Greenhouse Effect
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Global warming is the observed increase in the average temperature of the Earths near-surface air and oceans in recent decades and its projected continuation. Global warming poses an extraordinary challenge. The worlds leading atmospheric scientists tell us that a gradual warming of our climate is underway and will continue. This long-term warming trend poses serious risks to our economy and our environment. It poses even greater risks to many other nations, particularly poorer countries that will be far less able to cope with a changing climate and low-lying countries where sea level rise will cause significant damage.
Relative to the period 1860-1900, global temperatures on both land and sea have increased by 1.4 oF, according to the instrumental temperature record; the urban heat island is not believed to be significant. Since 1979, land temperatures have increased about twice as fast as ocean temperatures. Temperatures in the lowest portion of the earths atmosphere (troposphere) have increased between 0.22 and 0.4 oF per decade since 1979, according to satellite temperature measurements. Over the one or two thousand years before 1850, temperature is believed to have been relatively stable, with possibly regional fluctuations such as the Medieval Warm Period or the Little Ice Age. Based on estimates by NASAs Goddard Institute for Space Studies, 2005 was the warmest year since reliable, widespread instrumental measurements became available in the late 1800s, exceeding the previous record set in 1998 by a few hundredths of a degree. Estimates prepared by the World Meteorological Organization and the UK Climatic Research Unit concluded that 2005 was the second warmest year, behind 1998 (Wilkipedia, 2006).
Species are disappearing and glaciers all around the world are melting. Animal and plant species have begun dying off or changing sooner than predicted because of global warming, a review of hundreds of research studies contends. These fast-moving adaptations come as a surprise even to biologists and ecologists because they are occurring so rapidly. At least 70 species of frogs, mostly mountain-dwellers that had nowhere to go to escape the creeping heat, have gone extinct because of climate change, the analysis says. It also reports that between 100 and 200 other cold-dependent animal species, such as penguins and polar bears are in deep trouble. Greenland has lost 20 percent more mass than it receives from new snowfall each year and it will shrink further as the planet warms. Extreme weather patterns have emerged. Examples of these weather patterns are popping up all over the world. From the hurricanes that have hit the United States to the Tsunamis that are threatening life in Asia; these patterns are a direct result of global warming. In Alaska for example scientists discovered the total surface area of the lakes water in eight of the nine study regions studied shrank by 4 to 31 percent. Whats more, the total number of lakes in all nine regions declined by 5 to 54 percent, and mean annual temperatures increased significantly (Flores 2007). The increase in the earths temperature is a direct result of greenhouse gases. Some of the most damaging greenhouse gases are fossil fuels. These gases release carbon dioxide which traps the heat that is normally released into the atmosphere. A study by researchers at the Physics Institute at the University of Bern and the European Project for Ice Coring in Antarctic presenting data from Antarctic ice cores showing carbon dioxide concentrations higher than at any time during the past 650,000 years (Inconvenient Truth, 2006). The amount of carbon dioxide (CO2) in the earths atmosphere has increased by 31% in the past 100 years (Wilkipedia, 2006). Scientists estimate that the worlds average temperature will rise by 5.80C over the next 100 years. The increase of these temperatures is causing the Polar Ice Caps to melt and sea levels to rise. If these sea levels rise as little as five feet, many of the low lying areas in the world will become submerged under water.
An increase in global temperatures can in turn cause other changes, including a rising sea level and changes in the amount and pattern of precipitation. These changes may increase the frequency and intensity of extreme weather events, such as floods, droughts, heat waves, hurricanes, and tornados. Other consequences include higher or lower agricultural yields, glacier retreat, reduced summer stream flows, species extinctions and increases in the ranges of disease vectors. Warming is expected to affect the number and magnitude of these events; however, it is difficult to connect particular events to global warming. Although most studies focus on the period up to 2100, even if no further greenhouse gases were released after this date, warming would be expected to continue to rise for more than a millennium, since Carbon Dioxide has a long average atmospheric lifetime (Wilkipedia 2006).
“Remaining scientific uncertainties include the exact degree of climate change expected in the future, and especially how changes will vary from region to region across the globe” (Wilkipedia 2006). A contested political and public debate has yet to be resolved, regarding whether anything should be done, and what could be cost-effectively done to reduce or reverse future warming, or to deal with the