Introduction
Introduction Doing Science Science & Society Our Environmental Heritage The Science of Global Change Summary
The materials of science are the material of life itself. Science is part of the reality of living; it is the what, the how, and the why of everything in our experience. It is impossible to understand man without understanding his environment and the forces that have molded him physically and mentally. The aim of science is to discover and illuminate truth. Rachel Carson
Whatever knowledge is attainable, must be obtained by scientific methods, and what science cannot discover, mankind cannot know. Bertrand Russell Introduction
• Earth science, geology and environmental geology involve the study of the Earth and the processes that shape its surface but have different emphases. • The Earth System is composed of four principal components: atmosphere, hydrosphere, biosphere, and the solid Earth. • The science of Earth becomes relevant to society when we examine the interaction between human beings and the planet we share.
The Good Earth represents an attempt to introduce students to Earth Science with an emphasis on our interaction with our environment. Consequently, this text includes components from two common undergraduate courses, Earth Science and Environmental Geology. These courses have more elements in common than they have differences. • Geology is the study of the Earth. That includes how the planet was formed, what it is made from, and how it has changed over time. Geologists study the processes that occur on Earth's surface and others taking place within the planet's interior. • Environmental geology views geology through the prism of the human experience. Environmental geology traditionally places less emphasis on the origin and history of the planet and focuses on geologic hazards, the consequences of resource development, and the alteration of the natural environment. • Earth science is broadly defined as the study of the interactions of the four components of the Earth system - the atmosphere, hydrosphere, biosphere and solid Earth. Consequently, it overlaps with other disciplines such as meteorology (weather systems, climate), oceanography (ocean processes), biology (ecosystems), and geology.
However, increasingly, the boundaries between Earth science and environmental geology are blurring as scientists define environmental problems at a global scale that require us to understand the interaction between all elements of the Earth system. Consequently, this text looks at the interaction between society and the Earth system as a whole. For the study of Earth to be relevant to our lives it must involve an examination of how people are affected by the processes that shape the Earth
2 and how we utilize the planet's resources (minerals, energy, water, air, soil).
The Good Earth describes the interaction of rock on and below the surface of the solid Earth with waters of Earth's hydrosphere (streams, lakes, oceans), and the processes of Earth's atmosphere that give us our daily weather and long- term climates. These components fit together to form the earth system, an environment that supports life on and near Earth's surface (biosphere). None of these components can exist without the others. Without the oceans there would be little source of water to evaporate to supply the atmosphere with precipitation. Without the atmosphere bringing precipitation, rocks could not break down to form soil. Without soils Figure 1. The principal vegetation would not flourish to absorb the toxic carbon components of the Earth dioxide that we exhale and produce the oxygen we inhale (see system include the solid Fig. 1). Earth (rocks, internal and surficial earth processes), This chapter is divided into six principal sections, including the hydrosphere (streams, this introduction. We begin with the basics, describing the oceans, ice caps), the scientific process itself. In the section titled Doing Science we atmosphere (weather, explain how scientists conduct investigations that allow them climate), and the to weave together data collected from experiments and biosphere (population, observations of the natural world. The application of the ecosystems, land use). Image courtesy of NASA's scientific approach is illustrated by discussions about the planetary photojournal. extinction of the dinosaurs and the investigation of a hypothesis of a potentially dangerous earthquake source in the Great Plains. We also examine cases where individuals attempted to circumvent the rigors of the scientific process to forward controversial ideas founded on poor science.
Mankind has been unconsciously interacting with the environment since our human ancestors began to roam the earth. Our demands on the planet have been magnified as technology evolved and population increased. The principal elements of the environment (air, water, soil) have specific chemical and physical characteristics that can be readily measured. Scientists can determine the volume of dust in the air or the abundance of a chemical in a stream to determine if the air or water quality falls below community standards. The presence of specific pollutants in the environment can be readily detected and steps can be taken to protect the health of the community and of natural ecosystems. For example, the Toxic Release Inventory (TRI) required companies to notify their communities about the volume of toxic emissions. Following the release of the first figures in the late 1980s,
3 emissions declined precipitously as many companies learned it was both good business and good public relations to reduce emissions.
Such social or cultural influences on decisions affecting the environment are more difficult to quantify than physical and chemical conditions. Consequently, they are more complex to Regulations that evaluate in decision making and are often the subject of measure physical or vigorous debate. Furthermore, the influence of these factors chemical environmental change with time as social perceptions change. For example, characteristics our view of the role of wilderness has evolved in the four Clean Air Act hundred years since the earliest European settlers arrived on Safe Drinking Water Act the North American continent. Wilderness was regarded with hostility by early colonists who considered the virgin forests to Examples of legislation be home to hostile natives and mythical beasts. However, as enacted for cultural population expanded and the number of wilderness areas concerns dwindled the remaining natural lands began to be considered Wilderness Act Endangered Species Act important cultural asset and were protected by legislation such as as the Wilderness Act (1964).
The third section of the chapter, Science and Society, examines how our knowledge of the Earth allows us to protect people from hazardous earth processes, manage economic resources, and protect the Earth from activities that may endanger natural ecosystems. We discuss the principal roles of the Earth sciences in our lives, from the benefits of basic research to the implications of global change for the future of humanity. This section serves as an introduction to these themes that are present throughout The Good Earth. Links to specific chapters are included, think of the Science and Society section as a road map of the text.
Americans’ interaction with the environment can be traced back to the continent's earliest inhabitants. However, it was the actions of European colonists that first resulted in widespread environmental degradation and led to early legislation to protect wildlife. An appreciation for the land blossomed in the nineteenth century, prompting the creation of forest reserves and the earliest national parks. This century has been marked by a growing concern for pollution of the environment at both regional and global scales. Two sections of the chapter divide our collective environmental heritage into two parts (Environment pre-1899, Environment post-1900) and examine the evolution of environmental thought in the U.S.
4 Finally, we finish the chapter by introducing the concept of global change, an idea that is currently generating research in a variety of disciplines including geology, ecology, chemistry, oceanography, and climatology. In this chapter we will describe the scale of the scientific enterprise behind investigating a substantial problem such as global change. It will become evident that such research requires the work of thousands of scientists throughout the globe. This research has implications for the long-term quality of life for humanity and is likely to require difficult social decisions within your lifetime. Future economic, cultural, and political choices in all the world's nations will depend on the rate and degree of global change. We will follow the theme of global change through many of the chapters of The Good Earth. Global change represents a consistent idea that we will use to link together the principal components of the Earth system to illustrate how tightly the atmosphere, hydrosphere, biosphere and solid Earth are linked together.
Think about it . . . 1. Examine the photograph located below and identify the components of the Earth system represented in the image, and consider what information we would need to have about the natural environment to live in such a location.
2. Draw a concept map that illustrates examples of interactions between the four components of the Earth system.
5
Doing Science
• Scientists use observations to form testable hypotheses. • Inaccurate hypotheses often do not follow the traditional procedure for formulating scientific ideas.
Science advances by the application of the scientific method, a systematic approach to answering questions about the Earth. We make the assumption that the components of the universe interact in a consistent manner. The scientific method infers that sufficient observation can reveal patterns that can be The construction of interpreted to understand the origin and history of Earth and to hypotheses is a predict future events in the Earth system. Earth science is a creative act of detective story, where circumstantial evidence is pieced inspiration, intuition, together by teams of scientists to generate imaginative invention; its essence explanations of the workings of our home planet. These is the vision of explanations are constantly being refined and/or challenged something new in causing some to be discarded while others gain wide familiar material. M. Friedman acceptance.
Most institutions From Observation to Theory demand unqualified faith; but the institution All of us make observations that we use to mold our personal of science makes views of the cultural and physical worlds we inhabit. Through skepticism a virtue. experience we test the limits of our personal world, allowing R.K. Merton them to expand to accommodate a positive stimulus or recoil from a negative interaction. Scientists also use observations to mold ideas. Their ideas are known as hypotheses. Personal observations will vary with the individual but valid scientific observations are empirical, that is, they can be measured and confirmed by others.
A scientific hypothesis (usually several competing hypotheses) is developed to provide a potential explanation of the observations. Hypotheses can be generated and tested using two basic reasoning procedures; inductive and deductive reasoning (Fig. 2). Inductive reasoning results when scientists draw general conclusions from specific observations. The success of this method comes from recognizing patterns and identifying similarities between comparable systems. In contrast, deductive reasoning occurs when scientists draw specific conclusions based upon general principles. Deduction may be based upon the application of laws or rules (e.g. law of
6 gravity). This type of reasoning is useful when we cannot readily identify the cause of a natural event.
Figure 2. An idealized flowchart for two types of scientific reasoning. Deductive reasoning occurs when scientists draw specific conclusions based upon general principles. Inductive reasoning results when scientists draw general conclusions from specific observations. Inductive reasoning is Consider the statement, red sky at night is a sailor's delight, red based on experience. sky in the morning is a sailor's warning. If we were to view a red sky we could apply deductive reasoning to form the hypothesis that it would be followed by good or bad weather. However, the original statement was generated as a result of inductive reasoning based upon numerous observations of the relationship between sky color and subsequent weather conditions.
The best hypotheses are logical and can be readily tested by experiment or by further observation. Continued observations over time will confirm if a hypothesis is accurate or if it needs to be further refined. New information may become available with the development of increasingly sophisticated technology and lead to minor or major changes in existing hypotheses. When a hypothesis has undergone sufficient inspection and has been found to yield consistent results it is promoted to a theory. (Later in this text we will discuss the theory of plate tectonics). With time, theories about some of the most basic characteristics of science may be termed scientific laws.
Few hypotheses or theories remain unchanged and none can ever be proved. Widely accepted ideas will be confirmed and strengthened by the work of many scientists but it is always possible that the next person to test the idea may discover a different result and falsify the hypothesis. This is the strength of science, the willingness to continually question prevailing ideas and to modify or discard them as new information becomes available. There are no sacred cows in science, it is an open book, a perpetual lie detector, limited only by the imagination and abilities of its practitioners.
7 Given the complex nature of the earth, no scientist makes an observation, suggests a hypothesis or develops a theory alone. Everyone's work relies on the work of others who have gone before. Even Isaac Newton, whose law of gravity has withstood the test of time, noted “If I have seen further it is by standing on the shoulders of Giants”.
The Characteristics of Good Science Good scientific explanations follow basic principles like those summarized below. Scientific explanations are tentative and How to Do Bad Science can and do change. Early attempts to determine the age of Attack the scientist, not Earth were based upon erroneous assumptions and estimated the science : Science the age of the planet to be a few million years old. With the doesn't advance based on advent of radiometric dating methods scientists calculated that personalities of the scientists Earth formed approximately 4.6 billion years ago. but on verification of facts and observations. Scientific explanations are based on empirical observations or experiments. For example, the direction and rate of flow of Argue from authority: Just groundwater in cave systems can be established by injecting because you are important non-toxic colored dyes at one location and then monitoring doesn't make you right. flow at several points downslope from the source. The data obtained from such analyses should be reproducible by others. Post hoc, ergo propter hoc: "it happened after so it Scientific explanations should be predictable and testable with was caused by" - confusion successful hypotheses. The daily weather forecast is a common of cause and effect. Just example of the use this rule. Meteorologists use their because day follows night knowledge of how air and moisture circulate through the does not mean that days are atmosphere to predict short-term changes in weather patterns. caused by nights.
Scientific explanations may be limited by available technology Poor Statistics: Choose a and new technologies can lead to new fields of inquiry. For sample size that is too small example, prior to the invention of the telescope, knowledge to be representative or use a about Earth's position in space was based upon observations biased sample. made with the naked eye. Astronomers such as Galileo used some of the first telescopes to identify perturbations in planetary orbits that would result in the hypothesis that the Sun, not Earth, was the center of the solar system.
Science cannot answer all questions. Questions that center on ethics or theology often have more to do with cultural or social norms than scientific concepts. Recent concerns about the potential for cloning humans can be separated into two distinct questions, one is scientific the other ethical. Can we clone humans? is a scientific question and the current answer is No, but research suggests that a future response could be Yes.
8 Should we clone humans? is an ethical question. If the answer is No, we may never clone a person even if the scientific knowledge exists to do so.
A valid scientific hypothesis offers a well-defined natural cause or mechanism to explain the occurrence of a natural event. For example, scientists who study earthquakes recognize a clear relationship between the amount of movement on fractures in Earth's crust and the size of earthquakes. Scientific analyses are discussed openly at conferences and published in journals so all ideas may be exposed to criticism or support from other scientists. Scientific journals require that articles are reviewed by other scientists before publication. This peer review process ensures that published research is original and adds to the body of scientific information.
Poor scientific reasoning rarely reaches a public forum because of the checks and balances inherent in the scientific method. However, sometimes hypotheses are unveiled in the media before they can be rigorously tested by others. Unfortunately, with further analysis, some of these ideas may be proven wrong prompting increased skepticism with the scientific method and scientists in general. The following cases include an example of correctly using a series of observations to support a novel hypothesis for the extinction of the dinosaurs and two examples of hypotheses that were not supported by the majority of scientists but that nonetheless received widespread publicity.
Asteroid Collisions with Earth Approximately 20 years ago, a team of scientists led by the father-son pair Luis and Walter Alvarez suggested that the extinction of the dinosaurs was caused by a collision between the Earth and an asteroid (Fig. 3) or comet 65 million years ago. Their hypothesis was based on several observations made Figure 3. The asteroid by themselves and other scientists: Gaspra viewed from the Galileo spacecraft, October 1. Dinosaurs died out relatively suddenly 65 million years 1991. The asteroid is ago. approximately 29 2. The extinction occurred everywhere at the same time. kilometers (18 miles) 3. The rare element iridium is present in unusually high across. Image courtesy of NSSDC photogallery. concentrations in rock layers 65 million years old worldwide.
9 4. Iridium is found in extraterrestrial bodies such as meteorites and asteroids. It is still a rare element in these bodies but it is more concentrated than on Earth.
The Alvarez hypothesis was that the impact generated so much debris that it blocked incoming sunlight for several years. Vegetation died in the absence of sunlight, resulting in the deaths of plant-eating dinosaurs. Carnivorous dinosaurs also died out when their prey, the herbivores, died. Recent geophysical exploration has discovered a possible impact site (Chicxulub Crater) in the Yucatan Peninsula, Mexico. The crater is in rocks that are older than the impact event and is covered by rocks that are less than 65 million years old. The crater is much larger than the asteroid or meteor that was responsible for its formation. It is over 300 km across, falling somewhere between West Virginia and South Carolina in total area.
Bad Science Scientists who don't engage in peer review to evaluate their research may be discredited if their results can't be reproduced by others. Alternatively, occasionally hypotheses receive publicity before they have had an opportunity to be critically reviewed by experts. Two recent examples of very public failed hypotheses are given below.
• Cold fusion: March 23, 1989: Researchers (Stanley Pons and Martin Fleischmann) at the University of Utah announced that they had used a simple, low-cost experiment to achieve a controlled nuclear fusion reaction for more than 100 hours in a small glass flask (cold fusion). The report prompted hope of a cheap, clean future energy source but their hypothesis: that a chemical reaction in a beaker of heavy water generated excess energy, has not been supported by scientists at other institutions.
• Midcontinent earthquake and tidal forces: December 3, 1990 - Date proposed by self-proclaimed climatologist and businessman Iben Browning for an earthquake on the New Madrid fault zone, southeast Missouri. New Madrid was the location for a series of major earthquakes over a three- month span from December 1811 to February 1812 (sometimes called the Mississippi Valley earthquakes). Browning’s hypothesis, that tidal forces could trigger another big earthquake on the fault zone, generated media
10 interest and caused local schools to close but was widely disputed by earthquake specialists. Nothing happened on the fateful day.
Think about it . . . 1. Use the first letter of each of the key characteristics of good science to create a mnemonic (memorization). Create a sentence composed of words that begin with the initial letter of each term. 2. Create a simple concept map that illustrates the characteristics of good science. 3. How did Lewis and Clark use the scientific method to make a crucial decision on which way to go during their exploration of the Missouri River? Examine the problem at the end of the chapter.
Science & Society
• A basic knowledge of Earth science is necessary for citizens to make informed choices about how they interact with their local, national, or global environment. • Earth scientists protect people and property from natural hazards but must also protect the environment from short- sighted human activities that have the potential to alter nature. • We rely on Earth to supply us with the all our basic resources. Earth science provides us with information on the distribution and quality of mineral and energy resources essential for maintaining or improving our quality of life. • Global-scale threats to the future of humanity require that we understand the complex workings of all aspects of the Earth system and the time scales on which they operate.
Why should you care about science, and Earth science in particular? Most of us are removed from the process of science. (How many scientists do you know?). If we think of science at all it is through the mirror of technology. Would you support initiatives that increase or decrease government funding for scientific research? This is not a question of science, but a question about the role of science in society.
11 Past experiences have convinced some people that they will never understand science whereas others may view the study of Earth Science or the environment to be irrelevant in this technologically-rich world. Many people are understandably bewildered by media reports that portray battling teams of scientists, each presenting opposing explanations for complex scientific problems. If the experts cannot agree they reason, how can I be expected to make a decision? Finally, even if we understand environmental problems, we are often frustrated by the apparent inability of those responsible to do anything about them. This can range from simple individual actions (Why doesn't my neighbor recycle?) to issues of corporate responsibility (Why do companies produce air pollutants?).
How can we become enlightened citizens, capable of identifying problems and participating in their solution? We Never doubt that a small will suggest a simple three-step process: know, care, act. group of thoughtful, committed citizens can • Know: The first step requires that we take responsibility change the world. Indeed, for our world by learning about how it works. it is the only thing that • Care: We are part of a society that works best when we ever has. care about how our actions will affect others at a range of Margaret Mead scales. But we should also be aware of how we will be affected by the actions of others. Think globally but act • Act: Do something. Make your opinion known. Go to a locally. town meeting, write a letter to your local paper, contact Rene Dubos your congressperson or senator, vote.
Earth scientists have several roles to play in modern society. These roles have become more crucial as global populations climbed to over 6 billion people in 2000 with 78 million more added each year. We are concerned about protecting life and property from the dangers of natural hazards, obtaining sufficient natural resources to maintain or improve our standard of living, and protecting the health of the natural environment. A final more comprehensive goal, ensuring the future of humanity, has recently received increasing attention as we glimpse a future where climate is impacted by human actions and where we recognize the global-scale devastation that may result from a potential meteorite or asteroid impact.
Natural Hazards as Facts of Life Scientists play a role in determining the potential risks from natural phenomena that may harm people and damage property. Natural processes such as earthquakes, landslides,
12 Figure 4. An example of a map illustrating areas at risk in the U.S. from one of six natural hazards. Click on the maps to view expanded versions with descriptions at the USGS hazards website. Go to www.usgs.gov/themes/ hazards.html to review all the maps.
flooding, volcanic eruptions, tornadoes, and hurricanes are considered hazards when they occur in populated areas. The detailed study of hazards in one area can help predict the potential risks elsewhere. Scientists used the information they learned from investigations of the 1980 Mt. St. Helens eruption to make accurate predictions of the size and timing of the 1992 eruption of Mt. Pinatubo in the Philippines (see Fig. 4). Average annual cost of The effects of some of these phenomena can be partially offset U.S. natural by technological advances: disasters: • Weather satellites are used to track hurricanes and predict $50 billion landfall sites allowing timely evacuation of residents (Fig. 5); • Doppler radar stations have more than doubled the advance warning of tornadoes; • Networks of stream gauges are used to monitor stream flow and predict the magnitude and timing of floods allowing emergency construction of levees and evacuation of residents; • Areas at greatest risk from earthquakes have strict building codes designed to ensure that buildings, although damaged, will remain standing when the shaking subsides; • Ongoing volcanic activity can be monitored by satellites to determine the timing and location of eruptions and redirect aircraft out of the path of the cloud of volcanic debris.
The principal advantage of technology is in providing safety to people living in areas at risk of natural hazards. Human beings are unlikely to be able to stop volcanoes from erupting or to
13 banish earthquakes. We can do little to prevent huge property losses associated with hazards but the use of technology can help save lives. Unfortunately, our faith in artificial structures such as stream levees often prompts increased development in areas at risk from hazards, ultimately resulting in greater damages when disaster strikes.
We can either attempt to prevent natural hazards from occurring or recognize that they will happen and adjust our lifestyles to deal with them. Hazards such as volcanic eruptions, large earthquakes, hurricanes, and tornadoes are sufficiently infrequent and extreme that we cannot prevent their occurrence. However, we can make adjustments that will minimize their impact through careful land use planning, the enforcement of building codes and the purchase of insurance policies. These steps ensure that areas at risk are not developed, key structures are built to withstand the hazard, or that funds Figure 5. Hurricane Fran are available to repair damages following a hazardous event. approaching the Atlantic Floods and landslides are clearly linked to streams and slopes, coast, September 1996. Fran allowing scientists to make local alterations to the environment made landfall along the coast in the hope that future hazardous events can be avoided. of North Carolina with wind Building levees to contain rising streams or reservoirs to store speeds of over 190 km/hr. floodwaters can locally diminish or eliminate flooding. Adding Image from Goddard Space better slope drainage or retaining walls can reduce landslide Flight Center's Public Photographic Image Retrieval frequency. However, we should be aware that any alteration of System (PPIRS). a natural system has the potential to cause unanticipated changes. For example, building a levee may reduce flooding locally but actually increase the flood risk downstream where the stream is in its natural state.
In assessing the risks associated with natural hazards, geologists must try to answer several questions: How often do such hazards occur? How large an area will be affected? How grave is the risk to people and property? What actions can be taken in both the short and long term to prevent some of these events or lessen their impact? Determining the correct answers to these questions requires knowledge of earth processes, the character of the landscape, the type and distribution of rocks underlying a region, and their physical and chemical properties.
Earth's Economic Resources Our lifestyles are supported by the use of natural resources. Basic resources such as water and soil vary in availability and quality around the globe. These essentially renewable resources are vital to food production and have to be carefully managed
14 Figure 6. Homestake mine, Lead, South Dakota. Homestake is the longest operating gold mine in the United States. Opened in the last century, the mine produces gold from a surface pit (pictured here) and from shafts drilled thousands of meters below the ground surface. to support future populations. Nonrenewable resources such as metallic minerals (Fig. 6) and fossil fuels are used most heavily by the more affluent societies of developed nations such as the countries of North America, Europe, and the Pacific Rim. However, the rapidly expanding economies of China and India have the potential to place much greater demands on global mineral and energy supplies. Together these two nations account for a third of the world's population.
Geologists must determine: Are there are sufficient resources Proportion of world to support the growing global population? What steps can be gold production taken to preserve the most heavily exploited resources? How used in jewelry: can resources be mined safely and economically? To 85% successfully answer these questions requires that we explore ever more remote parts of Earth's surface, including rain forests, rugged mountain ranges, and the deep ocean floor. Area of the Pacific Earth scientists seek to establish the type, distribution, and age island of Nauru of rocks underlying a region to discover if they may host that will be metallic ores or contain oil, gas, or coal deposits. uninhabitable following The use of resources carries with it decisions about lifestyle. mining: 80% The way we live varies from nation to nation and is often dictated by culture. For example, the Amish use fewer resources on average than other Americans because of religious and cultural traditions. Nearly all human actions have an impact on Earth's resources. Individual actions such as turning on a light switch or pouring a glass of water involve relatively modest resource use and require little thought except in the most extreme conditions. However, multiply those actions a millionfold and we may see an example of the economics of supply and demand when prices rise as supplies dwindle. Increases in gasoline and natural gas prices in the U.S. are just the most recent examples of this phenomenon.
15 The Health of the Environment Energy and mineral resources must be either consumed or recycled. The consumption of these resources generates waste and pollution during extraction, refining, manufacturing, and marketing. The industrial pollution that was once proudly viewed as a by-product of economic growth is now largely a thing of the past. Pollution is still widespread but its effects are muted and much more subtle, hidden among reports of respiratory ailments and contaminated drinking water supplies.
Legislation ensures that the construction of large-scale facilities that have the potential to degrade the environment must be preceded by an analysis of how such features may affect the surrounding area. The analysis produces an environmental impact statement (EIS). The National Environmental Policy Act (NEPA) signed into law by President Richard Nixon on January 1, 1970, directed that an EIS be filed for all federal activities that would have bearing on the environment. The Act required the government to “use all practicable means . . . to create and maintain conditions in which man and nature can exist in productive harmony.” Environmental impact statements must be filed for federal projects such as the construction of dams, sanitary landfills, or nuclear power plants.
Human activities that involve the use of technology or the manufacture of hazardous materials inevitably lead to failures that are unanticipated and may endanger human life or natural ecosystems. For example, we have found a variety of ways to contaminate stream systems, three examples of which are briefly described below. • Lower Mississippi River, winter, 1963/1964. The pesticide endrin, used to protect cotton and sugar cane crops, was found responsible for killing millions of fish in the Lower Mississippi River. Too much pesticide was applied and then washed from the fields by rains and surface runoff. • Cuyahoga River, Cleveland, Ohio, June 1969. The Cuyahoga River burned for the third time when a section of the polluted waterway in downtown Cleveland was ignited by molten slag from a nearby steel mill. The river burned for 20 minutes, setting fire to an old bridge. Today the river has been largely restored and the area is now occupied by an entertainment district.
16 • Ashland oil storage tank, Pittsburgh, Pennsylvania, January 1988. The worst inland oil spill in U.S. history occurred when an oil storage tank collapsed, releasing 750,000 gallons of diesel fuel into the Monongahela and Ohio Rivers.
Environmental Impact Statements The NEPA directed that an environmental impact statement (EIS) be filed for all federal activities that would have bearing on the environment. The act required that an EIS had to be filed if a venture met three criteria: 1. The activity was a federal project; 2. The project was considered major, involving a substantial commitment of fiscal and human resources; 3. The project had a significant impact on the human environment. The terms "major," "substantial," and "significant" went largely undefined leaving the door open to hundreds of court challenges each year. The first challenge filed under the NEPA guidelines was Wilderness Society vs. Hickel (Secretary of Interior) and involved the environmental impact statement for the construction of the Trans-Alaska oil pipeline.
Environmental Impact Statement: Trans-Alaska oil pipeline 1968 Atlantic Richfield found the greatest accumulation of oil in North America along the northern coast (North Slope) of Alaska. 1969 A consortium of oil companies announce plans to build a 48-inch pipeline to carry North Slope oil over 800 miles to the tanker port of Valdez on Alaska’s southern coast. Initial plans called for pumping heated oil through a buried pipeline. A government study found the heated oil would melt surrounding permafrost, leading to damage to the pipeline and the Arctic ecosystem. 1970 March 26: The Wilderness Society, Friends of the Earth, and the Environmental Defense Fund challenged the consortium’s application for permits. One aspect of their objection was that a sufficient environmental impact statement had not been completed for the pipeline. 1971 January 13: The Department of Interior issued a 196-page-draft environmental impact statement that concluded that North Slope oil was essential for the nation’s economy; a pipeline across Alaska was the best way to transport the oil; and an elevated pipeline could be built with little environmental disruption. Congressional hearings featured environmental groups that were critical of the EIS, claiming it underestimated earthquake risk, overlooked potential problems with tanker traffic, and did not fully examine the option of an overland pipeline through Canada. 1972 March 20: Final EIS was released as a 30-pound, six-volume text. 1974 January 23: Secretary of Interior Morton issued construction permits for the pipeline. 1977 July: First oil began to flow through the pipeline.
The pipeline itself has withstood the test of time reasonably well. There have been no major oil spills along the route and little negative effect on the wildlife of the area. The wreck of the Exxon Valdez and subsequent spill of 11 million gallons of oil in Prince William Sound are indirectly linked to the pipeline project. The potential for tanker problems was one of the reasons cited by the pipeline’s opponents. However, this must be balanced against the billions of gallons of oil that have been successfully delivered to U.S. oil refineries since the pipeline was built. 17 The Long-Term View: The Future of Humanity All of the issues discussed above are of local, regional, or national scale. All involve events that are significant on human time scales measured in hours to years. Taking a longer view at a global scale we can identify two processes that have the potential to affect everyone, everywhere, for decades and perhaps centuries into the future.
The impact of a large meteorite with Earth represents a global- scale natural hazard that has the potential to end all life as we know it or to devastate a continent-size area of the planet (Fig. 7). Concerns about such an impact have increased recently as scientists became aware that such events were more commonplace in the geological past than was previously thought. Although there is no shortage of ideas about how to stop a meteorite on a collision course with Earth, there is no existing mechanism for dealing with such an event.
Figure 7. Aorounga impact crater, Chad, 17 km across, was formed when a meteorite or asteroid collided with Earth. Image courtesy of NASA.
Global warming represents an alteration of global climate patterns as a result of human activity. An international panel of scientists has concluded that carbon dioxide and other gases of human origin have altered global climates over the last century. Higher concentrations of carbon dioxide are associated with climate intervals characterized by warmer temperatures. Warmer conditions have the potential to cause wholesale changes in natural systems around the world. Climate models suggest that an increase in the frequency of extreme weather events, a shift in the distribution of ecosystems, higher rates of species extinction, wider areas of tropical disease, and a rise in global sea levels are all possible with higher temperatures. The quality of life for future generations, not to mention the long-
18 term health of the environment, will depend upon the degree and rate of these changes. But these changes will also be influenced by future decisions to be made by the governments of the world's most populous nations and the actions of their citizens.
A program that attempts to address either of these issues would be both complex and expensive, requiring cooperation between many nations and potentially taking decades to complete.
Our Environmental Heritage, before 1899
• American concern for the environment can be traced back to the continent's earliest inhabitants. • Actions of European colonists resulted in land degradation and reduction of species habitat and led to early legislation to protect some favored species. • An appreciation for the land blossomed in the nineteenth century, prompting the creation of forest reserves and the earliest national parks.
Introduction to the Continent, pre-1780 Some of North America’s earliest inhabitants entered the continent by way of a narrow finger of land that joined Alaska and Siberia over 10,000 years ago at the close of the last great ice age. Much of the Northern Hemisphere was coming out of a deep freeze as ice sheets thousands of feet thick began to retreat toward the Arctic. The first Americans crossed what is now the floor of the Bering Sea and migrated southward in search of a warmer climate. Over the course of thousands of years these peoples differentiated into the native tribes that greeted European explorers such as Columbus, De Soto, and Coronado. The maximum population of pre-Columbian North America has been estimated as two million (approximately the population of Utah). Limited numbers muted the environmental impact of the continent's earliest residents. Although native philosophies encouraged stewardship for the land rather than exploitation for economic gain it is probable that Native American hunters were responsible for the extinction of some large animal species following the ice age.
19 Figure 8. A teepee ring in central Wyoming marks the location of a temporary settlement approximately 100 years ago. The ring of stones (~4 meters wide) held down the edges of a teepee. Small groups of European settlers, scattered along the continent’s eastern fringe in the seventeenth century, viewed the new lands as a threatening wilderness that contrasted with the tame, domestic landscapes of northern Europe. A passenger of the Mayflower viewed his new home as a “hideous and desolate wilderness” but the early colonists were not above a little creative advertising to lure others to the “particular beauty” of the wilderness that one could not view without "contentment." Population growth forced exploration inland, pushing the frontier westward. The transplanted Europeans began to develop a distinctive national identity that historian Frederick Jackson Turner would later suggest “came out of the forests and gained new strength each time it touched a frontier.”
Gradually a new perspective evolved - nature as a garden - that saw nature not as a threat but as a resource to be exploited. Forests and wetlands were converted to farmlands. Native species began to disappear as their habitats were destroyed or they were hunted to near extinction. Early settlers' descriptions of rivers teeming with fish and forests full of game leave little doubt that wildlife went into a steep decline after coming face to face with the colonists. Diminishing wildlife populations encouraged colonial governments to introduce closed hunting seasons before the end of the seventeenth century. However, the view of wildlife was heavily weighted in favor of "useful" animals (game suitable for hunting, e.g., deer) and against predators that were often targeted for extinction by bounty programs (e.g., wolves). Such policies remained in effect for the three centuries in many regions of the continent. In 1753, Swedish botanist Peter Kalm reported “. . . about sixty or seventy years ago [1680-1690], a single person could kill eighty ducks in a morning, but at present you frequently waited in vain for a single one . . . since the arrival of great crowds of Europeans, things are greatly changed.”
20 The early economy of the colonies was tied to agriculture but the vast expanse of available lands made the colonists poor stewards of their new land. The colonists’ relatively primitive agricultural methods typically began with the burning of virgin forests to create new farmlands. In Virginia and other southern colonies, crops such as corn and tobacco were cultivated in open rows with little ground cover, leading to erosion that stripped the topsoil from the fields. Soil was washed into streams, degrading water quality and destroying freshwater habitats. Such early environmental problems did not go unnoticed. George Washington, Thomas Jefferson (Fig. 9), Figure 9. Harpers Ferry, and James Madison all experimented with soil conservation West Virginia, and the strategies. Madison's rules for better care of the soil included: confluence of the Potomac (bottom) and Shenandoah don't plow shallow furrows, don't plow up and down the slope (top) Rivers viewed from of the land, and add manure to increase soil fertility. Maryland Heights. Thomas Jefferson considered the view "perhaps one of the Thoughts about the Land, 1780-1899 most stupendous scenes in nature . . . This scene is J.H. St. John de Crevecoeur's observations on nature in worth a voyage across the America were published in Letters from an American Farmer Atlantic." Of course, he in 1782. When Crevecoeur noted that Americans had “done the wasn't looking at this most in the least time of any people” he was recognizing the particular photograph. changes to the natural world as well as the progress from disparate colonies to a newly forged nation. Resource exploitation fueled the economy of the recently christened United States. Lewis and Clarke's trip up the Missouri River (1804-1806) opened the way for trappers and other settlers to push westward in search of furs or farmland. The destruction of northern forests kept pace with the westward migration of settlers. Nathaniel Shaler noted that flooding in the Ohio river system had increased because “a large part of the forest coating of the Ohio Valley has disappeared, and what remains is marked all over by the hand of man.” New York State passed legislation to create the Adirondack Forest Reserve in 1885 and the first national reserves (later to become national forests) were created in 1891.While miners were exploring for gold in the Black Hills (South Dakota) in violation of treaty agreements, the government was passing legislation to open up public lands for mining at bargain basement rates ($2.50 or $5.00 per acre) that still apply today.
Nature, in the form of the vast continent and its bountiful resources came to define the new America in contrast to the record of art and architecture that defined the Old World. Artist George Catlin, traveling on the Great Plains in 1832, first suggested the creation of a “nation's park” to preserve the
21 culture and associated bison of the Plains Indians. In lieu of the real thing, the citizens of Louisville, Kentucky, packed theaters to view the gradual unfurling of a mammoth panorama of the Mississippi River. Frederick Law Olmstead designed Central Park with Calvert Vaux in 1858, creating a welcome open space among New York's million residents. Olmstead was an early advocate for creating public parks as “the enjoyment of scenery employs the mind . . . gives the effect of refreshing rest and reinvigoration of the whole system.” Yellowstone, the nation's (and world's) first national park was designated by Congress in 1872, but only after it became clear that the land had little commercial potential.
Early naturalists like painter John James Audubon began to draw America's attention to the beauty in nature and man's impact on the natural world. It was a Vermont native, George Perkins Marsh (Fig. 10) who first thoroughly documented how human actions had harmed the environment. Marsh addressed the degradation of the land and rivers resulting from thoughtless logging practices before the Agricultural Society of Rutland County, Vermont, in 1847. Deforestation was so extensive in New England by 1840, that timber mills in Burlington, Vermont, had to import timber from Canada to maintain production. Marsh’s subsequent travels as a diplomat in Europe convinced him that “. . . man is everywhere a disturbing agent. Wherever he plants his foot, the harmonies of nature are turned to discords.” Henry David Thoreau's Walden, published in 1854, remains a classic of conservation literature. Thoreau (Fig. 10) recognized the dramatic changes in nature in the preceding centuries and anguished over the losses that had occurred, “When I consider what nobler animals have been exterminated here - the cougar, the panther, lynx, wolverine, wolf, bear, moose, deer, the beaver, the turkey, Figure 10. Henry David etc., etc. - I cannot but feel as if I have lived in a tamed, and, as Thoreau (far left), and it were, emasculated country . . . I wish to know an entire George Perkins Marsh, heaven and an entire earth.” wrote two of the most influential books on the state of nature of the nineteenth century. Thoreau's Walden is still widely read and Marsh's Man and Nature (1864) was the first book to give detailed examples of how human beings had altered nature. Images courtesy of Library of Congress.
22 Increasing numbers of people were drawn to join new organizations with the goals of protecting lands (Appalachian Mountain Club, Sierra Club), birds (American Ornithologist’s Union, Audubon Society), trees (American Forestry Association) and wildlife. Awareness of decreasing wildlife populations prompted the formation of several conservation organizations among hunters. Groups such as the New York Sportsmen’s Club, the Boone & Crockett Club, and the League of American Sportsmen recognized that restrictions were needed to prevent overexploitation of some game species.
Likewise Congress began to act to protect wildlife from commercial hunting operations. This was perhaps best exemplified by actions taken to prevent the extinction of the bison (buffalo). An estimated 30 million bison had originally roamed through most of the U.S. but westward expansion and widespread hunting had reduced the population to less than a thousand animals, most of which lived in the recently created Yellowstone National Park (Fig. 11). Congress passed the National Park Protective Act (1894) to prohibit hunting in national parks in an effort to prevent poaching of the remaining bison. A national campaign to protect bison was launched by William Temple Hornaday that would later (1905) result in the creation of wildlife refuges in Oklahoma and other western states to begin to rebuild the bison population.
Figure 11. Bison among hot springs, Yellowstone National Park, Wyoming.
Think about it . . . Read an abbreviated version of a speech given by George Perkins Marsh in 1847 (see end of chapter). What was Marsh concerned about over 150 years ago? How do these issues compare with modern environmental concerns?
23 Our Environmental Heritage, 1900-today
• An appreciation for the land blossomed in the nineteenth century, prompting the creation of forest reserves and the earliest national parks. • The second half of the twentieth century was marked by a growing concern for pollution of the environment at both regional and global scales.
Government and the Public Lands, 1900-1950 The federal government took increasingly active steps to preserve the environment during the last few decades of the nineteenth century. The next century began with passage of the Lacey Act, the first comprehensive national legislation to protect wildlife. Following on the heels of the Lacey Act, President Theodore Roosevelt issued an executive order to designate the nation's first bird reservation on Pelican Island, Florida, in 1903. This would be the first of nearly five hundred national wildlife refuges to be established by the federal government, from the tiny (0.6 acre) Mille Lac refuge (Minnesota) to the massive Yukon Delta site (19 million acres) in Alaska. Several state Audubon groups joined together to form the national Audubon Society (1905) a few years after the establishment of Pelican Island. What began as a group dedicated to studying and protecting birds has grown into an organization that today counts its members in the millions. Just eleven years later the passenger pigeon became extinct when the last bird (Martha) died in the Cincinnati zoo. Passenger pigeons had once been numbered in the billions, flying in massive flocks they made easy targets. Even the most prolific of species was vulnerable to the threat of extinction. Figure 12. Devils Tower, Wyoming, the nation's first national monument, created by Theodore Roosevelt in 1906.
President Benjamin Harrison created the nation's first forest reserves in 1891 but it would be Roosevelt who moved most aggressively to create new forest lands in the rechristened (1907) National Forests. There were over 150 million acres of national forest lands, almost exclusively in the western states, by the end of Roosevelt's tenure in the White House.
24 Roosevelt, the first conservationist president, would also create the first national monuments using the Antiquities Act (Fig. 12). A decade later the National Park Service was created to manage the growing number of parklands that would expand into the approximately 370 sites that exist today.
Roosevelt's initiatives were primarily concerned with resource conservation. His chief forester, Gifford Pinchot, summed it up this way, “. . . the object of our forest policy is not to preserve the forests because they are beautiful or the habitat of wild animals; it is to ensure a steady supply of timber for human prosperity. Every other consideration comes as Figure 13. John Muir (left) secondary.” and Teddy Roosevelt, Glacier Point, Yosemite Others viewed nature as an aesthetic resource that should be National Park. Image preserved simply because it looked good or represented a courtesy of Library of unique natural environment that would be lost with the Congress. intrusion of human beings. The chief advocate of this view was John Muir, a respected writer/naturalist and Sierra Club founder. Pinchot's pragmatic view of conservation collided with Muir's instinct for preservation over the fate of the Hetch Hetchy valley within Yosemite National Park. San Francisco sought to dam the valley to create a reservoir to alleviate future water needs. The city needed congressional approval because the site was within the boundaries of a national park. San Francisco was granted use of the valley after a contentious decade-long battle waged in the pages of the popular magazines and newspapers of the day. The debate over Hetch Hetchy would foreshadow conflicts in the second half of the century.
Figure 14. National forest lands, Black Hills, South Dakota
Conservation Becomes Environmentalism, 1950-today State and local governments sought ways to ensure a steady supply of water as populations of the dry western states increased during the twentieth century. An early step (1902) was the passage of the Reclamation Act to promote dam building in western states. Twenty years later the Colorado
25 Figure 15. Colorado River, from Dead Horse Point, Utah, (left); Glen Canyon Dam was completed on the river amid controversy in the 1960s (right).
River Compact was signed by seven western states (Wyoming, Colorado, Utah, New Mexico, Nevada, Arizona, California), allocating the waters of the Colorado River (Fig. 15) for future use in irrigation, hydroelectric power generation, and domestic water supply. Unfortunately, the agreement was signed during a period of heavier than normal flow, culminating in so much water being withdrawn from the river that it no longer reaches its delta in northern Mexico.
Debate over future use of water in the Colorado River basin ignited a second national debate on dam construction when the Bureau of Reclamation sought to build a dam in Dinosaur National Monument, and later near Grand Canyon National Park. Both projects were eventually scrapped after widespread opposition but the Glen Canyon Dam (Fig. 15) near Page, Arizona, was built in their place drowning tens of miles of lightly-visited canyons.
The consequences of technology and industrialization became realized in the more densely populated regions of the U.S. Smog became a daily nuisance in California and industrial air pollution was a fact of life in much of the Midwest and Northeast. Deaths were tied to toxic air pollution in Donora, Pennsylvania, and London, England (approximately 5,000 on one weekend in 1952). Later scientific studies would link industrial emissions to acid rain that contaminated lakes hundreds of miles downwind in the Adirondack Mountains of New York. Conservation organizations that had been concerned with public land issues were being transformed into environmental groups focusing on the consequences of pollution.
Rachel Carson's Silent Spring (1962) warned of the perils of pesticide use (especially DDT which was later banned in the U.S.). Carson was attacked by a chemical industry bent on promoting “better living through chemistry” but public opinion and, eventually, government agencies, came out in her favor
26 Figure 16. Like many sites, this chemical dump in northern Ohio has been cleaned up and replaced by green fields. Image courtesy of David Wertz.
and people began to be more apprehensive about the quality of their drinking water. To drive home the point that not all progress was wholly beneficial, 1969 featured two dramatic environmental calamities. The Cuyahoga River ignited and burned as it flowed through, Cleveland, Ohio, and millions of gallons of oil were spilled from a leaky well off the coast of California, polluting the beaches of neighboring Santa Barbara.
However, the next year things began to look up. President Richard Nixon signed the National Environmental Policy Act into law on January 1, 1970, marking the first of an impressive series of environmental laws to be created in the following decade (e.g. Clean Water Act, 1972; Endangered Species Act, 1973; Safe Drinking Water Act, 1974; Fig. 16). A few months later the nation became swept up in the first Earth Day, when millions of people participated in workshops, rallies, and celebrations of the natural environment.
Rene Dubos' maxim “Think globally, act locally” decorated bumper stickers everywhere as our impact on the planet became clearer in the 1980's and 1990's. Fifty years after Du Pont introduced Freon, British scientists would publish the first description of a hole in the ozone layer over Antarctica (1985), demonstrating the price we sometimes pay for technological advances. The next year, a nuclear accident at Chernobyl in the Soviet Union spread radioactive contamination far beyond the boundary of its host nation and illustrated how local environmental problems were becoming regional or global in scale. Such catastrophic events provided the images and examples that environmental groups required to convince a wary public of the need for stronger regulations to protect the increasingly crowded environment.
Evidence that significant positive change can occur was provided by the Montreal Protocol, an international
27 agreement signed in 1987 and revised in later years, that banned the chemical agents responsible for destruction of the ozone layer over Antarctica. Recent attempts (Earth Summit, 1992; Kyoto Conference, 1997) to forge alliances to offset the threat of global warming have set deadlines that must be met later this decade. It is not yet apparent if the political establishment in key nations has the will to enforce the regulations needed to meet these optimistic goals.
The global population topped six billion people in 1999 and will add another billion by the end of this decade. Earlier warnings of massive starvation have proven unfounded but concern remains about how to feed more and more people using the finite resources of our planet. As poorer nations set their sights on the material goods and basic resources (clean water, air) found in more affluent countries, many are wondering if there will be enough of everything to go around. A few years ago a group of distinguished scientists issued a Warning to Humanity, and suggested that we should (1) protect the planet by reducing activities that cause environmental harm and become better managers of Earth's resources and, (2) change the culture that leads to environmental degradation by reducing population growth, eliminating poverty, and promoting sexual equality.
To protect Earth we must understand the physical environment as defined by the laws of nature. However, we must work within the cultural perspective of our time in striking a balance between science and economics and political forces. History shows that committed individuals can change the way we interact with our planet. Our perspectives have changed dramatically in the last four hundred years. The early colonists viewed wilderness as dangerous while we protect it, preserving it through careful stewardship for future generations where wild, natural spaces will be increasingly rare.
Think about it . . . Do you agree or disagree with the following quote by Harlan Cleveland: "This is the first generation in the history of the world that finds that what people do to their natural environment is maybe more important than what the natural environment does to and for them."
28 The Science of Global Change
• Global change involves changes in the Earth's climate related to changing conditions in the atmosphere, hydrosphere, biosphere and solid earth. • Thousands of scientists worldwide are working to better understand the linkages between the different components of the Earth system and how they are affected by changing climate. • The U.S. government spent nearly $2 billion on climate change research that focused on seven broad topics and involved scientists in chemistry, physics, geology, and biology as well as workers in a variety of other fields.
Global change involves the analysis of changes in Earth's climate over time. These changes have influenced all elements of the Earth system throughout the geological past and will continue to have a significant impact in the future. Some of these changes will occur gradually, on the time scale of the planet, perhaps taking thousands of millions of years. Others have the potential to occur on human time scales measured in years or decades. Some changes will be relatively benign whereas others may result in the catastrophic transformation of the climate system.
The climate system is linked to or influenced by almost all processes that occur on Earth (Fig. 17). The science of global change requires that we understand not only how Earth works but also how the different elements of the Earth system are interwoven and how they impact each other. Consequently, scientific research on global change is the definition of "big science," it involves researchers around the world working on thousands of different projects, all contributing a piece to a Figure 17. Global cloud much larger puzzle. Research on global change within the U.S. cover, sea surface involves scientists at numerous government agencies, temperatures, and land surface temperatures universities, corporations, and research centers. The U.S. during spring. Clouds are present over the equator and clear skies over the tropics. Sea and land temperatures decrease toward higher latitudes. Image courtesy of the Space Science and Engineering Center at the University of Wisconsin.
29 government budgeted nearly $1.8 billion for climate change research initiatives in 2000. A little under half of these funds supported scientific research with the remainder going to space-based observation programs.
The objectives of research on global change span a wide range of disciplines including chemistry, biology, geology, physics, economics, and geography. The U.S. Global Change Research Program divides research objectives into seven broad categories briefly described below. Each objective involves hundreds of scientists examining many different problems that will all contribute to our understanding of global change. Each team of scientists must make a research plan, collect data, make observations, draw conclusions, present their work at professional meetings, and write technical articles during the term of their research. Scientists seek to piece together a story about past and future climate change by reading literally thousands of publications and synthesizing hundreds of ideas. This represents a lot of hard work and the process moves slowly forward in careful increments. This is the nature of science.
Global Change Research Objectives Associated with U.S. Government Agencies Gov. YR2000 Comp. Global Eco- Population Ancient Earth's Global Agency Budget of the Carbon systems & Global Climates Climate Water ($M) Atmos. Cycle Change System Cycle DoA 89 •• • NOAA 70 •• • • • • DoE 125 •• • • • • DoHHS 40 • DoI 27 •• EPA 23 •• NASA 261 •• • • • NSF 187 •• • • • • • Smithsonian 7 •• • • • •
$829 million was budgeted for scientific research (Year 2000 budget column), most going to support projects funded by NASA, NSF and DoE. Abbreviations: DoA, Department of Agriculture; NOAA, National Oceanographic and Atmospheric Administration (and Department of Commerce); DoE, Department of Energy; DoHHS, Department of Health and Human Services; DoI, Department of Interior; EPA, Environmental Protection Agency; NASA, National Aeronautical and Space Administration; NSF, National Science Foundation; Smithsonian, Smithsonian Institution.
We will introduce several of the key concepts of global change below but we will return to them in greater detail as we move through The Good Earth. This is fitting because it is a topic that you will see and hear more about in the years ahead and it
30 gives us an opportunity to look over the shoulders of the researchers to see the scientific process in action.
Composition of the Atmosphere The concentrations of key gases in the atmosphere has changed as a result of human activities including the use of fossil fuels and the production of emissions from industrial and agricultural operations. Natural variations in the composition of the atmosphere are a consequence of volcanic eruptions, solar radiation, and the normal functions of weather systems and the biosphere.
Key Questions • How will the changing composition of the atmosphere influence harmful incoming solar radiation? • Will airborne pollutants serve to cool or warm the lower atmosphere and how long will such substances remain in the air?
What We Need to Know • Data on the composition of the atmosphere at different altitudes from surface stations, balloons and airborne monitors, and satellites. • The distribution, degree, and character of pollutants and the influence of local, regional, and global weather systems.
The Carbon Cycle The concentration of carbon dioxide in the atmosphere is linked to the global carbon cycle. The oceans and the land system store carbon dioxide that is not held in the atmosphere. Understanding the connections between the sources, where carbon is released, and sinks, where carbon is absorbed, and how they are influenced by human activity will allow us to identify the most appropriate mitigation efforts. The capacity of some natural sinks is poorly understood, making it difficult to accurately estimate the future potential for carbon storage at these sites.
Key Questions • What is the fate of carbon dioxide produced by human activity? • How will human production of carbon dioxide change in the next century?
31 What We Need to Know • Measurements of the relative proportions of carbon dioxide absorbed by land and ocean sinks. • How much carbon emissions can be reduced through improved technology and how much emissions will increase from increasing populations.
Ecosystems The biosphere will be influenced by climate changes. Scientists are studying how different ecosystems respond to such changes. The scale of climate change will strongly influence the impact on ecosystems. We must determine how large an area will be affected and how fast the changes will take place. We rely on the managed biosphere to provide food resources for almost all of the world's population. Our ability to feed the world's peoples may be determined by how agricultural resources respond to climate change.
Key Questions • How will land use patterns change, including the character of land cover, the operation of local ecosystems, and water availability? • How will the biosphere respond to changes in atmospheric quality and composition? • How will ecosystems respond to multiple simultaneous stresses?
What We Need to Know • Our degree of reliance on natural and managed land use systems and how that will change with variations in climate. • The feedback mechanisms between atmosphere, biosphere, hydrosphere, and soils. • How plants and animals respond not only to temperature changes but also changes in water availability, atmospheric gases, and soil composition.
Population and Global Change The linkage between human activities and changes in natural systems needs to be fully comprehended to identify potential changes that might result. The future will lead a to a near- doubling of global populations and a general increase in consumption but such changes will not be evenly distributed worldwide. Some regions may experience extreme changes in
32 both climate and resource use and we need to understand the potential economic and social consequences of such changes. Humanity has caused widespread alteration of the land surface and the composition of the atmosphere yet we are dependent on the most basic natural resources (land, air, water) for survival.
Key Questions • How sensitive are different social systems to potential changes in climate and their consequences?
What We Need to Know • The impact of different social systems on their environments and the range of options available to ensure a healthy future. We need data on population growth, resource consumption patterns, land use, social support structures, rate of technological change, and economic development.
Ancient Climates We can use the record of global change in the geological past to identify the natural variability in the Earth system. Scientists attempt to strip away the natural variability in climate patterns to recognize the influence of human activities and therefore get a better perspective on the potential rate and range of changes that may occur and how we might combat their negative consequences. A number of different components of the natural environment can be used to learn about past climates.
Key Questions • How much natural variation in climate is possible and how rapidly can such changes occur? • What are the potential triggers and signals of such changes? Are there some specific thresholds or limits for catastrophic change?
What We Need to Know • Data from the natural environment on past climates by analyzing a variety of proxy climate indicators such as tree rings, coral growth patterns, ice cores, and sediment records from lakes and oceans. • The forcing factors that cause climate to change. We are especially susceptible to rapid climate changes that occur over years or decades. What causes such dramatic short- term changes?
33 Earth's Climate System Much of our cultural and physical characteristics as nations are defined by climate. Short-term climate fluctuations such as El Nino may disrupt "normal" climate patterns for a few years and have negative consequences for some regions (natural hazards, agricultural loses) while producing benefits for others (lower heating costs, agricultural gains). The resulting economic losses or gains may be measured in billions of dollars.
Key Questions • How do we understand the mechanisms of regional and global climate patterns?
What We Need to Know • Monitor key elements in these systems to identify the onset of climate events to allow the recognition of characteristic patterns that can be used to predict future events.
The Global Water Cycle Water represents perhaps the most important basic resource on the planet. Its presence or absence is dependent upon global climate systems and its quality is closely linked to human activity. However, the linkage between weather and climate ultimately determines how much water is supplied to a given region by precipitation.
Key Questions • How is the availability of water on land related to the global climate cycle? • How would a change in climate impact the evaporation, transport, and precipitation of water in regional weather systems? • How will natural and managed systems be affected by changes in water availability?
What We Need to Know • The factors that lead to extreme events that will result in too much or too little water being delivered at time scales of hours to decades. • The route of water through the global hydrologic cycle, especially the transport of water through the atmosphere. • What social systems are in place to address water-related problems?
34 Summary
1. Define the terms geology and environment. Geology – the study of the origin, composition and structure of the Earth and the processes that shape its surface; Environment – the physical and chemical characteristics of the world in which we live and the cultural conditions that influence our interaction with Earth.
2. What factors influence the decisions we make about the environment? The physical and chemical factors that can be measured and other social and cultural criteria including those that are subjective.
3. How does the scientific method work? The scientific method involves using observations to form testable hypotheses; a successful hypothesis becomes a theory. A hypothesis that the extinction of the dinosaurs was caused by the impact of the asteroid with Earth is linked to a crater in Mexico. Inaccurate hypotheses often do not follow the traditional procedure for formulating scientific ideas.
4. What is the role of Earth scientists in modern society? Evaluating natural hazards: Scientists determine the potential risks from natural phenomena that may harm people and damage property. The effects of some of these phenomena can be partially offset by technological advances. Managing resources: Human existence requires the use of basic resources (water, soil, minerals, oil, coal) which must be managed to ensure sufficient future supply and minimal environmental degradation during exploitation. The health of the environment: Human activities that involve the use of technology or the manufacture of hazardous materials inevitably lead to failures that are unanticipated and may endanger human life or natural ecosystems. The future of humanity: Scientists must evaluate potential global-scale problems associated with meteorite impacts or changes in Earth's climate system.
5. How has America's environmental heritage relied on the actions of individuals and citizens’ groups? American concern for the environment can be traced back to the continent's earliest inhabitants. Actions of European colonists resulted in land degradation and reduction of species habitat and led to early legislation to protect some favored species. An appreciation for the land blossomed in the
35 nineteenth century, prompting the creation of forest reserves and the earliest national parks. The second half of the twentieth century was marked by a growing concern for pollution of the environment at both regional and global scales.
36 Lewis and Clark and the Scientific Method
June 3, 1805 The Lewis and Clark expedition, following the Missouri River west toward the Rocky Mountains, arrive at the junction of two rivers. The natives of the area had told the explorers that they would soon arrive at a series of falls and rapids (the Great Falls of the Missouri River) but had not given them any information about which fork in the river to follow. Lewis wrote in his journal: “An interesting question now to be determined, which of these rivers is the Missouri . . . to mistake the stream at this period of the season . . . and to ascend such stream . . . and then be obliged to return and take the other stream would not only lose us the whole of this season but would probably so dishearten the party that it might defeat the expedition altogether . . .”
Lewis and Clark decided the only option was to investigate both rivers in the hope of finding evidence that would allow them to predict which was the Missouri River. Two teams of three men each are sent to spend the day investigating each river.
1. What observations could they have made to help in their decision?
The team that investigated the North Fork reported that the waters flowed “in the same boiling and rolling manner which had uniformly characterized the Missouri throughout its whole course so far.” At this point all members of the expedition agreed on which one of the rivers was the Missouri.
2. Which river do you think they chose? a) The South Fork b) The North Fork
However, Lewis and Clark themselves were still not convinced. They realized that a mistake might have severe consequences for their exploration and decided to do some further investigation. The next day, Clark and Lewis each led teams of six up the South and North Forks, respectively. Clark took three days and traveled 40 miles upstream; Lewis spent five days on his reconnaissance, which reached 60 miles upstream.
3. What additional observations could they have made to aid in their decision?
On June 11, the Lewis and Clark expedition ascended what they determined must be the Missouri River and two days later, Lewis roving ahead of the rest of the expedition, encountered the Great Falls of the Missouri, confirming that they had made the right decision. Which river did they ascend?
37 George Perkins Marsh (1801-1882) Read a much abbreviated version of a speech (below) given by George Perkins Marsh to the Agricultural Society of Rutland County (Vermont), September 30, 1847. The text of the original presentation is available at the Library of Congress History of Conservation site.
Selections from an address delivered before the Agricultural Society of Rutland County (Vermont), September 30, 1847, by George Perkins Marsh
America offers the first example of the struggle between civilized man and barbarous uncultivated nature. In all other primitive history, the hero of the scene is a savage, the theatre a wilderness, and the earth has been subdued in the same proportion, and by the same slow process, that man has been civilized. In North America, on the contrary, the full energies of advanced European civilization, stimulated by its artificial wants and guided by its accumulated intelligence, were brought to bear at once on a desert continent, and it has been but the work a day to win empires from the wilderness, . . . This marvelous change . . . has converted unproductive wastes into fertile fields, and filled with light and life, the dark and silent recesses of our aboriginal forests and mountains.
In purely savage life, the wants of man are supplied by the destruction of the fruit, or plant, or animal, which clothes or feeds the human beast of prey, . . . takes no thought for the reproduction of that which he improvidently consumes, but trusts implicitly to the bounty of spontaneous nature to supply the demands which the appetites and needs of her own children have created. Civilization begins with arrangements for securing the continued and regular supply of man's two great physical wants, food and clothing . . . The arts of the savage are the arts of destruction; he desolates the region he inhabits, his life is a warfare of extermination, a series of hostilities against nature or his fellow man . . . Civilization, on the contrary, is at once the mother and the fruit of peace. Social man repays to the earth all that he reaps from her bosom, and her fruitfulness increases with the numbers of civilized beings who draw their nutriment and clothing from the stores of her abundant harvests. The fowls of the air, too, and the beasts of the field, find in the husbandman a cherishing friend . . . Savage man then is the universal foe, both of his own kind and of all inferior organized existences, an incarnation of the evil principle of productive nature; civilization transforms him into
38 a beneficent, . . . and a protective influence, and makes him the monarch not the tyrant of the organic creation.
Men now begin to realize what, as wandering shepherds, they had before dimly suspected, that man has a right to the use, not the abuse, of the products of nature; that consumption should everywhere compensate by increased production; and that it is a false economy to encroach upon a capital, the interest of which is sufficient for our lawful uses.
The progress of agriculture, within the last half century though great in itself and full of future promise, has been but a tardy movement, in comparison with the swift advancement of the mechanic arts (technology). The steamboat, the locomotive, the power loom, and the power press, have all been brought into use since the beginning of the present century, and what a revolution have they wrought upon the face of the globe! . . . The mechanic arts are eminently democratic in their tendency. They popularize knowledge, they cheapen and diffuse the comforts and elegancies as well as the necessaries of life, they demand and develop intelligence in those who pursue them, they are at once the most profitable customers of the agriculturist, and the most munificent patrons of the investigator of nature's laws.
There are certain other improvements connected with agriculture, to which I desire to draw your special attention. The increasing value of timber and fuel ought to teach us, that trees are no longer what they were in our fathers’ time, an encumbrance. We have undoubtedly already a larger proportion of cleared land in Vermont than would be required, with proper culture, for the support of a much greater population than we now possess, and every additional acre . . . deprives succeeding generations of what, though comparatively worthless to us, would be of great value to them.
The inconveniences resulting from a want of foresight in the economy of the forest are already severely felt in many parts of New England, and even in some of the older towns in Vermont. Steep hill-sides and rocky ledges are well suited to the permanent growth of wood, but when in the rage for improvement they are improvidently stripped of this protection, the action of sun and wind and rain soon deprives them of their thin coating of vegetable mould (top soil), and this, when exhausted, cannot be restored by ordinary husbandry (farming practices).
39 On the other hand, where too large a proportion of the surface is bared of wood, the action of the summer sun and wind scorches the hills which are no longer shaded or sheltered by trees, the springs and rivulets that found their supply in the bibulous (thirsty) soil of the forest disappear, and the farmer is obliged to surrender his meadows to his cattle . . . and sometimes even to drive them miles for water. (Rains) no longer intercepted and absorbed by the leaves or the open soil of the woods, but falling everywhere upon a comparatively hard and even surface, flow swiftly over the smooth ground, washing away the vegetable mould (top soil) as they seek their natural outlets, fill every ravine with a torrent, and convert every river into an ocean. The suddenness and violence of our freshets (floods) increases in proportion as the soil is cleared; bridges are washed away, meadows swept of their crops and fences, and covered with barren sand, . . . and there is reason to fear that the valleys of many of our streams will soon be converted from smiling meadows into broad wastes of shingle and gravel and pebbles, deserts in summer, and seas in autumn and spring.
The changes, which these causes have wrought in the physical geography of Vermont, within a single generation, are too striking to have escaped the attention of any observing person . . . The signs of artificial improvement are mingled with the tokens of improvident waste, and the bald and barren hills, the dry beds of the smaller streams, the ravines furrowed out by the torrents of spring, . . . seem sad substitutes for the pleasant groves and brooks and broad meadows of his ancient paternal domain. If the present value of timber and land will not justify the artificial re-planting of grounds injudiciously cleared, . . . in our future husbandry (farming practices) a more careful selection should be made of land for permanent improvement. It has long been a practice in many parts of Europe, as well as in our older settlements, to cut the forests reserved for timber and fuel at stated intervals. It is quite time that this practice should be introduced among us. In many European countries, the economy of the forest is regulated by law; but here, where public opinion determines, or rather in practice constitutes law, we can only appeal to an enlightened self-interest to introduce the reforms, check the abuses, and preserve us from an increase of the evils I have mentioned.
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