Basic Information(Epa Home)
Climate Change or Global Warming? The term climate change is often used interchangeably with the term global warming, but according to the National Academy of Sciences, "the phrase 'climate change' is growing in preferred use to 'global warming' because it helps convey that there are [other] changes in addition to rising temperatures." Climate change refers to any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer). Climate change may result from: · natural factors, such as changes in the sun's intensity or slow changes in the Earth's orbit around the sun; · natural processes within the climate system (e.g. changes in ocean circulation); · human activities that change the atmosphere's composition (e.g. through burning fossil fuels) and the land surface (e.g. deforestation, reforestation, urbanization, desertification, etc.) Global warming is an average increase in the temperature of the atmosphere near the Earth's surface and in the troposphere, which can contribute to changes in global climate patterns. Global warming can occur from a variety of causes, both natural and human induced. In common usage, "global warming" often refers to the warming that can occur as a result of increased emissions of greenhouse gases from human activities. The Earth's climate has changed many times during the planet's history, with events ranging from ice ages to long periods of warmth. Historically, natural factors such as volcanic eruptions, changes in the Earth's orbit, and the amount of energy released from the Sun have affected the Earth's climate. Beginning late in the 18th century, human activities associated with the Industrial Revolution have also changed the composition of the atmosphere and therefore very likely are influencing the Earth's climate. The EPA climate change Web site has four main sections on climate change issues and another section on "What You Can Do" to reduce your contribution. A "Frequent Questions" section is available, and EPA has provided a frequent questions database where users can search for more specific questions and answers on climate change. What You Can Do (edf.org)Burning fossil fuels to power our homes and run our cars creates global warming pollution. Big and small changes can add up and make a real difference in the fight against global warming. Print out a booklet of tips [PDF] or handouts to share! At Home: Use Less Energy
On the Road: Be Efficient
When it comes to global warming, how and what we drive are two of our most powerful choices. Transportation is the biggest source of U.S. carbon dioxide emissions, more than factories or homes.
Neutralize the Rest Even if you are already driving efficiently and using less electricity, there's more you can do. Buying offsets, or credits, neutralizes what we can't cut. Global Warming Myths and Facts(Enviromental Defense Fund, edf.org) MYTH: The science of global warming is too uncertain to act on. FACT: There is no debate among scientists about the basic facts of global warming. (Joint Statement of Science Academies: Global Response to Climate Change [PDF], 2005) MYTH: Even if global warming is a problem, addressing it will hurt American industry and workers. FACT: A well designed trading program will harness American ingenuity to decrease heat-trapping pollution cost-effectively, jumpstarting a new carbon economy. Claims that fighting global warming will cripple the economy and cost hundreds of thousands of jobs are unfounded. In fact, companies that are already reducing their heat-trapping emissions have discovered that cutting pollution can save money. The cost of a comprehensive national greenhouse gas reduction program will depend on the precise emissions targets, the timing for the reductions and the means of implementation. An independent MIT study found that a modest cap-and-trade system would cost less than $20 per household annually and have no negative impact on employment. MYTH: Water vapor is the most important, abundant greenhouse gas. So if we’re going to control a greenhouse gas, why don’t we control it instead of carbon dioxide (CO2)? FACT: Although water vapor traps more heat than CO2, because of the relationships among CO2, water vapor and climate, to fight global warming nations must focus on controlling CO2. The best way to lower temperature and thus reduce water vapor levels is to reduce CO2 emissions. MYTH: Global warming and extra CO2 will actually be beneficial — they reduce cold-related deaths and stimulate crop growth. FACT: Any beneficial effects will be far outweighed by damage and disruption. Even a warming in just the middle range of scientific projections would have devastating impacts on many sectors of the economy. Rising seas would inundate coastal communities, contaminate water supplies with salt and increase the risk of flooding by storm surge, affecting tens of millions of people globally. Moreover, extreme weather events, including heat waves, droughts and floods, are predicted to increase in frequency and intensity, causing loss of lives and property and throwing agriculture into turmoil. The notion that there will be regional “winners” and “losers” in global warming is based on a world-view from the 1950’s. We live in a global community. Never mind the moral implications — when an environmental catastrophe creates millions of refugees half-way around the world, Americans are affected. MYTH: Global warming is just part of a natural cycle. The Arctic has warmed up in the past. FACT: The global warming we are experiencing is not natural. People are causing it. MYTH: We can adapt to climate change — civilization has survived droughts and temperature shifts before. FACT: Although humans as a whole have survived the vagaries of drought, stretches of warmth and cold and more, entire societies have collapsed from dramatic climatic shifts. In what appears to be the first forced move resulting from climate change, 100 residents of Tegua island in the Pacific Ocean were evacuated by the government because rising sea levels were flooding their island. Some 2,000 other islanders plan a similar move to escape rising waters. In the United States, the village of Shishmaref in Alaska, which has been inhabited for 400 years, is collapsing from melting permafrost. Relocation plans are in the works. MYTH: Recent cold winters and cool summers don’t feel like global warming to me. FACT: While different pockets of the country have experienced some cold winters here and there, the overall trend is warmer winters. Climate skeptics mislead the public when they claim that the winter of 2003–2004 was the coldest ever in the northeastern United States. That winter was only the 33rd coldest in the region since records began in 1896. Furthermore, a single year of cold weather in one region of the globe is not an indication of a trend in the global climate, which refers to a long-term average over the entire planet. MYTH: Global warming can’t be happening because some glaciers and ice sheets are growing, not shrinking. FACT: In most parts of the world, the retreat of glaciers has been dramatic. The best available scientific data indicate that Greenland's massive ice sheet is shrinking. In Greenland, a NASA satellite that can measure the ice mass over the whole continent has found that although there is variation from month to month, over the longer term, the ice is disappearing. In fact, there are worrisome signs that melting is accelerating: glaciers are moving into the ocean twice as fast as a decade ago, and, over time, more and more glaciers have started to accelerate. What is most alarming is the prediction, based on model calculations and historical evidence, that an approximately 5.4 degree Fahrenheit increase in local Greenland temperatures will lead to irreversible meltdown and a sea-level rise of over 20 feet. Since the Arctic is warming 2-3 times faster than the global average, this tipping point is not far away. MYTH: Accurate weather predictions a few days in advance are hard to come by. Why on earth should we have confidence in climate projections decades from now? FACT: Climate prediction is fundamentally different from weather prediction, just as climate is different from weather. MYTH: As the ozone hole shrinks, global warming will no longer be a problem. FACT: Global warming and the ozone hole are two different problems. The ozone hole is a thinning of the stratosphere's ozone layer, which is roughly 9 to 31 miles above the earth's surface. The depletion of the ozone is due to man-made chemicals like chlorofluorocarbons (CFCs). A thinner ozone layer lets more harmful ultraviolet (UV) radiation to reach the earth's surface. Global warming, on the other hand, is the increase in the earth's average temperature due to the buildup of CO2 and other greenhouse gases in the atmosphere from human activities. For more information, see our in-depth scientific report [PDF] on the myths and facts of global warming by Dr. James Wang and Dr. Michael Oppenheimer. Posted: 18-Jan-2007; Updated: 03-Jan-2008 Global warminghttp://www.youtube.com/watch?v=oJAbATJCugs From Wikipedia, the free encyclopediaJump to: navigation, search This article is about the current period of increasing global temperature. For other periods of warming in Earth's history, see Paleoclimatology and Geologic temperature record. Global mean surface temperature anomaly relative to 1961–1990
Mean surface temperature anomalies during the period 1995 to 2004 with respect to the average temperatures from 1940 to 1980 |
