its impacts and adapting to those effects. The authors' work will nourish the understanding of policymakers and ordinary citizens alike at a particularly significant time in the climate issue's trajectory. In Chapter 10, Jurgen Schmandt notes that leaders now have "fewer excuses to defer action because of scientific uncertainty" than they did when the book's first edition was published, because researchers have resolved key questions in the ensuing 15 years. In addition, he writes, scientists have established that "climate change is no longer a distant possibility but is occurring now."

The likelihood that more-ambitious national policies will be adopted to reduce carbon dioxide emissions, including regulatory mandates, has increased as accumulating scientific findings and solidifying interpretations of that research have influenced and intersected with a number of other events and trends.

President Barack Obama promised change in his 2008 campaign for the White House, including a reversal of Texan George W. Bush's refusal to launch a regulatory attack on human-caused climate change. Within just a few days of taking office, Obama signaled that he would make good on that pledge when his administration proposed major increases fuel economy for cars and light trucks. The regulations, adopted in April 2010, include the nation's first-ever standards for greenhouse gas emissions.

Still to come, at this writing, is final action that would fulfill Obama's campaign pledge to enact a sweeping regulatory program aimed at reducing emissions of greenhouse gases from sources other than vehicles. Major steps have been taken toward that goal, both administratively and in Congress, but the issue is highly contentious and the outcome remains unclear. A major bill to limit greenhouse emissions narrowly passed the House in 2009, but the Senate has not approved that measure or its own climate legislation. On a separate track, the U.S. Environmental Protection Agency (EPA) in December 2009 finalized action on its formal conclusion that greenhouse gases endanger human health and the environment. This "endangerment" finding is a legal prerequisite before the EPA regulates such gases on its own initiative under the federal Clean Air Act. The finding is being challenged in court by a number of private interests and states, including Texas.

Obama's election, significant as it was for the climate issue, was just one in a series of major developments that have transformed the character of climate change as a political and economic issue in the last few years. Hurricanes Katrina and Rita, which devastated parts of Louisiana and Texas in 2005, profoundly heightened awareness and concern about the effects of global warming, including stronger storms, that climate scientists project. In 2006, a documentary film and book by former vice president Al Gore, both titled An Inconvenient Truth, used hurricane images among other visual and verbal tools to persuade the public to take climate change more seriously. Media coverage of a stream of scientific findings, including the 2007 reports of the Intergovernmental Panel on Climate Change (IPCC), likewise accelerated attention to the issue.

The IPCC, reflecting the work of hundreds of scientists around the world, declared that evidence of warming was "unequivocal" and that most of the warming that has occurred over the previous half-century was "very likely" the result of greenhouse emissions from human activities. The organization's reports contained warnings about possible consequences of deep concern for Texas, including hurricanes ("likely" to grow stronger, according to the IPCC), rising sea level (which boosts hurricane storm surges), and climate events including heat waves, high temperature extremes, and heavy precipitation ("very likely" to be more frequent). Early in 2007, An Inconvenient Truth won an Academy Award. Later in the year, Gore and the scientists who worked on the IPCC reports were jointly awarded the Nobel Peace prize for heightening awareness of the issue.

In 2008, just four months before this edition's preview appearance in an online format, Hurricane Ike roared ashore in Texas, bringing destruction to Galveston and the Bolivar Peninsula, knocking out electric power to millions of Houston-area residents and exacting an enormous economic toll that made the storm one of the costliest in American history. In the 2008 presidential campaign, both Obama and his Republican rival, Senator John McCain of Arizona, endorsed regulatory proposals for battling climate change that had far more in common with one another than either did with the nonregulatory approach followed for eight years by Bush. By the end of Bush's second term, the national discussion about climate change, dominated by a clamorous debate over science until not that long ago, had become more focused on policy questions about what to do about this phenomenon that was being identified by a growing body of research.

Along with changed perceptions and a shifting public dialogue, climate change has increasingly blended with related concerns in the political arena, news coverage, corporate decision making, and elsewhere. The result is a larger, composite issue that encompasses global warming, energy policy, pollutants other than carbon dioxide that come from the same sources, dependence on foreign oil sources, national security, and the broad concept of sustainability. Terms like "going green" and "carbon footprint" quickly became widely familiar through repeated usage in the popular media, both news and entertainment. The New York Times, for instance, introduced "Green Inc.," a multi-reporter blog that focuses on the intersection of business, the economy, and the environment. The newspaper described the blog's mission this way: "How will the pressures of climate change, limited fossil fuel resources and the mainstreaming of 'green' consciousness reshape society? Follow the money."

When the economic meltdown that took place during the latter part of 2008 morphed into a deepening recession, it focused new attention on concepts like "green stimulus" and "green New Deal." They refer to government programs designed to revive the economy through spending to boost alternative energy, energy conservation, energy efficiency, and the like. Obama endorsed such ideas in his campaign, and his economic stimulus proposal included funding for such initiatives.

All these changes, then, have contributed to a growing array of choices for Texans about how they will respond to the interconnected issues of climate, energy, and economy. At the state government level, for instance, Bush's decision not to pursue regulations to limit global warming created a policy void that has increasingly been filled by the actions of individual states and multistate compacts to tackle the climate issue directly. Texas has not been one of them. "So far, Texas has done very little to address the problem of global warming," Judith Clarkson writes in Chapter 8. "In fact," she adds, "the official policy appears to be to wait and see what the federal government does."

With the Obama administration adopting an approach to climate change very different from that followed by Bush, a key question looms larger than ever: Will government leaders in Texas still wait to see what federal policy means for the state (while trying to influence that policy, to the extent they can), or will they also begin to shape a complementary Texas response to global warming?

Early in 2009, as the new national administration was just starting to implement its own policies, it seemed that state lawmakers might begin forging a new path for Texas. The new speaker of the House of Representatives, Republican Joe Straus of San Antonio, was an outspoken proponent of energy efficiency and had told Texas Monthly magazine that he looked forward to the day "when alternative energy is a mainstream source to power Texans' lives." Other indications also gave advocates strong hope that the 2009 legislative session would produce various bills that would have the effect of cutting greenhouse emissions.

That optimism was largely unfulfilled, however, as major bills on renewable energy, energy efficiency, and related matters that had seemed likely to pass instead died in the session's last hours in a legislative logjam. Still, other bills were passed that for the first time in Texas explicitly recognized climate change attributed to greenhouse emissions with requirements for state officials to carry out certain planning and information-collecting activities.

One of these successful measures, called "No Regrets," could lead to future legislative action. The proposal, by an Austin Democrat, State Senator Kirk Watson, had failed to pass in the 2007 session. As enacted in 2009, it required state officials to solicit and analyze strategies for cutting greenhouse emissions that would result in net savings for consumers or businesses, bring no financial costs, or help Texas businesses "maintain global competitiveness." The State Energy Conservation Office was to submit a report on the strategies to the Legislature in time for possible consideration in the 2011 session.

In Chapter 10, Schmandt argues that Texas has been pursuing what is essentially "a hidden climate change policy," motivated largely by concerns about energy independence and efficiency. The hidden policy, he asserts, includes various efforts to advance alternative energy and energy efficiency and is more ambitious than many people recognized. Schmandt calls instead for "a comprehensive policy that links climate change to energy independence, regional security, and the management of natural resources," along with the establishment of a state Office of Energy, Security, and Climate to focus such a unified, overt commitment.

Of course, taking such actions would require an acknowledgment that man-made climate change is an issue worth major and explicitly directed attention and resources. There have been suggestions that some high-ranking state officials do not share that viewpoint. For example, an advisory panel appointed by Governor Rick Perry and made up of top officials of three state agencies, argued in late 2008 against federal regulation of greenhouse emissions by the EPA. The panel's report signaled doubt about the interpretations of mainstream climate science in a brief passage asserting that "recent climate research calls into question prevailing public perceptions of the cause and extent of global warming."

High-level skepticism about the conclusions of mainstream climate science was expressed more explicitly and forcefully in February 2010, when Texas Attorney General Greg Abbott filed the state's petition challenging the EPA's endangerment finding about greenhouse gases. At that time, Abbott and Perry leveled harsh criticism at the IPCC and its conclusions. They based their arguments on news reports about a few errors in the IPCC's voluminous 2007 reports and about previously private e-mails of some climate scientists, which had been leaked or stolen from a British university and which climate change skeptics alleged were indications of data manipulation. Abbott said the IPCC was "not trustworthy," and Perry's office said it was "discredited."

Leading climate scientists at Texas universities soon disputed those arguments. Kenneth P. Bowman, who heads Texas A&M University's Department of Atmospheric Sciences, issued a statement saying the department's entire faculty believed the EPA finding was based on "good science." A few weeks later, scientists from Rice University, Texas A&M (including Gerald North, one of this book's editors), Texas Tech University, and the University of Texas at Austin coauthored an op-ed column in the Houston Chronicle, declaring that "the science of climate change is strong." (Before the state's petition was filed, the Associated Press conducted an "exhaustive investigation" of the disclosed e-mails, concluding that they "don't support claims that the science of global warming was faked." Subsequently, the British House of Commons Science and Technology Committee reached a similar conclusion.)

Perry has consistently argued that federal regulation of greenhouse gases would cripple the Texas economy. A better approach, he has said, is to make alternative energy technologies, such as wind-generated energy, less expensive, along with fostering investment in nuclear power and in technologies for capturing and sequestering carbon emissions.

The growth of Texas' wind-power industry is an instructive case study in the complexity and ambiguity of the stances and actions taken by state officials regarding human-caused global warming. Perry, for one, has delivered what some might regard as mixed messages. For instance, the same press release from the governor's office that called the IPCC "discredited" also suggested that cutting greenhouse gases is a worthy goal. It noted that Texas has "reduced carbon dioxide emissions more than nearly every other state," has done so without "government mandates or extravagant fines," and has "installed more wind power than any other state." Similarly, when Perry announced a $10 billion private-public partnership to expand wind-energy infrastructure in Texas in 2008, his office declared that "for every 1,000 megawatts generated by new wind sources, Texas will reduce carbon dioxide emissions by six million tons over the next 20 years."

On some occasions, Perry has made light of concerns about human alteration of the climate with greenhouse emissions. In 2007, news reports said he remarked to an audience in California (site of the most dramatic state-level actions to limit greenhouse gases), "I've heard Al Gore talk about man-made global warming so much that I'm starting to think that his mouth is the leading source of all that supposedly deadly carbon dioxide." In June 2009, voicing concern that the EPA might declare carbon dioxide (and other greenhouse gases) an air pollutant deserving regulation, he told reporters in Austin, "I mean the idea that CO2 is a toxic substance is a bit hard for this, you know, agricultural scientist to get his arms around when Nobel Peace Prize or Nobel laureates have talked about CO2 in a very positive sense, when you talk about the Green Revolution," which boosted agricultural production in developing nations.

Such pronouncements raise an obvious question: Why announce that the state's reductions in carbon dioxide are a benefit of the wind industry's growth in Texas—or why mention those reductions at all in a positive way—if the gas is only a "supposedly" harmful substance and the leading scientific body saying that it is harmful is "discredited"?

In any event, Texas now produces more electricity from wind generation than any other state, thanks in large part to actions by the Legislature in 1999, and again in 2005, requiring utilities to produce a certain percentage of electricity from renewable sources. In 2008, the Public Utility Commission launched a $5 billion project to increase transmission capacity, then in early 2009 pushed it ahead by giving seven utilities assignments to construct the new electric lines to carry wind energy from West Texas to North Texas and the Houston area.

Also in 2008, the prominent Texas businessman T. Boone Pickens gained considerable national attention through the heavy promotion of his Pickens Plan, a proposal to help wean the United States from its dependence on foreign oil through the use of wind and solar power and natural gas. Initially, Pickens suggested substituting natural gas for imported oil in some vehicles, including private cars, while replacing electricity now generated by that natural gas with more wind power. By early 2010, he had modified his plan to de-emphasize wind power and personal vehicles and emphasize converting large, diesel-burning 18-wheelers to use natural gas. Pickens stresses the benefits for national security of reducing reliance on foreign oil, rather than the lowered greenhouse emissions that would result from replacing oil with carbon-free wind and lower-CO2 natural gas. He told an audience at Rice University early in 2009 that "global warming is Page 2 for me." Nevertheless, he has made common cause with campaigners for attacking climate change, such as Al Gore and the Sierra Club.

Such alliances might seem odd (Gore is a liberal Democrat and Pickens is a conservative Republican), but they typify the synergistic opportunities that have arisen in recent years, along with the blending of the climate issue with other concerns. Texas is rich in natural gas reserves, and the fuel was being mentioned by some Texas officials as far back as the late 1980s as a weapon against global warming.

The promotion of natural gas and wind power in the Pickens Plan is only one recent sign of a growing recognition among private-sector leaders in Texas of a changing political and economic landscape with regard to the climate issue. For example, several years ago, before retiring as president of Shell Oil, John Hofmeister began calling for a "culture of conservation," including national policies that recognize global warming as a problem requiring action. In 2008, commenting on the possible EPA regulation of greenhouse gases that Perry opposed, officials of San Antonio-based AT&T said they were ready to help the federal agency cut emissions through the development of next-generation information and communication technologies.

Probably no corporation has been more closely watched or more strongly criticized on the climate issue than the Texas-based giant Exxon Mobil. During the George W. Bush administration, Exxon came under increasing attack for its influential opposition to the regulation of greenhouse gases. In 2006, the Royal Society, Britain's national sciences academy, called on the company to stop supporting groups that had "misrepresented the science of climate change by outright denial of the evidence" and for Exxon itself to cease issuing "inaccurate and misleading" statements on climate science. Exxon still has its critics over the climate issue, to be sure, but there is no denying that its public pronouncements have shifted dramatically. In 1991, the New York Times reported that Exxon's chairman, making a speech in Houston, had "expressed doubt that theories on global warming would eventually prove accurate."

In late 2008, an article in the Times included this passage:

Gingerly, over the last three years, Exxon has moved away from its extreme position (on global warming). It stopped financing climate skeptics this year, and has sought to soften its image with a $100 million advertising campaign featuring real company executives, scientists and managers. One of the ads said the company aimed to provide energy "with dramatically lower CO2 emissions."

Then, early in 2009, the Wall Street Journal reported this development: "The chief executive of Exxon Mobil Corp. for the first time called on Congress to enact a tax on greenhouse-gas emissions in order to fight global warming."

Climate-conscious transitions are evident in Texas beyond the arena of corporate policy. Sustainability initiatives have gotten under way at a number of colleges and universities, as administrators and students embrace policies and goals related to energy conservation, carbon reduction, and related matters. At the University of Texas, for example, a sustainability plan prompted by a student proposal was announced in 2008. The university said it would "integrate sustainability in academic programs, operations, campus planning, administration and outreach" in one of the most rigorous initiatives in the state. In early 2010, students at both the University of Texas and Texas A&M voted to levy small fees on themselves to fund campus sustainability projects. Meanwhile, curriculum offerings at various institutions of higher education reflect the same trend in different ways. In one example (of many that could be cited), Midland and Odessa colleges in West Texas recently announced that they would offer instruction in wind-energy technology.

City government is another arena where programs and policies that implicitly or directly address climate change have multiplied in Texas, reflecting a municipal trend that has paralleled state government initiatives across the country. Houston, Dallas, and other cities, for instance, formed the Texas Clean Air Cities Coalition, which joined forces with environmentalists and others in 2006 to oppose a proposal by the Dallas-based utility company then called TXU to build 11 new coal-fired power plants in Texas. The opposition was based on concerns about the health effects of smog-forming pollutants, as well as the carbon dioxide that the power plants would release over decades of operation. In 2007, the company was acquired by buyers who, after consulting with opponents of the plants, dropped plans for all but three of them. In 2008, the coalition, by that point numbering 37 cities representing more than half the population of Texas, and the Environmental Defense Fund dropped their joint opposition to the expansion of an NRG power plant after the company agreed to implement measures that would offset a large part of the coal-fired plant's carbon dioxide emissions.

By early 2010, 31 Texas mayors had committed their cities to the goals of the U.S. Mayors Climate Protection Agreement, a pact managed by the U.S. Conference of Mayors and signed by more than 900 mayors. Texas participants range from large cities (including Austin, Dallas, Fort Worth, and San Antonio) to smaller ones like College Station and Sugar Land. The agreement commits participants to try to meet or exceed the carbon dioxide reduction targets in the Kyoto Protocol, an international climate treaty, and to urge their states to do the same. The agreement is discussed in Chapter 8, which also provides a detailed account of climate-related initiatives in Austin. The capital city, Judith Clarkson reports, takes pride in being a municipal leader in reducing fossil fuel consumption.

Participation in the U.S. Mayors pact does not convey the full extent of the efforts by Texas cities to cut greenhouse emissions and otherwise deal with climate change. Houston, the state's largest city, has not signed the agreement but has launched a number of climate-linked projects in recent years. They include a project undertaken in concert with the Clinton Climate Initiative (named for the former president) to improve energy efficiency in municipal buildings through retrofits.

Besides such actions aimed at reducing carbon emissions, Houston has taken steps to be better prepared for hurricanes following its experience with Hurricane Ike in September 2008. Two months later, responding to the massive power outages that Ike caused, Houston's mayor, Bill White, appointed the Task Force on Electric Reliability, made up of individuals with relevant expertise, to recommend how to make the power grid "more durable and resilient."

Heightened preparedness for strong hurricanes like Ike also has been on the minds of Houston-area citizens, as reader comments on the Houston Press website in early 2009 illustrated. Regarding an article relating Galveston's struggles to recover from the storm, a Galveston resident wrote, "The No. 1 issue is now to minimize or eliminate catastrophes in the future, whether it involves raising houses or providing surge protection on the bay." A Houstonian added this comment, referring to the famous seawall that Galveston residents constructed after their city was devastated by the catastrophic hurricane of 1900: "Galveston has a dike, but it stops after ten miles. Did Ike know it was not supposed to go beyond the dike and flood the city from the back side? I grew up in Holland, where taxpayers spend billions of dollars on keeping their feet dry. What do we do here? Pray!"

Since then, government officials and others have begun considering the construction of a massive Ike Dike, a Netherlands-inspired system of levees, seawalls, and floodgates to extend the storm-surge protection of Galveston's seawall in both directions along the coast. As envisioned by William J. Merrell, the George P. Mitchell Professor of Marine Science at Texas A&M University at Galveston, a wall 17 feet high would extend 60 miles, from High Island west to San Luis Pass. At this writing, the county judges of six counties in the Houston-Galveston region are planning a formal study of the concept.

Preparedness for stronger hurricanes and other possible outcomes of climate change is a key theme that runs through the diverse contributions assembled in The Impact of Global Warming on Texas. Neal Lane, in the Foreword, urges that global warming be treated as "a risk management problem." Time will tell whether Texans and their leaders adopt that viewpoint. If they do, the careful, comprehensive, and evidence-based assessments in this book can serve as a useful guide. In any event, the book's publication means the state is being briefed at a crucial time about the risks and opportunities that some of Texas' most knowledgeable climate experts foresee.

The Authors' Summary of Their Key Conclusions

Climate Science and Climate Change: Climate science has evolved over the last 35 years to a point where predictions by climate models can be considered to have significant information content. The greenhouse effect has been clearly established as a driver of climate change, and the main agent is the continuing increase in the concentration of carbon dioxide in the atmosphere. There are several ways of assessing the status of climate change research. The most recent and comprehensive assessment is from the Intergovernmental Panel on Climate Change, the Fourth Assessment Report, released in 2007. According to this report, greenhouse gases are expected to cause global temperatures to rise 5.4°F (plus or minus 1.8°F) by the end of the century. Temperature changes in Texas are expected to be comparable. A notable feature of the predictions is the expansion of the tropical zone, familiar in summer for Texans, to include more of the spring and fall. This could lead to less rainfall, especially in regions that are already dry. Other important effects include possible changes in El Niño (climate variability) and hurricane behavior; further research will more accurately specify these and other effects.

The Changing Climate of Texas: Texas precipitation increases dramatically from west to east. The seasonal patterns of precipitation also vary greatly across the state (e.g., dry winters in the west, more even distribution seasonally in the east). Texas experiences a variety of severe weather, such as tropical storms, tornadoes, drought, and flooding. The wide variations in weather and climate across Texas imply a broad range of vulnerabilities to climate change. Averaged across Texas, the temperature has been increasing over the last few decades. Precipitation has also steadily increased over the past century, but with variation among regions. In the future, Texas temperatures are likely to continue rising. Precipitation changes are much less clear, with most models projecting a decrease. Even if precipitation were to remain stable, rising temperatures would increase evaporation and dryness. The expected changes in temperature and precipitation will have an impact on other sectors of the state's resources.

Water Resources and Water Supply: Taking water flows to the coast as a measure of river basin impact, we calculate which changes will occur by mid-century under constant and changing climate conditions. Considering only population growth and the resulting increased water demand, flows will be reduced by about 25 percent under normal conditions and by 42 percent under drought conditions. When also considering climate change (3.6°F increase in air temperature and 5 percent decrease in precipitation), 2050 projected flows to the coast are 70 percent of the 2000 values under normal conditions and 15 percent under drought conditions.

Coastal Impacts: Two direct effects are already observable in the instrumental record: rapid sea-level rise and rising sea temperature. The rates of sea-level rise are especially high in Texas because of the added effect of land subsidence, which is caused by oil and groundwater extraction. The increasing temperatures are already manifesting indirect changes in habitats and water quality.

Biodiversity: Climate is a key determinant of species distribution. As the earth warms, species tend to shift to northern latitudes and higher altitudes. But climate change represents just one of a set of stressors. Other changes challenging fauna and flora are due to land development, habitat fragmentation, invasive species, chemical stressors, and direct exploitation. Comprehensive assessments in each of the state's ecological regions (coastal marshes, forests, deserts, prairies, and western mountains) are needed to develop science-based management practices for wildlife and plant communities.

Agriculture: Agriculture in the United States and Texas is sensitive in terms of land and water uses, as well as crop and livestock production. In terms of agricultural-based economic welfare, however, the simulated effects of climate change are not large. We find that under the climate change conditions simulated herein, statewide Texas cropped acreage declines by about 20 percent.

Urban Areas: Coastal population centers, from Houston to the Lower Rio Grande Valley, are vulnerable to rising sea level, increased storm intensity, and the accompanying flooding. All major Texas cities face the possibility of impacts on air quality, energy, health, and other temperature-related effects. All major cities face the prospect of declining water resources within the time frame examined here.

Greenhouse Gas Emissions: Because of its large population and energy-intensive economy, Texas leads the nation in oil refining capacity and energy consumption, accounting for more than one tenth of total U.S. energy use and 11 percent of U.S. greenhouse gas emissions. Although more than 30 states have taken some measures to address the issue of global climate change, Texas has not been willing to take direct action. It has, however, been a leader in renewable energy, and following legislative action in 1999 and 2005, Texas leads the nation in wind power production. There are many other, cost-effective measures that could be taken that would both reduce greenhouse gas emissions and improve the competitiveness of Texas products.

Economy: Looking to mid-century, it is clear that the cost to Texas of a national cap-and-trade policy would likely exceed any possible measurable benefit in terms of avoided damages. Over a longer time frame, if the harmful impacts of climate damage continue to increase, the cost-benefit balance might shift, but time is not on our side. Texas would benefit economically by taking stronger actions today to address climate change impacts at the state level and by supporting the adoption of cost-effective, equitable policies at the national level to limit greenhouse gas emissions and encourage the use of alternatives to fossil fuels.

Policy: Texas is a leader in the gradual shift to renewable energy. Energy and water conservation are also priorities, mostly at the community level. The driving forces of these policy initiatives are energy efficiency, resource conservation, and the income and jobs associated with industries developing alternative energy sources. These measures help to reduce greenhouse gas emissions. Thirty states have joined regional climate change alliances. Texas has not done so. We recommend that Texas develop a comprehensive climate change policy to serve the goals of reducing greenhouse gas emissions, increasing energy independence, ensuring regional security, and improving management of water, air, land, and wildlife.

Jurgen Schmandt is Professor Emeritus, Lyndon Baines Johnson School of Public Affairs, the University of Texas at Austin and Distinguished Fellow, Houston Advanced Research Center.

Gerald R. North holds the Harold Haynes Endowed Chair in Geosciences in the Department of Atmospheric Sciences at Texas A&M University.

Judith Clarkson works in environmental consulting, particularly on water-related projects, and writes and edits materials related to acid rain and climate change.