The garbage island
If you were to sail due west from San Francisco, California, after about 2000km you would find yourself in a very strange place. This is an area of the Pacific Ocean technically referred to as the North Pacific Gyre, but a more descriptive term is the Great Pacific Garbage Patch. You heard correct. Decades of constant oceanic currents have resulted in a huge area of the Pacific that has become a veritable black hole of human-produced waste. Oceanic currents are largely steady over the period of centuries. Since the days of colonisation, Christopher Columbus and his friends had capitalised on reliable trade winds to propel them to and from the Americas. Within these swirling, connected currents lie a few select dead spots, where the motion of the ocean is effectively nil. There are five of these so-called gyres located throughout the world. The Floating Island of Garbage was discovered surprisingly recently. The story goes, a sailor named Charles Moore was returning to Los Angles after competing in a race. Normally, seamen avoid the North Parasitic Gyre like the plague. The absence of wind makes sailing impossible, and the dearth of large critters renders the area unprofitable for fishing. On this one particular occasion in 1997, Charles Moore had a little extra time, and an outboard motor on his sailboat. He decided to take a shortcut and cross through the normally-avoided area of the sea. What he saw was astounding: plastic, plastic everywhere. Moore would later return to the area to conduct thorough investigations to quantify the extent of the mess. The actual size and trash-density of the garbage patch is somewhat debatable. The general consensus is that it is around the size of the continental US and contains floating bits of plastic that are more concentrated than plankton in some areas. While the statistics are staggering, this description may paint an inaccurate picture. The mental image I first saw was a solid layer of bags, a few meters thick, that you could walk across. While I couldn't find a decent picture of it, in reality the garbage patch is not any sort of solid surface. Aside from just the mess, more disconcerting is that the plastic is starting to work its way into the food chain. For years, chemists have sought to make increasingly robust plastics, and they have succeeded. If you were to go out and buy a bag of frozen lima beans, it would likely stay fresh for quite a while. The downside is after you eat those lima beans, the discarded bag will stay on this planet longer than you will. Polyvinylchloride, polyethylene, etc, cannot be degraded by any normal organism. Sitting out in the Pacific, baking in the sun, these polymers undergo photodegradation instead. Sunlight breaks down polymers into smaller and smaller pieces, until they get to be so small that even microscopic plankton will eat them. When the bottom of the food chain starts to eat our garbage, it's just a matter of time before it works its way into fish, birds, and eventually onto our dinner plates. If the Floating Island of Garbage is left unchecked, eventually those frozen lima beans will contain parts of the bags they come in. Because the island was discovered only recently, it has become far too large to even consider cleaning up. Compare and contrast with another environmental disaster: the Exxon Valdez oil spill in 1989. There, the spill covered a mere 28 000km2 of the ocean's surface (about 100 times smaller than the garbage patch), and cost about £1 billion or so to clean up.There has been an interest within the chemical community to make polymers that are at least somewhat biodegradable. There hasn't been a major success so far, one reason being that some of the materials are a little too biodegradable. That is, you don't want a bottle of orange juice to dissolve before you get the chance to drink it. So there's no good solution for what to do about the garbage island, other than trying not to make it worse. I won't even try to evaluate the global political and economic changes that would be needed for that. But I can say for sure that next time I'm at the shop, I'll bring my own canvas bag.
Pollution is the process of making land, water, air or other parts of the environment dirty and not safe or suitable to use. This can be done through the introduction of a contaminant into a natural environment, but the contaminant doesn't need to be tangible. Things as simple as light, sound and temperature can be considered pollutants when introduced artificially into an environment. Toxic pollution affects more than 200 million people worldwide, according to Pure Earth, a non-profit environmental organization. In some of the world's worst polluted places, babies are born with birth defects, children have lost 30 to 40 IQ points, and life expectancy may be as low as 45 years because of cancers and other diseases. Read on to find out more about specific types of pollution. Land pollution Land can become polluted by household garbage and by industrial waste. In 2014, Americans produced about 258 million tons of solid waste, according to the U.S. Environmental Protection Agency. A little over half of the waste — 136 million tons— was gathered in landfills. Only about 34 percent was recycled or composted. Advertisement Organic material was the largest component of the garbage generated, the EPA said. Paper and paperboard accounted for more than 26 percent; food was 15 percent and yard trimmings were 13 percent. Plastics comprised about 13 percent of the solid waste, while rubber, leather and textiles made up 9.5 percent and metals 9 percent. Wood contributed to 6.2 percent of the garbage; glass was 4.4 percent and other miscellaneous materials made up about 3 percent. Commercial or industrial waste is a significant portion of solid waste. According to the University of Utah, industries use 4 million pounds of materials in order to provide the average American family with needed products for one year. Much of it is classified as non-hazardous, such as construction material (wood, concrete, bricks, glass, etc.) and medical waste (bandages, surgical gloves, surgical instruments, discarded needles, etc.). Hazardous waste is any liquid, solid or sludge waste that contain properties that are dangerous of potentially harmful to human health or the environment. Industries generate hazardous waste from mining, petroleum refining, pesticide manufacturing and other chemical production. Households generate hazardous waste as well, including paints and solvents, motor oil, fluorescent lights, aerosol cans, and ammunition. Water pollution Water pollution happens when chemicals or dangerous foreign substances are introduced to water, including chemicals, sewage, pesticides and fertilizers from agricultural runoff, or metals like lead or mercury. According to the Environmental Protection Agency (EPA), 44 percent of assessed stream miles, 64 percent of lakes and 30 percent of bay and estuarine areas are not clean enough for fishing and swimming. The EPA also states that the United State's most common contaminants are bacteria, mercury, phosphorus and nitrogen. These come from the most common sources of contaminates, that include agricultural runoff, air deposition, water diversions and channelization of streams. Water pollution isn't just a problem for the United States. According to United Nations, 783 million people do not have access to clean water and around 2.5 billion do not have access to adequate sanitation. Adequate sanitation helps to keep sewage and other contaminants from entering the water supply. According to National Oceanic and Atmospheric Administration (NOAA), 80 percent of pollution in marine environment comes from the land through sources like runoff. Water pollution can also severely affect marine life. For example, sewage causes pathogens to grow, while organic and inorganic compounds in water can change the composition of the precious resource. According to the EPA, low levels of dissolved oxygen in the water are also considered a pollutant. Dissolved oxygen is caused by the decomposition of organic materials, such as sewage introduced into the water. Warming water can also be harmful. The artificial warming of water is called thermal pollution. It can happen when a factory or power plant that is using water to cool its operations ends up discharging hot water. This makes the water hold less oxygen, which can kill fish and wildlife. The sudden change of temperature in the body of water can also kill fish. According to the University of Georgia, it is estimated that around half of the water withdrawn from water systems in the United States each year is used for cooling electric power plants. "In nearly all cases, 90 percent of this water is returned to its source, where it can raise the water temperature in an area immediately surrounding the water discharge pipe. Depending on water flow, the water temperature quickly returns to ambient temperatures that do not harm fish." Donn Dears, former president of TSAugust, a not for profit corporation organization focused on energy issues, told Live Science. Nutrient pollution, also called eutrophication, is another type of water pollution. It is when nutrients, such as nitrogen, are added into bodies of water. The nutrient works like fertilizer and makes algae grow at excessive rates, according to NOAA. The algae blocks light from other plants. The plants die and their decomposition leads to less oxygen in the water. Less oxygen in the water kills aquatic animals. Air pollution The air we breathe has a very exact chemical composition; 99 percent of it is made up of nitrogen, oxygen, water vapor and inert gases. Air pollution occurs when things that aren't normally there are added to the air. A common type of air pollution happens when people release particles into the air from burning fuels. This pollution looks like soot, containing millions of tiny particles, floating in the air. Another common type of air pollution is dangerous gases, such as sulfur dioxide, carbon monoxide, nitrogen oxides and chemical vapors. These can take part in further chemical reactions once they are in the atmosphere, creating acid rain and smog. Other sources of air pollution can come from within buildings, such as secondhand smoke. Finally, air pollution can take the form of greenhouse gases, such as carbon dioxide or sulfur dioxide, which are warming the planet through the greenhouse effect. According to the EPA, the greenhouse effect is when gases absorb the infrared radiation that is released from the Earth, preventing the heat from escaping. This is a natural process that keeps our atmosphere warm. If too many gases are introduced into the atmosphere, though, more heat is trapped and this can make the planet artificially warm, according to Columbia University. Air pollution kills more than 2 million people each year, according to a study published in the journal of Environmental Research Letters. The effects of air pollution on human health can vary widely depending on the pollutant, according to Hugh Sealy, professor and director of the environmental and occupational health track at the Department of Public Health and Preventive Medicine, St. George's University, St. George's, Grenada. If the pollutant is highly toxic, the effects on health can be widespread and severe. For example, the release of methyl isocyanate gas at Union Carbide plant in Bhopal in 1984 killed over 2,000 people, and over 200,000 suffered respiratory problems. An irritant (e.g. particulates less than 10 micrometers) may cause respiratory illnesses, cardiovascular disease and increases in asthma. "The very young, the old and those with vulnerable immune systems are most at risk from air pollution. The air pollutant may be carcinogenic (e.g. some volatile organic compounds) or biologically active (e.g. some viruses) or radioactive (e.g. radon). Other air pollutants like carbon dioxide have an indirect impact on human health through climate change," Sealy told Live Science. Noise pollution Even though humans can't see or smell noise pollution, it still affects the environment. Noise pollution happens when the sound coming from planes, industry or other sources reaches harmful levels. Research has shown that there are direct links between noise and health, including stress-related illnesses, high blood pressure, speech interference, hearing loss. For example, a study bythe WHO Noise Environmental Burden on Disease working group found that noise pollution may contribute to hundreds of thousands of deaths per year by increasing the rates of coronary heart disease. Under the Clean Air Act, the EPA can regulate machine and plane noise. Underwater noise pollution coming from ships has been shown to upset whales' navigation systems and kill other species that depend on the natural underwater world. Noise also makes wild species communicate louder, which can shorten their lifespan. Light pollution Most people can't imagine living without the modern convenience of electric lights. For the natural world, though, lights have changed the way that days and nights work. Some consequences of light pollution are: Some birds sing at unnatural hours in the presence of artificial light. Scientists have determined that long artificial days can affect migration schedules, as they allow for longer feeding times. Streetlights can confuse newly hatched sea turtles that rely on starlight reflecting off the waves to guide them from the beach to the ocean. They often head in the wrong direction. Light pollution, called sky glow, also makes it difficult for astronomers, both professional and amateur, to properly see the stars. Plant's flowering and developmental patterns can be entirely disrupted by artificial light. According to a study by the American Geophysical Union, light pollution could also be making smog worse by destroying nitrate radicals that helps the dispersion of smog. Turning on so many lights may not be necessary. Research published by International Journal of Science and Research estimates that over-illumination wastes about 2 million barrels of oil per day and lighting is responsible for one-fourth of all energy consumption worldwide. Other pollution facts: Americans generate 30 billion foam cups, 220 million tires, and 1.8 billion disposable diapers every year, according to the Green Schools Alliance. According to the WHO, ambient air pollution contributes to 6.7 percent of all deaths worldwide. The Mississippi River drains the lands of nearly 40 percent of the continental United Sates. It also carries an estimated 1.5 million metric tons of nitrogen pollution into the Gulf of Mexico each year, resulting in a dead zone each summer about the size of New Jersey. Pollution in China can change weather patterns in the United States. It takes just five days for the jet stream to carry heavy air pollution from China to the United States, where it stops clouds from producing rain and snow. About 7 million premature deaths annually linked to air pollution, according to WHO. That is one in eight deaths worldwide.
Global warming is the current increase in temperature of the Earth's surface (both land and water) as well as it's atmosphere. Average temperatures around the world have risen by 0.75°C (1.4°F) over the last 100 years about two thirds of this increase has occurred since 1975.1 2 In the past, when the Earth experienced increases in temperature it was the result of natural causes but today it is being caused by the accumulation of greenhouse gases in the atmosphere produced by human activities.3 The natural greenhouse effect maintains the Earth's temperature at a safe level making it possible for humans and many other lifeforms to exist.4However, since the Industrial Revolution human activities have significantly enhanced the greenhouse effect causing the Earth's average temperature to rise by almost 1°C. This is creating the global warming we see today. To put this increase in perspective it is important to understand that during the last ice age, a period of massive climate change, the average temperature change around the globe was only about 5°C.5 6 A long series of scientific research and international studies has shown, with more than 90% certainty, that this increase in overall temperatures is due to the greenhouse gases produced by humans.7 Activities such as deforestation and the burning of fossil fuels are the main sources of these emissions. These findings are recognized by the national science academies of all the major industrialized countries.8 Global warming is affecting many places around the world. It is accelerating the melting of ice sheets, permafrost and glaciers which is causing average sea levels to rise.9 10 It is also changing precipitation and weather patterns in many different places, making some places dryer, with more intense periods of drought and at the same time making other places wetter, with stronger storms and increased flooding.11 12 These changes have affected both nature as well as human society and will continue to have increasingly worse effects if greenhouse gas emissions continue to grow at the same pace as today. What causes global warming? The cause of global warming is the increasing quantity of greenhouse gases in the our atmosphere produced by human activities, like the burning of fossil fuels or deforestation. These activities produce large amounts of greenhouse gas emissions which is causing global warming.7Greenhouse gases trap heat in the Earth's atmosphere to keep the planet warm enough to sustain life, this process is called the greenhouse effect.3 It is a natural process and without these gases, the Earth would be too cold for humans, plants and other creatures to live. The natural greenhouse effect exists due to the balance of the major types of greenhouse gases. However, when abnormally high levels of these gases accumulate in the air, more heat starts getting trapped and leads to the enhancement of the greenhouse effect. Human-caused emissions have been increasing greenhouse levels which is raising worldwide temperatures and driving global warming.3 Greenhouse gas emissions and the enhanced greenhouse effect Greenhouse gases are produced both naturally and through human activities. Unfortunately, greenhouse gases generated by human activities are being added to the atmosphere at a much faster rate than any natural process can remove them. Global levels of greenhouse gases have increased dramatically since the dawn of the Industrial Revolution in the 1750s.7 Only a small group of human activities are causing the concentration of the main greenhouse gases (carbon dioxide, methane, nitrous oxide and fluorinated gases) to rise: The majority of man-made carbon dioxide emissions is from the burning of fossil fuels such as coal and oil so that humans can power various vehicles, machinery, keep warm and create electricity. Other important sources come from land-use changes (ex: deforestation) and industry (ex: cement production).13 Methane is created by humans during fossil fuel production and use, livestock and rice farming, as well as landfills.14 Nitrous oxide emissions are mainly caused by the use of synthetic fertilizers for agriculture, fossil fuel combustion and livestock manure management.15 Fluorinated gases are used mainly in refrigeration, cooling and manufacturing applications.16 Deforestation Deforestation has become a massive undertaking by humans and transforming forests into farms has a significant number of impacts as far as greenhouse gas emissions are concerned. For centuries, people have burned and cut down forests to clear land for agriculture. This has a double effect on the atmosphere both emiting carbon dioxide into the atmosphere and simultaneously reducing the number of trees that can remove carbon dioxide from the air. When forested land is cleared, soil disturbance and increased rates of decomposition in converted soils both create carbon dioxide emissions.17This also increases soil erosion and nutrient leaching which can further reduces the area's ability to act as a carbon sink. What are the effects of global warming? Global warming is damaging the Earth's climate as well as the physical environment. One of the most visible effects of global warming can be seen in the Arctic as glaciers, permafrost and sea ice are melting rapidly. Global warming is harming the environment in several ways including: Desertification Increased melting of snow and ice Sea level rise Stronger hurricanes and cyclones Desertification Increasing temperatures around the world are making arid and semi-arid areas even more dry than before. Current research is also showing that the water cycle is changing and rainfall patterns are shifting to make areas that are already dry even drier. This is causing water shortages and an intense amount of distress to the over 2.5 million people in dry regions which are degrading into desert.18 This process is called desertification. Increased melting of snow and ice Around the world, snow and ice is melting at a much faster pace than in the past. This has been seen in the Alps, Himalayas, Andes, Rockies, Alaska and Africa but is particularly true at the Earth's poles. Perennial ice cover in the Arctic is melting at the rate of 11.5% per decade and the thickness of the Arctic ice has decreased by 48% since the 1960s.19 During the past 30 years, more than a million square miles of sea ice has vanished, an area equivalent to the size of Norway, Denmark and Sweden combined.20 The continent of Antarctica has been losing more than 100 cubic kilometers (24 cubic miles) of ice per year since 2002.21 Since 2010, the Antarctic ice melt rate has doubled.22 Sea level rise The Earth's sea level has risen by 21 cm (8 inches) since 1880.23 The rate of rise is accelerating and is now at a pace that has not been seen for at least 5000 years.24 Global warming has caused this by affecting the oceans in two ways: warmer average temperatures cause ocean waters to expand (thermal expansion) and the accelerated melting of ice and glaciers increase the amount of water in the oceans. Stronger hurricanes and cyclones Tropical cyclone activity has seen an obvious upswing trend since the early 1970s.25Interestingly, this matches directly with an observed rise in the oceans' temperature over the same period of time. Since then, the Power Dissipation Index which measures the destructive power of tropical cyclones has increased in the Pacific by 35% and in the Atlantic it has nearly doubled.26 Global warming also increases the frequency of strong cyclones. Every 1 degree C increase in sea surface temperature results in a 31% increase in the global frequency of category 4 and 5 storms.27
Forest resources Rajendra kumar -final exam
Notes made available for the students studying earth science as a course and subject Biogeography.The topics included and discussed are Importance of Forests, Exploitation – Overuse, Reasons for exploitation, Causes of deforestation, Effects of deforestation, etc. #VIT Chennai
Notes made available for the students studying earth science as a course and subject Biogeography.The topics included and discussed are Defining Carbon Sequestration, Carbon Facts, Carbon Storage Facts, Natural methods of carbon sequestration, Atmospheric Carbon, etc. #VIT Chennai
Renewable Energy Sources 1
The document attached below in the knowledge . it invovles topic such as renewable energy, comaprision of population growth , renewable energy sources , need/imp. of renewable resources , merits and demertis of conventional energy resources , merits and demerits of renewable serources , solar energy , wind energy , hydro energy , geothermal enrgy , bio mass enrgy . etc .#KIIT university
Issues related to rehabilitation