An 8.8 earthquake struck Chile on February 27, 2010. Over 90 aftershocks have also been recorded ranging from 4.9 to 6.9 on the Richter scale. The current known death toll now stands at 708 people. Tsunami warning have been issued for all Pacific coast regions. Hawaii is expected to experience wave surges of between 9 and 16 feet.
Chile is one of the most prosperous and stable South American countries. Chilean infrastructure was far better prepared to withstand this type of disaster than the country of Haiti, where a recent 7.0 earthquake struck.
Sunday, February 28, 2010
Wednesday, February 17, 2010
Rising Sea Levels
Earth is a dynamic planet. Plate tectonics explains volcanoes, earthquakes and tsunamis. These colossal events are sudden, deadly and destructive. But there is stealthy global event ongoing that may eventually dwarf the impact of all the plate tectonic events combined. The event is the rising sea level.
Throughout the earth’s history sea level has fluctuated in response to the earth’s average temperature. A colder planet locks up more water as ice. A warmer planet leads to less ice and higher sea levels. There are several explanations for the earth’s glacial cycle. The most popular one currently concerns the fluctuation in the earth tilt. The earth’s tilt is responsible for the seasons. But this tilt is not constant. Instead the earth wobbles like a top. The maximum tilt is 24 degrees and the minimum tilt is 22.5 degrees. It has been observed that when the tilt is at its maximum and ice age occurs. The tilt variation goes in a 40,000 year cycle causing an ice age approximately once every 100,000 years. Currently we are in warm period. The last ice age ended approximately 10,000 years ago. As the long term cycle proceeds the planet will warm. This long term cycle of global warming is being accelerated by an excess of heat trapping gases in the atmosphere.
Rising sea levels has immense implications to coastal regions where most humans reside. For example, in the United States seventy-five percent of the total population lives within 50 miles of a coast. Rising seas will increase coastal erosion, pollution, storm damage, and flooding. Coastal roads, bridges, jetties, breakwaters, docks, piers, and waterfront property will be impacted. Intruding salt water might contaminate groundwater supplies and threaten landfill and hazardous waste sites. Estuaries, tidal flats and bottom dwelling organisms are all vulnerable.
Predictions on the amount of sea level elevation range from .02 meters to 6 meters. The accepted average is in the range of .944 meters. More than two-thirds of the world's large cities are in areas vulnerable to global warming and rising sea levels, and millions of people are at risk of being swamped by flooding and intense storms. Calcutta, Dhaka, London New York, Shanghai, Amsterdam, Miami, Alexandria, Buenos Aires, Rio de Janeiro, Bangkok, Los Angeles are all cities that are imperiled by rising sea level. In term of human population 650 million people are imperiled. China, India and South East Asia have the most people at risk. Currently the most common plan to combat rising sea levels is to relocate.
Throughout the earth’s history sea level has fluctuated in response to the earth’s average temperature. A colder planet locks up more water as ice. A warmer planet leads to less ice and higher sea levels. There are several explanations for the earth’s glacial cycle. The most popular one currently concerns the fluctuation in the earth tilt. The earth’s tilt is responsible for the seasons. But this tilt is not constant. Instead the earth wobbles like a top. The maximum tilt is 24 degrees and the minimum tilt is 22.5 degrees. It has been observed that when the tilt is at its maximum and ice age occurs. The tilt variation goes in a 40,000 year cycle causing an ice age approximately once every 100,000 years. Currently we are in warm period. The last ice age ended approximately 10,000 years ago. As the long term cycle proceeds the planet will warm. This long term cycle of global warming is being accelerated by an excess of heat trapping gases in the atmosphere.
Rising sea levels has immense implications to coastal regions where most humans reside. For example, in the United States seventy-five percent of the total population lives within 50 miles of a coast. Rising seas will increase coastal erosion, pollution, storm damage, and flooding. Coastal roads, bridges, jetties, breakwaters, docks, piers, and waterfront property will be impacted. Intruding salt water might contaminate groundwater supplies and threaten landfill and hazardous waste sites. Estuaries, tidal flats and bottom dwelling organisms are all vulnerable.
Predictions on the amount of sea level elevation range from .02 meters to 6 meters. The accepted average is in the range of .944 meters. More than two-thirds of the world's large cities are in areas vulnerable to global warming and rising sea levels, and millions of people are at risk of being swamped by flooding and intense storms. Calcutta, Dhaka, London New York, Shanghai, Amsterdam, Miami, Alexandria, Buenos Aires, Rio de Janeiro, Bangkok, Los Angeles are all cities that are imperiled by rising sea level. In term of human population 650 million people are imperiled. China, India and South East Asia have the most people at risk. Currently the most common plan to combat rising sea levels is to relocate.
Wednesday, February 10, 2010
Welcome to NHS Science Topics
Hello. Whether you are in freshman science, biology, chemistry or one of the many electives that NHS offers there are many interesting issues that you will encounter during your classroom discussions. This Blog is a forum where these topics can be discussed. Your teacher may require you to respond to an open ended question here. Or maybe your teacher will use this blog as a way to award extra credit. Of course you as student may have a novel idea to utilize this blog. Blogs have become a very popular method for putting information on the internet and for debating controversial ideas. So welcome and please contribute.
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