A building’s location and surroundings play a key role in regulating its temperature and illumination. For example, trees, landscaping, and hills can provide shade and block wind. In cooler climates, designing buildings with an east-west orientation to increase the number of south-facing windows minimizes energy use, by maximizing passive solar heating. Tight building design, including energy-efficient windows, well-sealed doors, and additional thermal insulation of walls, basement slabs, and foundations can reduce heat loss by 25 to 50%.

Modern building practices often demonstrate little regard for energy efficiency or the larger economic, environmental or social impacts of the built environment. Green building attempts to break with these practices. Early efforts to bring change to the building sector in the 1960s through the 1980s generally focused on single issues such as energy efficiency and conservation of natural resources. Green building now integrates a wide range of building design, construction, and operation and maintenance practices to provide healthier living and working environments and minimize environmental impacts. Crucial to the success of green building has been the application of integrated design principles, a whole-building-systems approach, which brings together the key stakeholders and design professionals as a core team to work collaboratively from the early planning stages through to the building’s occupation.

Table Of Contents :

Executive Summary 5

What is Energy Efficiency? 7
Overview 7
Energy Efficient Appliances 9
Energy Efficient Industries 9
Energy Efficient Vehicles 10
Energy Efficiency and Sustainable Energy 11
Rebound Effect and Energy Efficiency 13

Introduction to Energy Efficient Buildings 14
Overview 14
Features of a Green Building 15
How widespread is the Concept of Green Buildings 16
Negative Environmental Impacts of Current Building Practices 17
Benefits of Green Building 19
Some Green Building Rating Systems 21
GHG Emissions and Green Buildings 22
AIA 2030 Challenge 23

Elements of an Energy Efficient Building 24
Overview 24
Basic Principles of an Energy Efficient Building 24
Market Developments 26
Looking at the Thermal Envelope 27
Wall and Roof Assemblies 27
Insulation 28
Windows 30
Weatherstripping and Caulking 31
Controlled Ventilation 33
Heating and Cooling Systems 34
Looking at Energy-Efficient Appliances 35
Advantages and Disadvantages of Energy Efficient Buildings 37
Building and Buying an Energy Efficient Home 38
Energy Flows in a Building 40
Standards of Eco Living 42
Passive House Concept 42
Minergie House Concept 42
Zero Energy House Concept 43
Energy Plus House Concept 43
Design Components 44

Financial Considerations of EEBs 46
Overview 46
Significance of Energy Cost 47
Cost of Achieving Energy Efficiency 48
Major Trends 51
Patterns in Building Stock 51
Consumer and Demographic Trends 52
Trends in Energy Demand in the built Environment and Supply 52
Government Trends 53
Scarcity of Resources 54
Industrial/Commercial Trends 54
Forces Driving EEBs 56
Market Forces 56
Government Regulations and Programs 57
Challenges to Energy Efficient Buildings 59
Challenges to Economic Pricing of Energy 59
Factors such as Environment, Energy Security, Social Policy and Employment 59
Technical Skills 60
Doubts About Energy Consumption and Conservation 61
Lack of Confidence in New Technologies 61
Lack of Knowledge on Expenditure and Benefit 62
Availability of Capital 62
Separate Capital and Operating Budgets 63
Split Incentives 63
Risks and Uncertainties 65
Lack of Coordination and Consistency in Government Policies 65
Lack of Research Investments 66
Technological Challenges 66
Institutional Challenges 67
Overall Energy Consumption by Buildings 68
Energy Use in Buildings 74
Requirement of a Supportive Regulative Framework 77

Energy Policy Act of 2005 and Energy Efficient Buildings 81
Overview 81
Qualification Factors 81
Tax Deduction 82
Certification Requirements 82
Calculating of Design Methods and Technologies 82
Determining Building Compliance 83

Interim Rules for Lighting Projects 84
Overview of the Program 85
Opportunities for Energy and Cost Savings 85
Zero Energy Goals 86
Tax Incentives for Energy Efficiency 87
Tax Incentives for Commercial Buildings 88
Tax Incentives for Residential Buildings 89
Buildings Efficiency and Economic Recovery 89

Building America Program 91
Overview of the Program 91
Systems Engineering Approach 92
Methodology 94
Results 95
Benefits for the Buyer & Homeowners 95
Benefits for Buyers 95
Benefits for the Homeowners 96
Benefits for the Country 97
Energy Star� Program 98
Obama�s New Energy Efficiency Efforts 100
Energy Efficient Buildings in Europe 104
Energy in the EU 104
Energy Efficiency in Buildings in Europe 107

Energy Efficiency in EU 107
Overview 107
Policy Developments 108
Regulations in Relation to Buildings 110
Energy Performance of Buildings 110
Directive on the Energy Performance of Buildings 112
Directive 2004/8/EC on the Promotion of Cogeneration 117
Program for EU Member States related to Buildings 118
Energy Services to Buildings 118
Development of the EU Framework 120
Improving Energy Efficiency of Buildings in EU Member States 121
Energy Efficiency Regulations 122
Existing National Programs 122
Directive on Energy Performance of Buildings 126

Major Players 127
Governments 128
The European Union 129
International Energy Agency 130
European Energy Charter 131
European Committee for Standardization 131
Energie-Cits 131
European Network of Buildings Research Institutes 132
European Investment Bank 133
European Bank for Reconstruction and Development 133
Future 134

Country Analysis 136
China 136
Hong Kong 138
India 140
Japan 141
Malaysia 143
Philippines 145
Singapore 146
South Korea 147
Taiwan 149
Thailand 151
Case Studies 154
Masdar City, Dubai 154

Energy-Efficient Building Designing of the Louisiana Capitol Complex 157
Energy Efficient Building Programs in Hawaii 159
Enermodal Engineering�s Building 161

Major Players 164
Actelios 164
Cemex 165
DuPont 166
EDF 167
Enermodal Engineering 168
Honeywell 169
Lafarge 170
Philips 171
TEPCO 172

Appendix 174

Glossary 179

About the Publisher 192

List of Figures and Tables
Tables
Figure 1: Possible Areas of Air Leakage 32
Figure 2: Heat Recovery Ventilation 34
Figure 3: Energy Flows within a Building 41
Figure 4: Design Impacts on Energy Use 45
Figure 5: Energy and Total Costs by Quality of Fittings 48
Figure 6: Costing Green: A Comprehensive Cost Database and Budgeting Methodology 49
Figure 7: Best and Worst Case Projections of Site Energy Demand 69
Figure 8: Existing Building Floor Space 70
Figure 9: Building Energy Projection by Region 71
Figure 10: Site Energy Sources 72
Figure 11: Primary Energy 72
Figure 12: Life Cycle Energy Use 73
Figure 13: Complex Value Chain 75
Figure 14: Three Approaches in a Supportive Framework 78
Figure 15: Sources of Environmental Impacts in Each Phase of the Building Life Cycle 79
Figure 16: Energy Demand in the EU 105
Figure 17: Compliance Framework for Hong Kong Building Energy Standards 139
Figure 18: Distribution of Energy Demand of Various Buildings Components 174
Figure 19: Most Cost-effective Method for Lowering GHG Emissions 175
Figure 20: Building Energy End Use Consumption 176
Figure 21:Integrated Building Systems: Active Shading + Dimmable Lighting = Load Management Strategy 178

Tables

Table 1: Potential National Lighting Savings 177

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(986, ‘Since 2006 the state began pushing Energy Emissions around the Solar Energy Industry support to increase Shenzhen Yantai Guangzhou and other cities as well as in Jiangsu Hainan Province has announced the implementation of mandatory installation of solar water heaters policy solar energy and building integrated as Building energy efficiency Find a way out solar energy quot put a order quot contributed However the promotion of solar energy and construction integration is more difficult there are multiple reasons for this embarrassing situation br br Solar water heater can not meet current building requirements for diversification marketing models revealed many shortcomings First the owners to install solar cluttered affecting new residential landscape to create visual pollution in urban marginal landscape Second imperfect as domestic standards different standards for solar destruction of the building structure and function in the construction of the water lightning wind bearing a security risk areas solar injury solar and other events often found in the newspapers fall height Third many of the top floor of the roof has become the owner of the quot private domain quot because many property owners to install solar roof which disputes can easily cause the late property management for the inconvenience Fourth as the country quot with saving energy and building quot initiative the launching of the urbanization process now more and more high rise buildings with limited roof space it increasingly difficult to meet the majority of owners on the use of solar energy needs Solar water heaters deficiencies but also made a lot of real estate agency love hate and many communities the property is strictly prohibited to install solar energy many cities such as Dalian also issued a quot no security order quot br br Due to information asymmetry some developers do not understand the solar product design institutes so that they can not accept the product or not well integrated to the building which will be solar Solar industry some companies lack of self binding which do not meet the standards of building integrated products installed in buildings not only did not play the role of energy conservation but also affected the building aesthetics resulting in solar energy consumers developers understanding of solar energy products deviation br br The experts pointed out that the biggest bottleneck is the promotion of countries also lack of effective monitoring throughout the solar energy products and standard system can be divided into the integration of solar energy and building standards and product standards of two categories br br Principle if the solar system the introduction of construction it must have a certain standard so that all the designers all of the real estate developer and all of the construction industry are available through a standardized system in the early building integration can be carried out to consider as every household security windows high rise elevator installation is as simple as naturally br br Force Norit technical experts Qi kun said the companies are accelerating the pace of energy conservation in such circumstances can not first go after other standards promulgated the implementation of solar energy and construction integration the best way is to continued in the implementation of these norms the establishment of demonstration Project To work to promote standards in the model of perfect in turn regulate construction so as to promote the integration of solar energy and building positive development Norit force in the country to implement more than 1 000 solar energy and building integrated Chemical industry Process can ensure that each project are demonstration projects some of them works also highly positive Hangzhou Long Island greenway as water engineering were among the United Nations quot Habitat Award quot Shanghai Construction ASTRI projects to receive the National Green Building Innovation Award first prize for building an integrated class project Ningbo quot Vico Waterfront mind quot Solar Project become the quot Ministry of residential energy conservation demonstration area quot and so on br br Promotion practice in engineering based on force Norit first introduced in the country quot Solar Hot water system Integrated Design and Application Architecture quot standard atlas for the synchronization design of solar energy and architecture synchronous construction synchronization testing synchronization management of technical standards became the first most comprehensive and most representative building integrated solar energy and Atlas Power Norit this approach is the best model among the perfect example of specification br br Product or brand from the point of view what kind of solar energy to meet the standards can and building quot good match quot mean Deputy General Manager of Literature and Philosophy force Norit Liang said that the country should first of all related departments and developers jointly develop solar energy enterprises or building integrated solar energy products for the standard first rigid standards for products to be laid down to ensure the installation in building on the quality of solar energy Second for the solar industry the Government should create a fair and equitable bidding environment and the tender quot market quot so not only can guarantee the quality of solar energy and building integrated but also to promote the sound development of the solar energy industry br br Review the history of solar energy every step of the development depended on government support Liang Wen Zhe said future development in the solar industry the government functions from the command to boot through macro control the solar industry continues to market and going out in the laws of the market screening continuous improvement to building integration specification the final specification to enhance the solar energy industry solar industry to achieve the big step The enterprises should also upgrade their products to enable them to better integrate with the architecture to realize parts of solar water heaters Solar industry to shoulder the important task of energy conservation which requires all enterprises to improve self binding responsible for the product the consumer is responsible to the State so that their products comply with or better than national standards to parts of the solar solar energy and building the foundation for perfect integration ‘)

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I INTRODUCTION

Earth (planet), one of nine planets in the solar system, the only planet known to harbor life, and the “home” of human beings. From space Earth resembles a big blue marble with swirling white clouds floating above blue oceans. About 71 percent of Earth’s surface is covered by water, which is essential to life. The rest is land, mostly in the form of continents that rise above the oceans.

Earth An oxygen-rich and protective atmosphere, moderate temperatures, abundant water, and a varied chemical composition enable Earth to support life, the only planet known to harbor life. The planet is composed of rock and metal, which are present in molten form beneath its surface. The Apollo 17 spacecraft took this snapshot in 1972 of the Arabian Peninsula, the African continent, and Antarctica (most of the white area near the bottom).

 Earth’s surface is surrounded by a layer of gases known as the atmosphere, which extends upward from the surface, slowly thinning out into space. Below the surface is a hot interior of rocky material and two core layers composed of the metals nickel and iron in solid and liquid form.

Unlike the other planets, Earth has a unique set of characteristics ideally suited to supporting life as we know it. It is neither too hot, like Mercury, the closest planet to the Sun, nor too cold, like distant Mars and the even more distant outer planets—Jupiter, Saturn, Uranus, Neptune, and tiny Pluto. Earth’s atmosphere includes just the right amount of gases that trap heat from the Sun, resulting in a moderate climate suitable for water to exist in liquid form. The atmosphere also helps block radiation from the Sun that would be harmful to life. Earth’s atmosphere distinguishes it from the planet Venus, which is otherwise much like Earth. Venus is about the same size and mass as Earth and is also neither too near nor too far from the Sun. But because Venus has too much heat-trapping carbon dioxide in its atmosphere, its surface is extremely hot—462°C (864°F)—hot enough to melt lead and too hot for life to exist.

Although Earth is the only planet known to have life, scientists do not rule out the possibility that life may once have existed on other planets or their moons, or may exist today in primitive form. Mars, for example, has many features that resemble river channels, indicating that liquid water once flowed on its surface. If so, life may also have evolved there, and evidence for it may one day be found in fossil form. Water still exists on Mars, but it is frozen in polar ice caps, in permafrost, and possibly in rocks below the surface.

For thousands of years, human beings could only wonder about Earth and the other observable planets in the solar system. Many early ideas—for example, that the Earth was a sphere and that it traveled around the Sun—were based on brilliant reasoning. However, it was only with the development of the scientific method and scientific instruments, especially in the 18th and 19th centuries, that humans began to gather data that could be used to verify theories about Earth and the rest of the solar system. By studying fossils found in rock layers, for example, scientists realized that the Earth was much older than previously believed. And with the use of telescopes, new planets such as Uranus, Neptune, and Pluto were discovered.

Earth from the Moon In the late 1960s, people saw for the first time what Earth looked like from space. This famous photo of Earth was taken by astronauts on the Apollo 8 mission as they orbited the Moon in 1968.

In the second half of the 20th century, more advances in the study of Earth and the solar system occurred due to the development of rockets that could send spacecraft beyond Earth. Human beings were able to study and observe Earth from space with satellites equipped with scientific instruments. Astronauts landed on the Moon and gathered ancient rocks that revealed much about the early solar system. During this remarkable advancement in human history, humans also sent unmanned spacecraft to the other planets and their moons. Spacecraft have now visited all of the planets except Pluto. The study of other planets and moons has provided new insights about Earth, just as the study of the Sun and other stars like it has helped shape new theories about how Earth and the rest of the solar system formed.

As a result of this recent space exploration, we now know that Earth is one of the most geologically active of all the planets and moons in the solar system. Earth is constantly changing. Over long periods of time land is built up and worn away, oceans are formed and re-formed, and continents move around, break up, and merge.

Life itself contributes to changes on Earth, especially in the way living things can alter Earth’s atmosphere. For example, Earth at one time had the same amount of carbon dioxide in its atmosphere as Venus now has, but early forms of life helped remove this carbon dioxide over millions of years. These life forms also added oxygen to Earth’s atmosphere and made it possible for animal life to evolve on land.

A variety of scientific fields have broadened our knowledge about Earth, including biogeography, climatology, geology, geophysics, hydrology, meteorology, oceanography, and zoogeography. Collectively, these fields are known as Earth science. By studying Earth’s atmosphere, its surface, and its interior and by studying the Sun and the rest of the solar system, scientists have learned much about how Earth came into existence, how it changed, and why it continues to change.

II EARTH, THE SOLAR SYSTEM, AND THE GALAXY

Earth is the third planet from the Sun, after Mercury and Venus. The average distance between Earth and the Sun is 150 million km (93 million mi). Earth and all the other planets in the solar system revolve, or orbit, around the Sun due to the force of gravitation. The Earth travels at a velocity of about 107,000 km/h (about 67,000 mph) as it orbits the Sun. All but one of the planets orbit the Sun in the same plane—that is, if an imaginary line were extended from the center of the Sun to the outer regions of the solar system, the orbital paths of the planets would intersect that line. The exception is Pluto, which has an eccentric (unusual) orbit.

Earth’s orbital path is not quite a perfect circle but instead is slightly elliptical (oval-shaped). For example, at maximum distance Earth is about 152 million km (about 95 million mi) from the Sun; at minimum distance Earth is about 147 million km (about 91 million mi) from the Sun. If Earth orbited the Sun in a perfect circle, it would always be the same distance from the Sun.

The solar system, in turn, is part of the Milky Way Galaxy, a collection of billions of stars bound together by gravity. The Milky Way has armlike discs of stars that spiral out from its center. The solar system is located in one of these spiral arms, known as the Orion arm, which is about two-thirds of the way from the center of the Galaxy. In most parts of the Northern Hemisphere, this disc of stars is visible on a summer night as a dense band of light known as the Milky Way.

Milky Way Galaxy Our own solar system exists within one of the spiral arms of the disk-shaped galaxy called the Milky Way. This false-color image looks toward the center of the Milky Way, located 30,000 light-years away. Bright star clusters are visible along with darker areas of dust and gas.Photo Researchers, Inc./Morton-Milon/Science Source

Earth is the fifth largest planet in the solar system. Its diameter, measured around the equator, is 12,756 km (7,926 mi). Earth is not a perfect sphere but is slightly flattened at the poles. Its polar diameter, measured from the North Pole to the South Pole, is somewhat less than the equatorial diameter because of this flattening. Although Earth is the largest of the four planets—Mercury, Venus, Earth, and Mars—that make up the inner solar system (the planets closest to the Sun), it is small compared with the giant planets of the outer solar system—Jupiter, Saturn, Uranus, and Neptune. For example, the largest planet, Jupiter, has a diameter at its equator of 143,000 km (89,000 mi), 11 times greater than that of Earth. A famous atmospheric feature on Jupiter, the Great Red Spot, is so large that three Earths would fit inside it.

Earth has one natural satellite, the Moon. The Moon orbits the Earth, completing one revolution in an elliptical path in 27 days 7 hr 43 min 11.5 sec. The Moon orbits the Earth because of the force of Earth’s gravity. However, the Moon also exerts a gravitational force on the Earth. Evidence for the Moon’s gravitational influence can be seen in the ocean tides. A popular theory suggests that the Moon split off from Earth more than 4 billion years ago when a large meteorite or small planet struck the Earth.

As Earth revolves around the Sun, it rotates, or spins, on its axis, an imaginary line that runs between the North and South poles. The period of one complete rotation is defined as a day and takes 23 hr 56 min 4.1 sec. The period of one revolution around the Sun is defined as a year, or 365.2422 solar days, or 365 days 5 hr 48 min 46 sec. Earth also moves along with the Milky Way Galaxy as the Galaxy rotates and moves through space. It takes more than 200 million years for the stars in the Milky Way to complete one revolution around the Galaxy’s center.

Earth’s axis of rotation is inclined (tilted) 23.5° relative to its plane of revolution around the Sun. This inclination of the axis creates the seasons and causes the height of the Sun in the sky at noon to increase and decrease as the seasons change. The Northern Hemisphere receives the most energy from the Sun when it is tilted toward the Sun. This orientation corresponds to summer in the Northern Hemisphere and winter in the Southern Hemisphere. The Southern Hemisphere receives maximum energy when it is tilted toward the Sun, corresponding to summer in the Southern Hemisphere and winter in the Northern Hemisphere. Fall and spring occur in between these orientations.

III EARTH’S ATMOSPHERE

The atmosphere is a layer of different gases that extends from Earth’s surface to the exosphere, the outer limit of the atmosphere, about 9,600 km (6,000 mi) above the surface. Near Earth’s surface, the atmosphere consists almost entirely of nitrogen (78 percent) and oxygen (21 percent). The remaining 1 percent of atmospheric gases consists of argon (0.9 percent); carbon dioxide (0.03 percent); varying amounts of water vapor; and trace amounts of hydrogen, nitrous oxide, ozone, methane, carbon monoxide, helium, neon, krypton, and xenon.

A Layers of the Atmosphere

Divisions of the Atmosphere Without our atmosphere, there would be no life on Earth. A relatively thin envelope, the atmosphere consists of layers of gases that support life and provide protection from harmful radiation.© Microsoft Corporation. All Rights Reserved.

The layers of the atmosphere are the troposphere, the stratosphere, the mesosphere, the thermosphere, and the exosphere. The troposphere is the layer in which weather occurs and extends from the surface to about 16 km (about 10 mi) above sea level at the equator. Above the troposphere is the stratosphere, which has an upper boundary of about 50 km (about 30 mi) above sea level. The layer from 50 to 90 km (30 to 60 mi) is called the mesosphere. At an altitude of about 90 km, temperatures begin to rise. The layer that begins at this altitude is called the thermosphere because of the high temperatures that can be reached in this layer (about 1200°C, or about 2200°F). The region beyond the thermosphere is called the exosphere. The thermosphere and the exosphere overlap with another region of the atmosphere known as the ionosphere, a layer or layers of ionized air extending from almost 60 km (about 50 mi) above Earth’s surface to altitudes of 1,000 km (600 mi) and more.

Earth’s atmosphere and the way it interacts with the oceans and radiation from the Sun are responsible for the planet’s climate and weather. The atmosphere plays a key role in supporting life. Almost all life on Earth uses atmospheric oxygen for energy in a process known as cellular respiration, which is essential to life. The atmosphere also helps moderate Earth’s climate by trapping radiation from the Sun that is reflected from Earth’s surface. Water vapor, carbon dioxide, methane, and nitrous oxide in the atmosphere act as “greenhouse gases.” Like the glass in a greenhouse, they trap infrared, or heat, radiation from the Sun in the lower atmosphere and thereby help warm Earth’s surface. Without this greenhouse effect, heat radiation would escape into space, and Earth would be too cold to support most forms of life.

Other gases in the atmosphere are also essential to life. The trace amount of ozone found in Earth’s stratosphere blocks harmful ultraviolet radiation from the Sun. Without the ozone layer, life as we know it could not survive on land. Earth’s atmosphere is also an important part of a phenomenon known as the water cycle or the hydrologic cycle. See also Atmosphere.

B The Atmosphere and the Water Cycle

The water cycle simply means that Earth’s water is continually recycled between the oceans, the atmosphere, and the land. All of the water that exists on Earth today has been used and reused for billions of years. Very little water has been created or lost during this period of time. Water is constantly moving on Earth’s surface and changing back and forth between ice, liquid water, and water vapor.

The water cycle begins when the Sun heats the water in the oceans and causes it to evaporate and enter the atmosphere as water vapor. Some of this water vapor falls as precipitation directly back into the oceans, completing a short cycle. Some of the water vapor, however, reaches land, where it may fall as snow or rain. Melted snow or rain enters rivers or lakes on the land. Due to the force of gravity, the water in the rivers eventually empties back into the oceans. Melted snow or rain also may enter the ground. Groundwater may be stored for hundreds or thousands of years, but it will eventually reach the surface as springs or small pools known as seeps. Even snow that forms glacial ice or becomes part of the polar caps and is kept out of the cycle for thousands of years eventually melts or is warmed by the Sun and turned into water vapor, entering the atmosphere and falling again as precipitation. All water that falls on land eventually returns to the ocean, completing the water cycle.

IV EARTH’S SURFACE

Earth’s surface is the outermost layer of the planet. It includes the hydrosphere, the crust, and the biosphere.

A Hydrosphere

The hydrosphere consists of the bodies of water that cover 71 percent of Earth’s surface. The largest of these are the oceans, which contain over 97 percent of all water on Earth. Glaciers and the polar ice caps contain just over 2 percent of Earth’s water in the form of solid ice. Only about 0.6 percent is under the surface as groundwater. Nevertheless, groundwater is 36 times more plentiful than water found in lakes, inland seas, rivers, and in the atmosphere as water vapor. Only 0.017 percent of all the water on Earth is found in lakes and rivers. And a mere 0.001 percent is found in the atmosphere as water vapor. Most of the water in glaciers, lakes, inland seas, rivers, and groundwater is fresh and can be used for drinking and agriculture. Dissolved salts compose about 3.5 percent of the water in the oceans, however, making it unsuitable for drinking or agriculture unless it is treated to remove the salts.

B Crust

The crust consists of the continents, other land areas, and the basins, or floors, of the oceans. The dry land of Earth’s surface is called the continental crust. It is about 15 to 75 km (9 to 47 mi) thick. The oceanic crust is thinner than the continental crust. Its average thickness is 5 to 10 km (3 to 6 mi). The crust has a definite boundary called the Mohorovi

Oceanic crust and continental crust differ in the type of rocks they contain. There are three main types of rocks: igneous, sedimentary, and metamorphic. Igneous rocks form when molten rock, called magma, cools and solidifies. Sedimentary rocks are usually created by the breakdown of igneous rocks. They tend to form in layers as small particles of other rocks or as the mineralized remains of dead animals and plants that have fused together over time. The remains of dead animals and plants occasionally become mineralized in sedimentary rock and are recognizable as fossils. Metamorphic rocks form when sedimentary or igneous rocks are altered by heat and pressure deep underground.

Oceanic crust consists of dark, dense igneous rocks, such as basalt and gabbro. Continental crust consists of lighter-colored, less dense igneous rocks, such as granite and diorite. Continental crust also includes metamorphic rocks and sedimentary rocks.

C Biosphere

The biosphere includes all the areas of Earth capable of supporting life. The biosphere ranges from about 10 km (about 6 mi) into the atmosphere to the deepest ocean floor. For a long time, scientists believed that all life depended on energy from the Sun and consequently could only exist where sunlight penetrated. In the 1970s, however, scientists discovered various forms of life around hydrothermal vents on the floor of the Pacific Ocean where no sunlight penetrated. They learned that primitive bacteria formed the basis of this living community and that the bacteria derived their energy from a process called chemosynthesis that did not depend on sunlight. Some scientists believe that the biosphere may extend relatively deep into Earth’s crust. They have recovered what they believe are primitive bacteria from deeply drilled holes below the surface.

D Changes to Earth’s Surface

Earth’s surface has been constantly changing ever since the planet formed. Most of these changes have been gradual, taking place over millions of years. Nevertheless, these gradual changes have resulted in radical modifications, involving the formation, erosion, and re-formation of mountain ranges, the movement of continents, the creation of huge supercontinents, and the breakup of supercontinents into smaller continents.

The weathering and erosion that result from the water cycle are among the principal factors responsible for changes to Earth’s surface. Another principal factor is the movement of Earth’s continents and seafloors and the buildup of mountain ranges due to a phenomenon known as plate tectonics. Heat is the basis for all of these changes. Heat in Earth’s interior is believed to be responsible for continental movement, mountain building, and the creation of new seafloor in ocean basins. Heat from the Sun is responsible for the evaporation of ocean water and the resulting precipitation that causes weathering and erosion. In effect, heat in Earth’s interior helps build up Earth’s surface while heat from the Sun helps wear down the surface.

D1 Weathering

Weathering is the breakdown of rock at and near the surface of Earth. Most rocks originally formed in a hot, high-pressure environment below the surface where there was little exposure to water. Once the rocks reached Earth’s surface, however, they were subjected to temperature changes and exposed to water. When rocks are subjected to these kinds of surface conditions, the minerals they contain tend to change. These changes constitute the process of weathering. There are two types of weathering: physical weathering and chemical weathering.

Physical weathering involves a decrease in the size of rock material. Freezing and thawing of water in rock cavities, for example, splits rock into small pieces because water expands when it freezes.

Chemical weathering involves a chemical change in the composition of rock. For example, feldspar, a common mineral in granite and other rocks, reacts with water to form clay minerals, resulting in a new substance with totally different properties than the parent feldspar. Chemical weathering is of significance to humans because it creates the clay minerals that are important components of soil, the basis of agriculture. Chemical weathering also causes the release of dissolved forms of sodium, calcium, potassium, magnesium, and other chemical elements into surface water and groundwater. These elements are carried by surface water and groundwater to the sea and are the sources of dissolved salts in the sea.

D2 Erosion

Glacial Erosion Glaciers erode the earth’s surface through processes such as abrasion, crushing, and fracturing of the material in the glacier’s path. Glaciers move by growing or shrinking, depending on the climate. Moving glaciers erode and transport large quantities of rocks, sand, and other particles along their path. The icy path shown here is a moraine formed by a glacier in Switzerland.Photo Researchers, Inc./Paolo Koch

Erosion is the process that removes loose and weathered rock and carries it to a new site. Water, wind, and glacial ice combined with the force of gravity can cause erosion.

Erosion by running water is by far the most common process of erosion. It takes place over a longer period of time than other forms of erosion. When water from rain or melted snow moves downhill, it can carry loose rock or soil with it. Erosion by running water forms the familiar gullies and V-shaped valleys that cut into most landscapes. The force of the running water removes loose particles formed by weathering. In the process, gullies and valleys are lengthened, widened, and deepened. Often, water overflows the banks of the gullies or river channels, resulting in floods. Each new flood carries more material away to increase the size of the valley. Meanwhile, weathering loosens more and more material so the process continues.

Erosion by glacial ice is less common, but it can cause the greatest landscape changes in the shortest amount of time. Glacial ice forms in a region where snow fails to melt in the spring and summer and instead builds up as ice. For major glaciers to form, this lack of snowmelt has to occur for a number of years in areas with high precipitation. As ice accumulates and thickens, it flows as a solid mass. As it flows, it has a tremendous capacity to erode soil and even solid rock. Ice is a major factor in shaping some landscapes, especially mountainous regions. Glacial ice provides much of the spectacular scenery in these regions. Features such as horns (sharp mountain peaks), ar

Wind is an important cause of erosion only in arid (dry) regions. Wind carries sand and dust, which can scour even solid rock.

Many factors determine the rate and kind of erosion that occurs in a given area. The climate of an area determines the distribution, amount, and kind of precipitation that the area receives and thus the type and rate of weathering. An area with an arid climate erodes differently than an area with a humid climate. The elevation of an area also plays a role by determining the potential energy of running water. The higher the elevation the more energetically water will flow due to the force of gravity. The type of bedrock in an area (sandstone, granite, or shale) can determine the shapes of valleys and slopes, and the depth of streams.

A landscape’s geologic age—that is, how long current conditions of weathering and erosion have affected the area—determines its overall appearance. Relatively young landscapes tend to be more rugged and angular in appearance. Older landscapes tend to have more rounded slopes and hills. The oldest landscapes tend to be low-lying with broad, open river valleys and low, rounded hills. The overall effect of the wearing down of an area is to level the land; the tendency is toward the reduction of all land surfaces to sea level.

D3 Plate Tectonics

Opposing this tendency toward leveling is a force responsible for raising mountains and plateaus and for creating new landmasses. These changes to Earth’s surface occur in the outermost solid portion of Earth, known as the lithosphere. The lithosphere consists of the crust and another region known as the upper mantle and is approximately 65 to 100 km (40 to 60 mi) thick. Compared with the interior of the Earth, however, this region is relatively thin. The lithosphere is thinner in proportion to the whole Earth than the skin of an apple is to the whole apple.

Scientists believe that the lithosphere is broken into a series of plates, or segments. According to the theory of plate tectonics, these plates move around on Earth’s surface over long periods of time. Tectonics comes from the Greek word, tektonikos, which means “builder.”

According to the theory, the lithosphere is divided into large and small plates. The largest plates include the Pacific plate, the North American plate, the Eurasian plate, the Antarctic plate, the Indo-Australian plate, and the African plate. Smaller plates include the Cocos plate, the Nazca plate, the Philippine plate, and the Caribbean plate. Plate sizes vary a great deal. The Cocos plate is 2,000 km (1,000 mi) wide, while the Pacific plate is nearly 14,000 km (nearly 9,000 mi) wide.

These plates move in three different ways in relation to each other. They pull apart or move away from each other, they collide or move against each other, or they slide past each other as they move sideways. The movement of these plates helps explain many geological events, such as earthquakes and volcanic eruptions as well as mountain building and the formation of the oceans and continents.

?i? discontinuity, or simply the Moho. The boundary separates the crust from the underlying mantle, which is much thicker and is part of Earth’s interior.êtes (sharp ridges), glacially formed lakes, and U-shaped valleys are all the result of glacial erosion.