SCI207 Wk3 Ashford university Sustainable Living Guide Contributions

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Term is bottom trawling.

Week 3 - Assignment 2

Prior to beginning work on this assignment, please review Chapter 5: Water, in Turk and Bensel’s Contemporary Environmental Issues textbook (2014). The purpose of this assignment is twofold: first, to enable you to explore a term (concept, technique, place, etc.) related to this week’s theme of sustaining our water resources; second, to provide your third contribution to a collective project, the Class Sustainable Living Guide. Your work this week, and in the weeks that follow, will be gathered (along with that of your peers) into a master document you will receive a few days after the end of the course. The document will provide everyone with a variety of ideas for how we can all live more sustainably in our homes and communities.

To complete this assignment,

  • You will first need to select a term from the list of choices in the Week 3 - Term Selection Forum. Reply to the forum with the term that you would like to research. Do not select a term that a classmate has already chosen. No two students will be researching the same topic.
  • Next, download the Week 3 Assignment Template and replace the guiding text with your own words based upon your online research. Please do not include a cover page. All references, however, should be cited in your work and listed at the end, following APA format expectations.

In the template, you will

  • Define the term thoroughly.
  • Clearly relate the term to the week’s theme.
  • Explain how the term affects living things and the physical world.
  • Relate the term to the challenge of achieving environmental sustainability.
  • Justify if the term represents an obstacle to that goal, or perhaps a technique or technology that might promote it.
  • Suggest two specific actions we can take to promote sustainability in relationship to this term.
  • Provide detailed examples to support your ideas.

The Week 3 assignment

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Water 5 V. Muthuraman/SuperStock Learning Objectives After studying this chapter, you should be able to: • • • • • ben85927_05_c05.indd 185 Explain how the hydrological or water cycle works and describe how water is distributed among different spheres of the planet—oceans, glaciers, ice and snow, groundwater, rivers, streams, lakes, wetlands, and water vapor in the atmosphere. Describe the major categories of freshwater use by humans, both extractive and non-extractive, and how overuse and misuse of water resources in some regions is threatening the future sustainability of water supplies. Describe how diversion of water for human uses, destruction of wetland habitats, and pollution of natural waterways is already causing severe water shortages in places like China, the Aral Sea Basin, central Africa, and Mexico. Understand the basic difference between supply-side or hard-path solutions that seek to develop new supplies of water and demand-side or soft-path solutions that emphasize water conservation and greater efficiency in use. Explain the causes for the decline of the Jordan River and how political conflict between nations can be a complicating factor in efforts to protect water supplies and restore endangered ecosystems. 1/27/14 9:09 AM Introduction Pre-Test 1. A scientist who studies the movement, storage, and distribution of water is called a hydrolysist. a. True b. False 2. Which of the following is NOT a major category of human water use? a. Industry b. Agriculture c. Transportation d. Residential 3. During the 20th century, the world population tripled, while water use per person increased by six times. a. True b. False 4. The “supply-side” approach to water conservation emphasizes water-saving techniques and reducing demand. a. True b. False 5. The Friends of the Earth Middle East plan for restoring the Jordan River represents a “hard-path” approach to water management. a. True b. False Answers 1. 2. 3. 4. 5. b. False. The answer can be found in Section 5.1. c. Transportation. The answer can be found in Section 5.2. a. True. The answer can be found in Section 5.3. b. False. The answer can be found in Section 5.4. b. False. The answer can be found in Section 5.5. Introduction When viewed from space, Earth is a watery planet. Indeed, oceans comprise about 71 percent of our planet’s surface, while glistening glaciers cover 10 percent of the continents. Yet water shortages are a serious problem. This contradiction is due, in part, to the fact that the abundance of ocean water is too salty for human use, and much of the remaining freshwater is polluted, used up, or distributed unequally. As summed up by one prominent ecologist, “The wet places in the world don’t need the runoff because they are wet. The dry places of the world need the runoff to irrigate the land, but they don’t get much” (Pimm, 2001). Globally, humans extract about one-sixth of the total volume of all the rivers in the world. But the amount of consumption varies from place to place. In British Columbia, for example, winter snowfall and summer rain are abundant and the population density is low. Thus, rivers carry copious amounts of water into the oceans. On the other hand, in the southwest desert of ben85927_05_c05.indd 186 1/27/14 9:09 AM Water Supply and the Hydrological Cycle SECTION 5.1 the United States, precipitation is low and the population is much larger, so the consumption of freshwater outpaces its replenishment. As a result, the Colorado River, which meanders through the American southwest and into Mexico, no longer reaches the ocean. Instead, much of the water from the once free-flowing Colorado River is diverted and extracted to irrigate the parched landscape. And whereas in the past water from the Colorado River used to reach communities in Mexico, today those areas only receive a trickle of salty river water. Massive diversion and use of water from the Colorado River on the American side of the U.S.Mexico border is a source of tension between the two countries. And while this tension is serious enough, it involves two relatively friendly allies and trading partners. The situation is significantly different in more volatile regions of the world such as the Middle East where conflicts over water are potentially explosive. The Jordan River, for example, is a source of water for Jordan, Syria, Israel, and the Palestinian territories. Water is a critically scarce resource in this region and population growth, climate change, and water pollution and misuse are making it even scarcer. As a result, water issues have and will continue to feature as a key factor in regional political negotiations and disputes. Given its importance, it is remarkable how poorly managed water is as a resource. We regularly use rivers, lakes, and the oceans as a dumping ground for our wastes and allow surface contaminants such as spilled oil and agricultural chemicals to pollute critical groundwater supplies. Water is diverted and pumped hundreds of miles (requiring significant levels of energy use) to irrigate golf courses and suburban lawns in the middle of deserts. And, as we’ll see in the next chapter, massive quantities of water are necessary to extract energy from unconventional oil and gas deposits. Where our water comes from, how we use (and abuse) this critical resource, and what we can do to better conserve and protect it is the focus of this chapter. We already know that a growing human population and the demands of feeding the world are putting increased pressure on water resources. We’ll see in Chapter 7 that climate change could also worsen already-critical water supply conditions in some regions. As a result, everything we can do now to minimize water contamination, pollution, and overuse is essential. The Working Toward Solutions section at the end of this chapter thus provides a wealth of advice and information on how we can do just that. 5.1 Water Supply and the Hydrological Cycle The hydrological or water cycle describes the movement and storage of water between different spheres on the planet. At any point in time water may be stored in the oceans, glaciers, and ice and snow; as groundwater; in rivers, streams, lakes, ponds, and wetlands; and lastly, as water vapor in the atmosphere. Water is constantly moving between these spheres through the processes of evaporation, precipitation, infiltration, melting, and groundwater flow. Only 3 percent of the Earth’s water is freshwater (not salty), and close to 70 percent of that freshwater is frozen in ice caps at the poles and in glaciers. Therefore, we are ultimately dependent for our survival on a small but critical portion of the overall planetary water cycle. In the first part of this Ecological Society of America (ESA) report written by ecologist Robert B. Jackson and co-authors, we see just how massive and important the water cycle actually is. ben85927_05_c05.indd 187 1/27/14 9:09 AM Water Supply and the Hydrological Cycle SECTION 5.1 Beyond our obvious uses of freshwater for drinking, bathing, and washing, our society makes use of water for many other purposes. Scientists break these uses down into categories known as consumptive and instream. Consumptive (or extractive) uses involve removing water from its source for drinking or other residential purposes as well as for industrial use and irrigation of crops. Instream (or non-extractive) uses involve deriving benefits from water without removing it from where it is located. Examples of instream uses include transportation/navigation, recreation, habitat for fish and other aquatic life, hydroelectric power generation, and waste processing. The sustainable management of water supplies frequently involves tradeoffs and/ or conflicts between consumptive and instream uses. This was dramatically illustrated in recent years in the Pacific Northwest when irrigation water from rivers was denied to farmers in order to maintain water levels needed for salmon populations. In addition to surface water management there are also concerns over how groundwater resources are managed. Hydrologists (scientists who study the movement and distribution of water) make a distinction between renewable and nonrenewable groundwater. Over threefourths of all underground water is considered nonrenewable since it is found in aquifers that formed tens of thousands of years ago. Since these aquifers are not replenished by rainfall on the surface, over-extraction of water from them is not sustainable. A primary example of nonrenewable groundwater or a “fossil water” source is the Ogallala Aquifer in the central United States where rapid pumping of water to irrigate Midwestern farmland has lowered the level of the aquifer significantly. In contrast, renewable groundwater refers to aquifers that are regularly replenished by rainfall or snowmelt. Even though groundwater resources are renewable, they can be seriously mismanaged. Examples include when water is removed faster than it is replenished and when pollutants or waste products from the surface are allowed to seep into it. Renewable groundwater deposits can be thought of as bank accounts. As long as we do not withdraw more than is going in, we can maintain a positive balance. Nonrenewable groundwater is better thought of as a one-time inheritance or windfall that we can make use of but only at the expense of lower future balances. A better understanding of the water cycle gained in this section sets the stage for a discussion of water use and misuse in subsequent sections of the chapter. It also will help you understand why water pollution is such a critical environmental issue and why efforts to promote water conservation are so important. By R.B. Jackson, et al. Life on earth depends on the continuous flow of materials through the air, water, soil, and food webs of the biosphere. The movement of water through the hydrological cycle comprises the largest of these flows, delivering an estimated 110,000 cubic kilometers (km3) of water to the land each year as snow and rainfall [a cubic kilometer is an area 1,000 meters wide by 1,000 meters deep by 1,000 meters high, or roughly 10 football fields across, deep, and tall]. Solar energy drives the hydrological cycle, vaporizing water from the surface of oceans, lakes, and rivers as well as from soils and plants (evapotranspiration). Water vapor rises into the atmosphere where it cools, condenses, and eventually rains down anew. This renewable freshwater supply sustains life on the land, in estuaries, and in the freshwater ecosystems of the Earth. ben85927_05_c05.indd 188 1/27/14 9:09 AM SECTION 5.1 Water Supply and the Hydrological Cycle Figure 5.1: Hydrological cycle The hydrological, or water, cycle collects and distributes Earth’s fixed supply of water through the processes of evaporation, evapotranspiration, and precipitation. Water storage in the atmosphere Condensation Water storage in ice and snow Evaporation Precipitation Evapotranspiration Snowmelt runoff to streams Surface runoff Water storage in oceans Stream flow Plant uptake Evaporation Freshwater storage Spring Infiltration Groundwater discharge Groundwater storage Based on information from U.S.G.S. Retrieved from Renewable fresh water provides many services essential to human health and well being, including water for drinking, industrial production, and irrigation, and the production of fish, waterfowl, and shellfish. Fresh water also provides many benefits while it remains in its channels (nonextractive or instream benefits), including flood control, transportation, recreation, waste processing, hydroelectric power, and habitat for aquatic plants and animals. Some benefits, such as irrigation and hydroelectric power, can be Consider This achieved only by damming, diverting, or What is the difference between extractive creating other major changes to natural and non-extractive or instream uses of water flows. Such changes often diminish freshwater? How might these different uses or preclude other instream benefits of come into conflict with one another? fresh water, such as providing habitat for aquatic life or maintaining suitable water quality for human use. ben85927_05_c05.indd 189 1/27/14 9:09 AM Water Supply and the Hydrological Cycle SECTION 5.1 The ecological, social, and economic benefits that freshwater systems provide, and the tradeoffs between consumptive and instream values, will change dramatically in the coming century. Already, over the past one hundred years, both the amount of water humans withdraw worldwide and the land area under irrigation have risen exponentially. Despite this greatly increased consumption, the basic water needs of many people in the world are not being met. Currently, 1.1 billion people lack access to safe drinking water, and 2.8 billion lack basic sanitation services. These deprivations cause approximately 250 million cases of water-related diseases and five to ten million deaths each year. Also, current unmet needs limit our ability to adapt to future changes in water supplies and distribution. Many current systems designed to provide water in relatively stable climatic conditions may be ill prepared to adapt to future changes in climate, consumption, and population. While a global perspective on water withdrawals is important for ensuring sustainable water use, it is insufficient for regional and local stability. How fresh water is managed in particular basins and in individual watersheds is the key to sustainable water management. The Global Water Cycle Surface Water Most of the earth is covered by water, more than one billion km3 of it. The vast majority of that water, however, is in forms unavailable to land-based or freshwater ecosystems. Less than 3 percent is fresh enough to drink or to irrigate crops, and of that total, more than two-thirds is locked in glaciers and ice caps. Freshwater lakes and rivers hold 100,000 km3 globally, less than one ten-thousandth of all water on earth. Water vapor in the atmosphere exerts an important influence on climate and on the water cycle, even though only 15,000 km3 of water is typically held in the atmosphere at any time. This tiny fraction, however, is vital for the biosphere. Water vapor is the most important of the so-called greenhouse gases (others include carbon dioxide, nitrous oxide, and methane) that warm the earth by trapping heat in the atmosphere. Water vapor contributes approximately two-thirds of the total warming that greenhouse gases supply. Without these gases, the mean surface temperature of the earth would be well below freezing, and liquid water would be absent over much of the planet. Equally important for life, atmospheric water turns over every ten days or so as water vapor condenses and rains to earth and the heat of the sun evaporates new supplies of vapor from the liquid reservoirs on earth. ben85927_05_c05.indd 190 1/27/14 9:09 AM SECTION 5.1 Water Supply and the Hydrological Cycle Figure 5.2: Earth’s water distribution Although Earth is considered a “watery planet,” only about 3 percent of Earth’s water is fresh, and much of that is locked up in ice caps and glaciers. Since life on Earth depends on this limited supply of water, it is critical to learn to use it in a sustainable manner. Fresh water 3% Ice caps and glaciers 68.7% Ground water Earth’s water 30.1% Other .09% Saline (oceans) 97% Rivers 2% Fresh surface water (liquid) Swamps 11% Lakes 87% Based on information from U.S.G.S. Retrieved from Solar energy typically evaporates about 425,000 km3 of ocean water each year. Most of this water rains back directly to the oceans, but approximately 10 percent falls on land. If this were the only source of rainfall, average precipitation across the earth’s land surfaces would be only 25 centimeters (cm) a year, a value typical for deserts or semi-arid regions. Instead, a second, larger source of water is recycled from plants and the soil through evapotranspiration. The water vapor from this source creates a direct feedback between the land surface and regional climate. The cycling of other materials such as carbon and nitrogen (biogeochemical cycling) is strongly coupled to this water flux through the patterns of plant growth and microbial decomposition, and this coupling creates additional feedbacks between vegetation and climate. This second source of recycled water contributes two-thirds of the 70 cm of precipitation that falls over land each year. Taken together, these two sources account for the 110,000 km3 of renewable freshwater available each year for terrestrial, freshwater, and estuarine ecosystems. ben85927_05_c05.indd 191 1/27/14 9:09 AM Water Supply and the Hydrological Cycle SECTION 5.1 Because the amount of rain that falls on land is greater than the amount of water that evaporates from it, the extra 40,000 km3 of water returns to the oceans, primarily via rivers and underground aquifers. A number of factors affect how much of this water is available for human use on its journey to the oceans. These factors include whether the precipitation falls as rain or snow, the timing of precipitation relative to patterns of seasonal temperature and sunlight, and the regional topography. For example, in many mountain regions, most precipitation falls as snow during winter, and spring snowmelt causes peak flows that flood major river systems. In some tropical regions, monsoons rather than snowmelt create seasonal flooding. In other regions, excess precipitation percolates into the soil to recharge ground water or is stored in wetlands. Widespread loss of wetlands and floodplains, however, reduces their ability to absorb these high flows and speeds the runoff of excess nutrients and contaminants to estuaries and other coastal environments. More than half of all wetlands in the U. S. have already been drained, dredged, filled, or planted. Available water is not evenly distributed globally. Two thirds of all precipitation falls in the tropics (between 30 degrees N and 30 degree S latitude) due to greater solar radiation and evaporation there. Daily evaporation from the oceans ranges from 0.4 cm at the equator to less than 0.1 cm at the poles. Typically, tropical regions also have larger runoff. Roughly half of the precipitation that falls in rainforests becomes runoff, while in the deserts low rainfall and high evaporation rates combine to greatly reduce runoff. The Amazon, for example, carries 15 percent of all water returning to the global oceans. In contrast, the Colorado River drainage, which is one-tenth the size of the Amazon, has a historic annual runoff 300 times smaller. Similar variation occurs at continental scales. Average runoff in Australia is only 4 cm per year, eight times less than in North America and orders of magnitude less than in tropical South America. As a result of these and many other disparities, freshwater availability varies dramatically worldwide. Ground Water Approximately 99 percent of all liquid fresh water is in underground aquifers, and at least a quarter of the world’s population draws its water from these groundwater supplies. Estimates of the global water cycle generally treat rates of groundwater inflow and outflow as if they were balanced. In reality, however, this resource is being depleted globally. Ground water typically turns over more slowly than most other water pools, often in hundreds to tens of thousands of years, although the range in turnover rates is large. Indeed, a majority of ground water is not actively turning over or being recharged from the earth’s surface at all. Instead, it is “fossil water,” a relic of wetter ancient climatic conditions and melting Pleistocene ice sheets that accumulated over tens of th ...
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Week 3Assignment Template
Sustainable Living Guide Contributions, Part Three of Four:
Sustaining Our Water Resources
Your Term: Hydrological cycle
The term chosen from week three is a hydrological cycle which refers o the endless
circulation of water from the bodies of water to the atmosphere and back to the ground in form of
rain, then to the bodies of water via surface runoff. It is through evaporation and transpiration
from trees that water vapor moves to the atmosphere. Once the water vapor is in the atmosphere,
it is subjected to lower temperatures which lead to condensation. On further condensatio...

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