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The two gases contributing most significantly to the natural greenhouse warming of the earth are water vapor and carbon dioxide. Methane, nitrous oxide, ozone and sulfur hexafluoride are also greenhouse gases but make a smaller contribution to the greenhouse effect because their concentrations are so low.
Since the beginning of the Industrial Revolution, human activities have caused an increase in several greenhouse gases, most notably carbon dioxide, a trend most scientists believe is causing anthropogenic greenhouse warming. Over the past two centuries the concentration of carbon dioxide in our atmosphere has increased about ..........click here to read more |
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One of the most significant potential impacts of climate change is sea level rise that may cause inundation of coastal areas and islands, shoreline erosion, and destruction of important ecosystems such as wetlands and mangroves. As global temperatures increase, sea level rise already underway is expected to accelerate due to a thermal expansion of upper layers of the ocean and melting of glaciers.
Shorelines have been retreating in much of the US for well over a century; scientists have mapped this change in some areas such as Long Island and Delaware. In areas with gradually sloping coasts such as the US Atlantic and Gulf .............click here to read more |
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While we often think of climate in terms of averages, the extremes are at least as important in determining a region's climate. For example, Richmond, Virginia and San Francisco, California have nearly the same annual average temperature, but the temperature in Richmond exhibits much greater seasonal variability. Consequently the two cities have different climates.
When considering climate change predictions, we also tend to focus on means; particularly the number of degrees average global temperatures are expected to rise. But most of the potential damaging consequences relating to climate change are associated with extremes - the number of heat waves, floods, or severe storms, for example. Since extreme weather events hold great potential for loss of life and property, it is imp ...........click here to read more |
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In developed nations perhaps the greatest effects of climate change over the next century will be especially adverse impacts on nature - disappearance of many wetlands due to sea level rise and changes in climate, retreat of many forests due to climatic stress, and extinction of some species that require cold habitats. Even when species survive on our planet they may be forced to migrate toward the poles to survive. Sugar maples may disappear from New England in this century. The likely rapid shift in climatic zones from global warming, even at the low ends of climate models, will threaten habitats of many species of plant and animal life. Development pressures by humans in rich and poor countries alike are already posing great risks to the survival of many species; climate change will add to these pressures. Parks and nature preserves may be especially vulnerable to climatic stress.......click here to read more |
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The international community is currently wrestling with the need to limit greenhouse emissions in order to prevent rapid global atmospheric warming. Policymakers perceive climate protection as a long-term challenge whose principal benefits may be reaped by generations yet to be born. However, most of the concrete actions that are available to limit greenhouse gas emissions may also have significant potential to enhance local air quality and contribute to health and other non-climate related benefits right away.
Climate and air quality protection efforts in most parts of the world tend to be undertaken independently of each other. This lack of coordination has a number of drawbacks from both an economic and an environmental standpoint. Industry finds that it may be faced with multiple bite regulation where it may need in one year to make ...........click here to read more |
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Ozone is a tri-atomic form of oxygen - it has three oxygen atoms instead of the normal two. It is formed naturally in the upper levels of the earth's atmosphere by high-energy ultraviolet radiation from the sun. The radiation breaks down oxygen molecules, releasing free atoms, some of which bond with other oxygen molecules to form ozone. About 90 per cent of all ozone in the atmosphere is formed in this way, between 15 and 55 kilometers above the earth's surface - the part of the atmosphere called the stratosphere. Hence, this is known as the "ozone layer." Even in the ozone layer, ozone is present in very small quantities; its maximum concentration, at a height of about 20-25 kilometers, is only ten parts per million. High-energy radiation from the Sun not only creates it, but also breaks it down..........click here to read more |
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There is a close link between local climate and the occurrence or severity of some diseases and other threats to human health. Extreme temperatures can directly cause the loss of life. Moreover, several serious diseases appear only in warm areas. Finally, warm temperatures can increase air and water pollution, which in turn harm human health. The most direct effect of climate change would be the impacts of hotter temperatures themselves. Extremely hot temperatures increase the number of people who die on a given day for many reasons: People with heart problems are vulnerable because their cardiovascular system must work harder to keep the body cool during hot weather. Heat exhaustion and some respiratory problems increase. Higher air temperatures also increase the concentration of ozone at ground level. The natural layer of ozone in the upper atmosphere blocks harmful ultraviolet radiation from reaching the earth's surface; but in the lower ............click here to read more |
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Over the past fifty years, human ingenuity has led to technological advances in agriculture that have dramatically increased crop yields. However, despite these improvements, agriculture is still highly dependent on climate since solar radiation, temperature, and precipitation are the main drivers of crop growth. Since the industrial revolution, humans have been changing the global climate by emitting high amounts of greenhouse gases into the atmosphere, potentially resulting in higher global temperatures, changed hydrological regimes, and increased climatic variability.
Climate change over the next century may have significant effects on food supply, i.e., how much food is produced, as well as food security, i.e. how much food is available to people. How much, where, and when food supply and security will be affected by climate change are questions many scientists and policy-makers are examining............click here to read more |
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Energy is the ability to do work. It allows us to generate the electricity needed for our homes, businesses, schools and factories --for lighting, powering our household appliances such as televisions and radios, refrigerators, washing machines, air conditioners and computers. Energy enables people to travel great distances by land, air and sea. All around us, energy is what makes things move, light up, give off warmth ... in other words, energy is what makes things happen. It is what gives us the power we need to do work.
You need energy to run, hit a ball, do school work, read, take a hot bath or even to sleep - yes, even to sleep. All living things need energy to live. Where do we get this energy? From the food we eat, which has energy in it. For millions of years, humans relied on energy in their own muscles to do work. Then, it was discovered that using wood......click here to read more |
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