Table of Contents
Chapter 4 Past and Current Population Growth are very Different
Perspectives on Population Growth
Many factors Determine Population Growth
Fertility is Influenced by Culture
A demographic Transition can lead to Stable Population Size
Family Planning Gives Us Choices
What Kind of Future Are we Creating Now?
Chapter 14 Cities are places of Crisis and Opportunity
Urban Planning
Economics and Sustainable Development
Natural Resource Accounting
Trade, Development and Jobs
Green Business and Green Design
Chapter 13 What Waste do we Produce??
Waste disposal methods
Shrinking the Waste Stream
Hazardous and Toxic Wastes
Chapter 9 What is the Atmosphere?
Climate Changes over Time, Is it changing faster?
Envisioning Solutions/Air Pollution
Past and Current Population Growth are very Different
Globally, the growth rate of the human population has been declining since peaking in 1962 and 1963 at 2.20% per annum. In 2009, the estimated annual growth rate was 1.1%. The CIA World Fact book gives the world annual birthrate, mortality rate, and growth rate as 1.915%, 0.812%, and 1.092% respectively The last one hundred years have seen a rapid increase in population due to medical advances and massive increase in agricultural productivity made possible by the Green Revolution.
The actual annual growth in the number of humans fell from its peak of 88.0 million in 1989, to a low of 73.9 million in 2003, after which it rose again to 75.2 million in 2006. Since then, annual growth has declined. In 2009, the human population increased by 74.6 million, which is projected to fall steadily to about 41 million per annum in 2050, at which time the population will have increased to about 9.2 billion. Each region of the globe has seen great reductions in growth rate in recent decades, though growth rates remain above 2% in some countries of the Middle East and Sub-Saharan Africa, and also in South Asia, Southeast Asia, and Latin America.
Some countries experience negative population growth, especially in Eastern Europe mainly due to low fertility rates, high death rates and emigration. In Southern Africa, growth is slowing due to the high number of HIV-related deaths. Some Western Europe countries might also encounter negative population growth. Japan's population began decreasing in 2005.
Population exceeding the carrying capacity of an area or environment is called overpopulation. It may be caused by growth in population or by reduction in capacity. Spikes in human population can cause problems such as pollution and traffic congestion; these might be resolved or worsened by technological and economic changes. Conversely, such areas may be considered "under populated" if the population is not large enough to maintain an economic system. Between these two extremes sits the notion of the optimum population.
Perspectives on Population Growth
Our population growth impacts other species mainly through competition for habitat and food. It impacts inanimate nature through increasing use of topsoil, pasture, forest, and waters, often in irreversible ways like wind- and water-erosion, salinization, coastal salt-water intrusion, desertification and pre-empting of lands and waters through paving, mining, drilling, damming, over-pumping of ground- and surface-water sources, draining of wetlands, siltation, and air and water pollution, particularly toxic pollution.
An environmental perspective recognizes that long-term sustainable population numbers are limited by the essential, ecosystem services that nature can provide renewably. And it recognizes that U.S. numbers have exceeded that limit since the 1950s. Government policies which directly or indirectly encourage increase in U.S. population are therefore irresponsible, rob the future and must be rejected.
Our culture also plays a very big role in weather we end up procreating or not. Here are some photos...would this type of environment effect the way you think? Or really make you think!
I can almost bet if we had more of this attitude here in the U.S. the growth rate would be different. These pictures are from a very well off restaurant called Cabbages and Condoms. It is in Thailand where their growth rate has dropped to well below 2%.
What is the carrying capacity of Earth for humans? This question has been asked for more than 300 years by scientists interested in demography. The first known estimate for the carrying capacity of Earth was made by Anton van Leeuwenhoek in 1679. Since then, the estimates of carrying capacity have varied from less than 1 billion to over 1,000 billion (a trillion people). The average of the various estimates is around 10-15 billion. Why should these estimates of carrying capacity be so variable?
Carrying capacity is difficult to estimate, and the scientists who produce these estimates use different methods to get their answers. Some researchers use curves like that produced by the logistic equation (see Figure) to predict the future maximum of the human population. Others generalize from existing "maximum" population density and multiply this by the area of land that could be inhabited. Still other estimates are based on a single assumed population constraint such as food. Basing carrying capacity on food as the limiting factor is one promising approach. However, such estimates are limited by the assumptions required about the amount of available farmland, the average yield of crops, the prevalent diet (vegetarian or meat eating), and the number of calories to be provided to each person each day.
Conventional analysts often argue that trade and technology expand ecological carrying capacity. This is a misconception. Even in the best of circumstances, technological innovation does not increase carrying capacity per se but only the efficiency of resource use. In theory, shifting to more energy- and material-efficient technologies should enable a defined environment to support a given population at a higher material standard, or a higher population at the same material standard, thereby seeming to increase carrying capacity. However, in either case, the best we could hope for in an increasingly open global economy would be to maintain total human load constant in the vicinity of carrying capacity -- the latter would still ultimately be limiting.
“A growing population can naturally create temporary shortages of certain raw materials, goods and services. Innovators and entrepreneurs can be drawn to extract resources and to produce and distribute more goods in ways that sustain the natural environment and contribute to human development. At the end of this creative process, you will have more goods available at lower prices, precisely because of population growth,” -- Steven Mosher
Many factors Determine Population Growth
Globally, people are using about 25% more natural resources than the planet can replace. In the UK, we’re consuming three times our fair share of the planet’s natural resources. We face an ‘ecological overshoot’ that will have severe consequences for both people and nature unless we humans change the way we live. Some 70% of humanity’s global footprint arises from carbon emissions; other pressures are linked to commodities such as crops, meat, fish and wood, and the freshwater we take from rivers and lakes. If we are going to change the way we live, we need to learn to live differently. The way in which we educate our children is central to this change. Childhood is the period in life when most values are learned, and the knowledge and skills for living in our fast-changing world are developed.
The Crude Birth Rate and Crude Death Rate are both measured by the rate of births or deaths respectively among a population of 1000. The CBR and CDR are determined by taking the total number of births or deaths in a population and dividing both values by a number to obtain the rate per 10000. The term total fertility rate is used to describe the total number of children the average women in a population is likely to have based on current birth rates throughout her life. The number, which ranges from more than 7 children per woman in developing countries in Africa, to around 1 child per woman in Eastern European and highly-developed Asian countries.
Of the 180 countries in the world today, some 36, with a combined population of 700 million people, have made it. With births and deaths essentially in balance, they have reached population stability. This leaves more than 140 countries—and 5.6 billion people—still staggering. Many with rising incomes and steadily declining birth rates are moving toward the population stability of the safe zone. Among them are China, Thailand, South Korea, and Iran. But many others in this group are not doing as well. After two generations of rapid growth, progress has largely come to a standstill. Living conditions in these largely rural societies are either improving very little or are deteriorating as family plots, divided and then subdivided, have left many families with too little land to sustain them.
Advocates of anti-aging research say that working longer might not be such a bad thing. With skilled workers remaining in the workforce longer, economic productivity would go up. And if people got bored with their jobs, they could switch careers. While opinions differ wildly about what the ramifications for society will be if the human lifespan is extended, most ethicists agree that the issue should be discussed now, since it might be impossible to stop or control the technology once it's developed.
Fertility is Influenced by Culture
Children are some of the most charming little people I know: full of wonder, curiosity and innate kindness. Properly nurtured, they become equally charming adults. Desiring children with the man you love is as natural as breathing. Raising a family may be the most rewarding thing some people ever do. Kids may be the only support for an older parent in a society with no social security system. Male pride is linked to having a lot of children, not just in foreign countries either! In many societies women have no control over their fertility or how many children they have.
Okay not saying more educated people with money have less children because they have other things to do besides raise children, but it could be perceived that way. People in less developed countries don't have the costs we have in more developed countries to raise kids. It seems as though their attitude is "what's one more". We might think this is wrong for our environment but actually American kids will leave a bigger footprint on earth then one of these children! Of course it should be common knowledge that social conditions change the birth and death rates.
A demographic Transition can lead to Stable Population Size
The "Demographic Transition" is a model that describes population change over time. It is based on an interpretation begun in 1929 by the American demographer Warren Thompson, of the observed changes, or transitions, in birth and death rates in industrialized societies over the past two hundred years or so. Where fertility and mortality are equal, the stable population is stationary. Basically it is complete when population growth stops!
Improving the status of women also enhances their decision-making capacity at all levels in all spheres of life, especially in the area of sexuality and reproduction. This, in turn, is essential for the long-term success of population programs. During the 1970s and 1980s, researchers repeatedly documented, using cross-sectional data from representative surveys, consistent empirical associations between various commonly used proxies for women’s status such as education and work status and their fertility, in a wide range of developing countries from different regions. . The implications of these studies were clear: improved educational and formal employment opportunities for women would lead to growing proportions of women completing primary schooling and going on to secondary schooling, and, somewhat later, would lead to greater numbers of women participating in modern-sector employment. These collective changes would be expected to push a larger proportion of women into the low fertility camp, with the result being a fertility transition.
Family Planning Gives Us Choices
Family planning is the planning of when to have children, and the use of birth control and other techniques to implement such plans. Other techniques commonly used include sexuality education, prevention and management of sexually transmitted infections, pre-conception counseling and management, and infertility management. Family planning is sometimes used as a synonym for the use of birth control; however, it often includes a wide variety of methods, and practices that are not birth control. It is most usually applied to a female-male couple who wish to limit the number of children they have and/or to control the timing of pregnancy (also known as spacing children). Family planning may encompass sterilization, as well as abortion. Family planning services are defined as "educational, comprehensive medical or social activities which enable individuals, including minors, to determine freely the number and spacing of their children and to select the means by which this may be achieved."
Methods of birth control have been around for centuries. Citric acid is said to have spermicidal properties, and women used to soak sponges in lemon juice before inserting them vaginally. Queen Anne’s Lace is also known as wild carrot, and its seeds have long been used as a contraceptive—Hippocrates described this use over two millennia ago. Pennyroyal is a plant in the mint genus and has a fragrance similar to that of spearmint. The ancient Greeks and Romans used it as a cooking herb and a flavoring ingredient in wine. They also drank pennyroyal tea to induce menstruation and abortion—1st-century physician records this use of pennyroyal in his massive five-volume encyclopedia on herbal medicine. Too much of the tea could be highly toxic, however, leading to multiple organ failure. Blue cohosh was traditionally used for birth control by Native Americans. Taken during early pregnancy, dong quai had the effect of causing uterine contractions and inducing abortion. Soranus, a gynecologist from 2nd-century Greece, described Rue as a potent abortifacient, and women in Latin America have traditionally eaten rue in salads as a contraceptive and drunk rue tea as emergency contraception or to induce abortion. Cotton itself promotes its effectiveness as birth control—acacia ferments into lactic acid, a well-known spermicide—but the seed wool did serve as a physical barrier between ejaculate and cervix. Interestingly, though, women during the times of American slavery would chew on the bark of cotton root to prevent pregnancy. The seeds of the papaya could actually serve as an effective male contraceptive. Papaya seeds, taken daily, could cut a man’s sperm count to zero and was safe for long-term use.
We seem to be headed in the right direction, but are still far away from being stable. Most demographers believe sometime in the 21st century we will reach stable. We must stay on the right path and make sure we do the necessary planning to reach this goal. Here are some projections of what to expect!
Family Planning and the unmet needs of it will be a big part in determining the future growth rates. It's said every important environmental problem is because of the overpopulation. We have to change some of our ways or we are going to destroy our earth. If all of us left a footprint as big as most Americans do, we would need a few more earths to go around; That's just not possible.
Economics and Urbanization
Cities are places of Crisis and Opportunity
More then half of the population now lives in cities, and the number is approaching 75% rapidly. The merging of big cities to make mega-cities is called urban agglomerations. Cities just keep getting bigger and bigger as more people want to live in a city. Massive building projects are underway in cities to fit the populations. Various employment opportunities exist in cities, and this is part of the draw that brings the population into more urban areas. Another positive aspect of living in a city is the fact that public transportation is readily available. This is a real concern for people today with the rising costs of gasoline affecting everyone’s bottom line.
Traffic congestion, water shortages, high unemployment rates, overcrowded schools, pollution, and ecosystem disturbance are just some of the problems caused by urban sprawl. It's a constant tug-of-war for government to combat the issue of urban sprawl while trying to meet the growing needs of new housing and commercial development. Many cities lack enough affordable housing for key populations: teachers, firefighters, policemen, child care workers, janitors, entry-level manufacturing workers and technical workers, etc. Without affordable homes for people in these occupations, large cities risk their competitiveness in a global economy that requires a skilled and accessible workforce near jobs. In addition, more affordable housing means that working households spend less of their monthly income on their housing costs, leaving more disposable income to spend on goods and services in the local economy.
Urban Planning
Urban planning is a technical and political process concerned with the control of the use of land and design of the urban environment, including transportation networks, to guide and ensure the orderly development of settlements and communities. It concerns itself with research and analysis, strategic thinking, urban design, public consultation, policy recommendations, implementation and management.
distinction explains how transplanted Europeans in North America adopt the automobile to access chosen destinations spots in our cities. It also helps us understand how transplanted North Americans in the major cities of Europe suddenly find how superior public transit is compared to the automobile for metropolitan accessibility. Smart Growth helps communities grow in ways that expand economic opportunity, protect public health and the environment, and create and enhance the places that people love.
Cities are trying to be green and incorporate smart growth into their plans. There are a number of planning principles to be thought of when approaching the matter. Green isn't green unless it is smart, and smart isn't smart unless it's green. I know the green building crowd doesn’t fully accept this, labeling buildings “green” or even “net zero” in the middle of nowhere. But that doesn’t change what is right. If a project built in 2010 doesn’t have green buildings and green infrastructure, it is not worthy of our applause. It’s just not that hard anymore.
Economics and Sustainable Development
Sustainable development is a pattern of growth in which resource use aims to meet human needs while preserving the environment so that these needs can be met not only in the present, but also for generations to come. The term sustainable development was used by the Brundtland Commission which coined what has become the most often-quoted definition of sustainable development as development that meets the needs of the present without compromising the ability of future generations to meet their own needs.
Classical economics is widely regarded as the first modern school of economic thought. Neoclassical economics is a term variously used for approaches to economics focusing on the determination of prices, outputs, and income distributions in markets through supply and demand, often mediated through a hypothesized maximization of utility by income-constrained individuals and of profits by cost-constrained firms employing available information and factors of production, in accordance with rational choice theory. Ecological economics is a trans disciplinary field of academic research that aims to address the interdependence and coevolution of human economies and natural ecosystems over time and space.
Scarcity of resources, scarcity of political consensus and scarcity of financing for innovation. These are some of the major challenges faced by companies in today’s global environment. An open access system allows no rules to manage resource use. We have to quit being so greedy and figure out what is best for us and what is best for earth.
Natural Resource Accounting
Cost-Benefit Analysis (CBA) estimates and totals up the equivalent money value of the benefits and costs to the community of projects to establish whether they are worthwhile. These projects may be dams and highways or can be training programs and health care systems. A cost benefit analysis is done to determine how well, or how poorly, a planned action will turn out. Although a cost benefit analysis can be used for almost anything, it is most commonly done on financial questions. Since the cost benefit analysis relies on the addition of positive factors and the subtraction of negative ones to determine a net result, it is also known as running the numbers.
The genuine progress indicator (GPI) is an attempt to measure whether a country's growth, increased production of goods, and expanding services have actually resulted in the improvement of the welfare (or well-being) of the people in the country. GPI advocates claim that it can more reliably measure economic progress, as it distinguishes between worthwhile growth and uneconomic growth.
The Human Development Index (HDI) is a composite statistic used to rank countries by level of "human development", taken as a synonym of the older term standards of living or Quality of life, and distinguish "very high human development", "high human development", "medium human development", and "low human development" countries. HDI was devised and launched by Pakistani economist Mahbub ul Haq and Indian economist Amartya Sen in 1990.[1] The Human Development Index (HDI) is a comparative measure of life expectancy, literacy, education, and standards of living for countries worldwide. It is a standard means of measuring well-being, especially child welfare. It is used to distinguish whether the country is a developed, a developing or an under-developed country, and also to measure the impact of economic policies on quality of life. There are also HDI for states, cities, villages, etc. by local organizations or companies. Below image shows the HDI for 2007.
Trade, Development and Jobs
Without trade we would not have development and jobs. We take advantage of our environment and where things come from, for cheaper or less. I agree with some of our exporting manufacturing and importing goods. I don't want to deny a young mother from supporting her family by working at a factory in Malaysia. I do however think she should be making more then pennies on the dollar that they would pay here. It is obviously over my head a bit how some can have too much really and some nothing at all.
Microlending is making a small loan to help someone survive, start their small business or improve their small business.Compared to traditional lending practices found in capitalist economies, microlenders are mindlessly risky in the loans they make: They loan money to the indigent, those without collateral, career changers and those without any work experience. To some, the concept of microlending is merely a noble idea that doesn't work in practice or an innovation that will eventually lead to a developed, globalized world. I think it is a superb idea and enjoy the fact it enhances dignity, respect, and cooperation.
Green Business and Green Design
Sustainable business, or green business, is an enterprise that has no negative impact on the global or local environment, community, society, or economy; A business that strives to meet the triple bottom line. Often, sustainable businesses have progressive environmental and human rights policies. In general, business is described as green if it matches the following four criteria:
It incorporates principles of sustainability into each of its business decisions.
It supplies environmentally friendly products or services that replace demand for
nongreen products and/or services.
It is greener than traditional competition.
It has made an enduring commitment to environmental principles in its business operations.
Going green seems to be a new wave that all of our business's should have no reason not to switch. This website http://www.theultimategreenlist.com/ will give you anything you want from a green company! Shopping here would be doing your part in green shopping! Operating a building is is one of our biggest uses of energy and resources. Architects are getting on the green bandwagon too. With this information out there I don't see a reason a building would be build without being green? Green home design is determined by how a structure is built, not a particular style or look. Whether your dream home is southern colonial or whimsical contemporary, it can be green. The focus is on five main factors: energy efficiency, water conservation, material selections, indoor air quality and site treatment. Here are some green homes/cars and what's to come with the new green.
http://weburbanist.com/2008/11/23/future-green-design-technology/?ref=search
http://weburbanist.com/2008/11/23/future-green-design-technology/?ref=search
Going green seems to be a new wave that all of our business's should have no reason not to switch. This website http://www.theultimategreenlist.com/ will give you anything you want from a green company! Shopping here would be doing your part in green shopping! Operating a building is is one of our biggest uses of energy and resources. Architects are getting on the green bandwagon too. With this information out there I don't see a reason a building would be build without being green? Green home design is determined by how a structure is built, not a particular style or look. Whether your dream home is southern colonial or whimsical contemporary, it can be green. The focus is on five main factors: energy efficiency, water conservation, material selections, indoor air quality and site treatment. Here are some green homes/cars and what's to come with the new green.
Environmental regulations are frequently seen as being in tension with robust employment. There is evidence, though, suggesting that environmental protection can provide economic boons, including job creation. Green businesses often create more jobs and stimulate the economy. China has taken the lead in sustainable energy...we shouldn't be far behind them, but are lacking.
Solid and Hazardous Waste
What Waste do we Produce??
Waste Disposal Methods
WE all know our 3 R's Reduce, Reuse and Recycle, we have been working on this problem for a while and need some simple solutions that will stick. Most developed countries forbid open dumping, even though illegal dumping is still a problem, but for the other countries there is no other way, making working situations unhealthy. We have put an end to ocean dumping here in the U.S. but it still is a problem for our earth. Plastic is the growing problem for the ocean and it's creatures. It is caught by the ocean in large numbers and harms it's animals.
The Great Pacific Garbage Patch, also described as the Pacific Trash Vortex, is a gyre of marine litter in the central North Pacific Ocean. The patch extends over an indeterminate area, with estimates ranging very widely depending on the degree of plastic concentration used to define the affected area.
The Patch is characterized by exceptionally high concentrations of pelagic plastics, chemical sludge, and other debris that have been trapped by the currents of the North Pacific Gyre. Despite its size and density, the patch is not visible from satellite photography, since it consists primarily of suspended particulates in the upper water column. Since plastics break down to ever smaller polymers, concentrations of submerged particles are not visible from space, nor do they appear as a continuous debris field. Instead, the patch is defined as an area in which the mass of plastic debris in the upper water column is significantly higher than average.
We are using landfills to bury our garbage. We only bury about 50% of our MSW today as opposed to around 90% 50 years ago. Our modern sanitary landfills are supposed to contain the waste. There is a lot of effort to try and make these areas safe but it is still a landfill. Because it is so expensive to dump the waste at a landfill people are shipping them off to other countries. Really? this is just crazy, we must start being more green! E-waste is consistent of our electronics that are discarded.
Energy Recovery uses the heat from incinerators burning garbage to produce energy, a useful resource. The EPA has found very high levels of toxins in the air at these burn sites. Toxins are more concentrated in the ash. Burning everything in mass burns seems like a very risky business. A mass burn is when everything is dumped to burn, all kinds of items from couches to refrigerators.
Shrinking the Waste Stream
San Francisco is aiming for 100% recycling. This is a best effort from their city, and also reduces their waste bills. Recycling saves money, energy, raw materials, and land space, and it reduces pollution. Recycling is the reprocessing of discarded materials and making them into new products or even the same products. Old cans and bottles can be melted and recast to become new cans and bottles. Composting is another form of recycling which has proven to have excellent results. Composting consists of the biological degradation of organic matter, which can then be used to supplement the soil. The compost helps the soil retain water, slow soil erosion, and improves crop yields. Reusing materials in their present form is the best conservation method possible. The perfect example of “reusing” is auto parts that you can reuse for your car sold in junk yards. In addition, stained glass windows, woodwork, bricks, and even lumber can be reused. Reducing the amount of waste we have is our next goal. The excessive packing of our foods and consumer products is our greatest unnecessary waste. This makes up about 50% of our trash by volume.
Hazardous and Toxic Wastes
Unfortunately, the waste stream contains hazardous toxic waste that can harm both humans and the environment. 40 million metric tons (22billion lbs) of toxic waste is released into the air, water, and land each year in the U. S. The largest sources of contamination come from the chemical and petroleum industries. Most hazardous waste is stored, recycled, or changed into nonhazardous forms of waste. What can we do to control hazardous waste? We can learn to produce less hazardous waste by changing or modifying our manufacturing processes so that waste production is eliminated.
Another step to take in the reduction of hazardous waste is to convert to less hazardous substances. Physical treatments isolate substances so they are not so toxic. Incineration can be used to reduce the toxicity of substances. Chemical processing can also help to neutralize hazardous waste. Because some of the materials we use cannot be destroyed, we must store them permanently. This can be done with the use of secure landfills. A secure landfill stores the chemicals or toxins in a contained area where the toxins cannot get out. Hazardous wastes are any material, liquid or solid that contains material fatal to humans, toxic, carcinogenic, mutagenic, or teratogenic to life forms.
Federal legislation regulates this hazardous waste. These two laws control it's disposal, The Resource Conservation Recovery Act, and The Comprehensive Environmental Response, Compensation and Liability Act. There is a list called the Toxic Release Inventory, that tells where regulated materials are handled. We are scheduled to have some of our 36,000 badly contaminated sites, cleaned up.
Air: Climate and Pollution
What is the Atmosphere?
The atmosphere of our earth contains gas molecules densely packed at the surface and thinning gradually to about 500 km or 300 miles about the earth’s surface. Clean, dry air contains 78% nitrogen, 21% oxygen, and the last 1% contains argon, carbon dioxide and other miscellaneous gasses. Water vapor, which is water in gas form, differs from 0 to 4%, figuring on the air temperatures and moisture levels. Tiny particles and liquid drops are called aerosols, which are suspended in the air.
The first layer of the atmosphere is made out of the gases that we breath everyday. This layer is called the troposphere. The troposphere is the layer that we live in. The next layer of our atmosphere is called the stratosphere. Above the stratosphere lies the mesosphere, followed by the thermosphere, and finally the exosphere. The mesosphere and thermosphere are often referred to together as the ionosphere because of the way they reflect the ionized energy of the Sun. In order to help scientists identify the border between each of these layers, scientists have given special names to the boundaries between a number of them. The boundary between the troposphere and the stratosphere is referred to as the tropopause. The border between the stratosphere and the mesosphere is called the stratopause. And the line separating the mesosphere from the thermosphere is called the mesopause.
Climate Changes over Time, Is it changing faster?
The greenhouse gases methane, carbon dioxide, and nitrous oxide are powering the changes, and it is produced by the actions of man, therefore mankind is causing the acceleration of climate change. Despite the overwhelming evidence, not everyone believes the theory, because popular media is spreading misinformation. In any case fixing the problem is cheaper than the results of global climate change.
Air Pollution/Envisioning Solutions
Smog hanging over cities is the most familiar and obvious form of air pollution. But there are different kinds of pollution—some visible, some invisible—that contribute to global warming. Generally any substance that people introduce into the atmosphere that has damaging effects on living things and the environment is considered air pollution.Carbon dioxide, a greenhouse gas, is the main pollutant that is warming Earth. Though living things emit carbon dioxide when they breathe, carbon dioxide is widely considered to be a pollutant when associated with cars, planes, power plants, and other human activities that involve the burning of fossil fuels such as gasoline and natural gas. In the past 150 years, such activities have pumped enough carbon dioxide into the atmosphere to raise its levels higher than they have been for hundreds of thousands of years.
Other greenhouse gases include methane—which comes from such sources as swamps and gas emitted by livestock—and chlorofluorocarbons (CFCs), which were used in refrigerants and aerosol propellants until they were banned because of their deteriorating effect on Earth's ozone layer. Another pollutant associated with climate change is sulfur dioxide, a component of smog. Sulfur dioxide and closely related chemicals are known primarily as a cause of acid rain. But they also reflect light when released in the atmosphere, which keeps sunlight out and causes Earth to cool. Volcanic eruptions can spew massive amounts of sulfur dioxide into the atmosphere, sometimes causing cooling that lasts for years. In fact, volcanoes used to be the main source of atmospheric sulfur dioxide; today people are.
Most people agree that to curb global warming, a variety of measures need to be taken. On a personal level, driving and flying less, recycling, and conservation reduces a person’s "carbon footprint"—the amount of carbon dioxide a person is responsible for putting into the atmosphere. On a larger scale, governments are taking measures to limit emissions of carbon dioxide and other greenhouse gases. One way is through the Kyoto Protocol, an agreement between countries that they will cut back on carbon dioxide emissions. Another method is to put taxes on carbon emissions or higher taxes on gasoline, so that people and companies will have greater incentives to conserve energy and pollute less.
References
http://en.wikipedia.org 3/23/2012
http://dieoff.org/page110.htm 3/23/2012
