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Learn About Climate Change |
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Global Climate Change - Facts and Information
Global warming refers to the gradual increase in the temperature of the Earth's surface resulting from human caused changes in the Earth's atsmophere beginning in the industrial revolution. A warmer Earth will lead to global climate changes including changing rainfall patterns, intense storms, rising sea level, and a wide range of impacts on plants, wildlife, and humans.
Some global warming can be caused by natural factors, but a marked increase in the earth’s temperatures has been directly linked to human activity as a result of the "greenhouse" gases that we produce, primarily through consumption of fossil fuels. The contribution of the Intergovernmental Panel on Climate Change 4th Assessment Report [Working Group III] states that "Global greenhouse gas (GHG) emissions have grown since pre-industrial times, with an
increase of 70% between 1970 and 2004."
According to the Intergovernmental Panel on Climate Change 4th Assessment Report, Earth has gotten almost 1F degree hotter over the past 30 years and will increase another degree due to greenhouse gas pollution already in the atmosphere. Eleven of the past twelve years represent the hottest years on record since 1850 (IPCC, 4th Assessment)). Click here to view a chart of global surface temperature trends from 1850-2005. If the trend of increasing global temperatures doesn't end soon, we will see dramatic climate changes and potentially a far different planet. The last time the Earth was 4 or 5 degrees warmer -- 3 million years ago -- there was no ice in the Arctic and sea levels were 80 feet higher. (Hansen, 2/26/2007; NRDC, 2007)
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Earlier this year, the U.N. Intergovernmental Panel on Climate Change -- an international network of over 2,000 climate scientists -- concluded that evidence of global warming is "unequivocal" and human activity is "very likely" the cause (IPCC, 4th Assessment). |
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In April of 2007, the IPCC reported that, without changes in human behavior, within decades climate change could cause hundreds of millions of people to suffer water shortages and tens of millions to be flooded out of their homes annually. By 2080, hundreds of millions could starve (IPCC, 4th Assessment). |
Natural Greenhouse Effect
There is a natural greenhouse effect that is absolutely vital to allowing life, as we know it, to survive on earth. This natural greenhouse effect is primarily due to the natural carbon cycle which produces and sequesters CO2, and the CO2 in the atmosphere in turn acts as an insulating blanket around the Earth. Without this natural effect, the Earth would be a cold planet with average temperatures roughly 60ºF lower. (Source: US Environmental Protection Agency.) Learn more about the natural carbon cycle. In fact, if you want to know what Earth would be like without an atmosphere, check out Mars!
Anthropengenic Greenhouse Effect - Man made warming!
During the past century humans have substantially added to the amount of greenhouse gases in the atmosphere by burning fossil fuels, for example, coal, natural gas, oil and gasoline to power our cars, factories, utilities and appliances. The added gases — primarily carbon dioxide and methane — are exacerbating the natural greenhouse effect, and likely contributing to an increase in global average temperature and related climate changes - otherwise known as Global Warming. The global increases
in carbon dioxide concentration are due primarily to fossil fuel use and land-use change, while those of
methane and nitrous oxide are primarily due to agriculture. (IPCC, 4th Assessment Report). Learn more about human-related sources of CO2. |
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What are greenhouse gases (GHGs)? |
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| When scientists talk about CO2, they are describing the measurement of all greenhouse gas emissions (the primary component is CO2) in terms of CO2 equivalents. Each greenhouse gas has a unique "GWP," or Global Warming Potential. Emissions of greenhouse gases are weighted based upon their relative global warming potential
(GWP), with carbon dioxide equal to a weight of one. It’s a way of comparing apples to apples. |
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Carbon Dioxide (CO2) |
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| Carbon dioxide enters the atmosphere through the burning of fossil fuels, solid waste, trees and wood products, and also as a result of other chemical reactions (e.g., manufacture of cement). Carbon dioxide is also emitted and removed from the atmosphere (or “sequestered”) by plants as part of the biological carbon cycle. The IPCC 4th Assessment report indicated that CO2
emissions have grown between 1970 and 2004 by about 80% (28% between 1990 and
2004) and represented 77% of total anthropogenic GHG emissions in 2004. MORE CO2 facts>> |
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Methane (CH4) |
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| Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from livestock and other agricultural practices and by the decay of organic waste in municipal solid waste landfills. MORE Methane facts>> |
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Nitrous Oxide (NH2) |
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| Nitrous oxide is emitted during agricultural and industrial activities, as well as during combustion of fossil fuels and solid waste. MORE NO2 facts>> |
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Fluorinated Gases |
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| Hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride are synthetic, powerful greenhouse gases that are emitted from a variety of industrial processes. Fluorinated gases are sometimes used as substitutes for ozone-depleting substances (i.e., CFCs, HCFCs, and halons). These gases are typically emitted in smaller quantities, but because they are potent greenhouse gases, they are considered High Global Warming Potential gases (“High GWP gases”). MORE Flourinated gas facts>> |
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