June 13, 2007, 8:34 AM CT

NASA satellites watch as China constructs giant dam

Some call it the eighth wonder of world. Others say it's the next Great Wall of China. Upon completion in 2009, the Three Gorges Dam along Chinas Yangtze River will be the world's largest hydroelectric power generator and one of the few man-made structures so enormous that it's actually visible to the naked eye from space. NASA's Landsat satellites have provided detailed, vivid views of the dam since construction began in 1994.

The Yangtze River is the third largest river in the world, stretching more than 3,900 miles across China before reaching its mouth near Shanghai. Historically, the river has been prone to massive flooding, overflowing its banks about once every ten years. During the 20th century alone, Chinese authorities estimate that some 300,000 people were killed from Yangtze River floods. The dam is designed to greatly improve flood control on the river and protect the 15 million people and 3.7 million acres of farmland in the lower Yangtze flood plains.

Observations from the NASA-built Landsat satellites provide an overview of the dam's construction. The first image shows the region previous to start of the project. By 2000, construction along each riverbank was underway, but sediment-filled water still flowed through a narrow channel near the rivers south bank. The 2004 images show limited development of the main wall and the partial filling of the reservoir, including numerous side canyons. By mid-2006, construction of the main wall was completed and a reservoir more than 2 miles (3 kilometers) across had filled just upstream of the dam......... Posted by: Tyler      Read more         Source

June 13, 2007, 8:19 AM CT

Explaining Recent Temperature, Climate Extremes

Using an ocean of data, sophisticated mathematical models and supercomputing resources, scientists at the Department of Energy's Oak Ridge National Laboratory are putting climate models to the test with particular focus on weather extremes.

Ultimately, the new methodology developed by Auroop Ganguly and his colleagues could help determine to what extent there is a correlation between human activity and climate change. For now, however, scientists are concentrating on how climate models fare when in comparison to actual observations recorded between 1940 and 2005 and whether there are any connections between the extremes.

"Once we understand the nature of these connections our hope is that we will be able to determine if there is a relation between two extreme weather events - like heat waves and droughts," said Ganguly, a member of the Computational Sciences and Engineering Division. "We may then be able to determine whether there will be more intense storms, hurricanes or floods, and this information could perhaps be used as an early warning tool or to help develop policies."

While traditional climate models may not be particularly useful for predicting extremes in general and rainfall extremes in particular, the statistical approach outlined in the journal Advances in Water Resources represents a big step in the direction of modeling rainfall extremes from observations and climate model simulations. Ganguly, who led the research team, believes the technique opens a world of possibilities......... Posted by: Tyler      Read more         Source

June 10, 2007, 9:15 PM CT

Aquatic Systems Buried Under Antarctic Ice

The National Science Foundation (NSF) should work within the environmental framework of the international Antarctic Treaty system to develop a global scientific consensus on minimally disruptive ways to investigate one of the "last unexplored places on Earth"--a unique system of lakes, and the aquatic systems that may connect them, buried thousands of meters under the Antarctic ice sheet--as per a newly released report.

To avoid contaminating these lakes and other features, which researchers have only recently discovered and which have been cut off from the outside world for millions of years, the report calls for NSF to work with international scientific organizations and Treaty signatories to develop a management plan for any potential exploration efforts and, as part of that plan, "ensure that the environmental management of subglacial environments is held to the highest standards".

The report, "Exploration of Antarctic Subglacial Aquatic Environments: Environmental and Scientific Stewardship," was released in early May by the National Research Council of the National Academies of Science.

But before any efforts are made to take any samples, the report stresses, much more detailed surveys need to be made to catalogue the subglacial aquatic network and allow it to be afforded Treaty protection. Such a survey, while enabling the protecting of the entire system, would also allow for designating certain features more useful for scientific research and presenting less of a risk of widespread contamination of a subglacial "watershed"......... Posted by: Tyler      Read more         Source

June 10, 2007, 9:11 PM CT

Nitrate in Lake Superior

Nitrate levels in Lake Superior, which have been rising steadily over the past century, are about 2.7 percent of the way toward making the lake's water unsafe to drink, as per a research studyby University of Minnesota (UMN) researchers.

The study, funded by the National Science Foundation (NSF), is published online this week in the journal Geophysical Research Letters.

The complexity of the causes underlying the increase makes it difficult to predict when the water could become unhealthy. The trend is a concern because Lake Superior contains 10 percent of the Earth's supply of surface fresh water.

Eventhough everyone is exposed to small, harmless amounts of nitrate from eating fruits and vegetables, nitrate contamination of drinking water can expose people to harmful levels.

Too much nitrate can reduce blood levels of oxygen, which poses a risk to infants and children or adults with lung or cardiovascular disease. Consuming excess nitrate over long periods of time is also suspected of causing cancer.

A compound made from nitrogen and oxygen, nitrate is a component of agricultural fertilizers and is generated by fossil fuel combustion. Nitrate in Lake Superior has increased about five-fold since the earliest measurements in 1906......... Posted by: Tyler      Read more         Source

Fri, 08 Jun 2007 23:13:33 GMT

Want to Save the Rainforest?

Some people in the UK have come up with a unique way of saving rainforest “buy it”.

Cool Earth, a new charity aims to let people buy parts of the rainforest to protect them. The charity is the idea of the Labour MP, Frank Field, known for his corncerns about social services, and a Swedish businessman, Johan Eliasch, who already owns 400,000 acres of rainforest.

Donors have to pay 70 to protect an acre of rainforest from logging and 90 to protect an acre forest from cattle grazing.

According to Field, protecting the rainforest is the number one priority in tackling climate change. He hopes that his initiative will become a mass movement.

Field said, Cool Earth is a way to enable people do something to protect forests that also provides local employment. The charity gives hold of land to local people who could indulge in income-generating activities like rubber tapping without harming the forest.

The project is backed by eminent personalities including Tony Blair.

Blair said:

Governments have a key role to play in tackling global warming, but alone, they are not enough. Only with people and Governments working together can we save the planet from catastrophe.

Fifty million acres of rainforest are cut down every year. This is equivalent to the size of Britain. The cutting of these rainforest finally result in carbon dioxide emissions more than that emitted by the largest carbon dioxide emitter on the planetthe US.

With climate change threatening the existence of several species including the Homo Sapiens, it is the duty of the wise man to save the planet. This is possible only when common people fell the urgency of fixing the problem of pollution, deforestation and greenhouse gases emissions. Though saving trees from being cut down won’t be able to set the climate change right, it will surely make a dent in the global carbon emissions. This is surely a welcome move.

Source: Telegraph

Image Source: www.uwsp.edu Posted by: Bahadurshahzafar      Read more     Source

June 7, 2007, 7:25 PM CT

Who needs environmental monitoring?

We monitor the stock market, the weather, our blood pressure. Yet environmental monitoring is often criticized as being unscientific, expensive, and wasteful. Researchers argue that environmental monitoring is a crucial part of science in the review, Who needs environmental monitoring" Gary Lovett (Institute of Ecosystem Studies) and his colleagues from several universities and US government offices contributed to the review.

The review is especially relevant, given the budgetary constraints on current monitoring and the ongoing debate regarding the opportunities, limitations, and costs linked to the establishment of national environmental observatories in the US. These include the upcoming National Ecological Observatory Network, as well as established ecological monitoring programs such as those run by the Environmental Protection Agency and face imminent closure unless Congress reverses the Agencys budgetary Plans that monitor air pollution and acid rain.

Long-term monitoring programs help society understand environmental issues including acid rain deposition, clean air, ozone, global warming, and invasive species.

As per Lovett et al., the absence of monitoring can greatly hinder evaluation of the effectiveness of environmental policies and programs......... Posted by: Tyler      Read more         Source

June 6, 2007, 9:59 PM CT

Dirty snow may warm Arctic

The global warming debate has focused on carbon dioxide emissions, but researchers at UC Irvine have determined that a lesser-known mechanism - dirty snow - can explain one-third or more of the Arctic warming primarily attributed to greenhouse gases.

Snow becomes dirty when soot from tailpipes, smoke stacks and forest fires enters the atmosphere and falls to the ground. Soot-infused snow is darker than natural snow. Dark surfaces absorb sunlight and cause warming, while bright surfaces reflect heat back into space and cause cooling.

"When we inject dirty particles into the atmosphere and they fall onto snow, the net effect is we warm the polar latitudes," said Charlie Zender, associate professor of Earth system science at UCI and co-author of the study. "Dark soot can heat up quickly. It's like placing tiny toaster ovens into the snow pack".

The study appears this week in the Journal of Geophysical Research.

Dirty snow has had a significant impact on climate warming since the Industrial Revolution. In the past 200 years, the Earth has warmed about.8 degree Celsius. Zender, graduate student Mark Flanner, and their colleagues calculated that dirty snow caused the Earth's temperature to rise.1 to.15 degree, or up to 19 percent of the total warming......... Posted by: Tyler      Read more         Source

June 1, 2007, 9:31 PM CT

connecting climate change, origins of agriculture in Mexico

New charcoal and plant microfossil evidence from Mexicos Central Balsas valley links a pivotal cultural shift, crop domestication in the New World, to local and regional environmental history. Agriculture in the Balsas valley originated and diversified during the warm, wet, postglacial period following the much cooler and drier climate in the final phases of the last ice age. A significant dry period appears to have occurred at the same time as the major dry episode linked to the collapse of Mayan civilization, Smithsonian scientists and his colleagues report in the Proceedings of the National Academy of Sciences online.

Our climate and vegetation studies reveal the ecological settings in which people domesticated plants in southwestern Mexico. They also emphasize the long-term effects of agriculture on the environment, said Dolores Piperno, curator of archaeobotany and South American archaeology at the Smithsonians National Museum of Natural History and the Smithsonian Tropical Research Institute in Panama.

Pipernos co-authors include Enrique Moreno and Irene Holst, research assistants at STRI; Jose Iriarte, lecturer in archaeology at the University of Exeter in England; Matthew Lachinet, assistant professor at the University of Nevada in Las Vegas; John Jones, assistant professor at Washington State University; Anthony Ranere, professor at Temple University; and Ron Castanzo, research collaborator at the National Museum of Natural History......... Posted by: Tyler      Read more         Source

May 31, 2007, 11:58 PM CT

evidence tropical cyclones have climate-control role

Purdue University scientists have found evidence that tropical cyclones and hurricanes play an important role in the ocean circulation patterns that transport heat and maintain the climate of North America and Europe.

These findings support a 2001 theory by Kerry Emanuel, a professor of atmospheric science at Massachusetts Institute of Technology, and suggest that there is an additional factor to be included in climate models that may change predictions of future climate scenarios.

"It was thought that hurricanes occurred over too short of a time period and over too small of an area to affect the global system," said Matthew Huber, the Purdue University professor of earth and atmospheric sciences who led the research group. "This research provides evidence that hurricanes play an important role and may be one of the missing pieces in the climate modeling puzzle".

The research also showed that hurricanes cool the tropics, forming in response to higher temperatures and acting as a thermostat for the area, Huber said.

"Warm water fuels hurricanes, which have been shown to leave cold water in their wake," said Huber, who also is a member of the Purdue Climate Change Research Center at Discovery Park.

"I like to say the good news is that hurricanes function like a thermostat for the tropics, and the bad news is that hurricanes function like a thermostat for the tropics. The logical conclusion of this finding, taking into account past research into the impact of rising temperatures on cyclone and hurricane intensity, is that as the world and the tropics warm, there will be an increase in the integrated intensity of hurricanes."........ Posted by: Tyler      Read more         Source

May 30, 2007, 0:05 AM CT

Days Of Snow Melting On The Rise In Greenland

In 2006, Greenland experienced more days of melting snow and at higher altitudes than average over the past 18 years, as per a new NASA-funded project using satellite observations.

Daily satellite observations have shown snow melting on Greenlands ice sheet over an increased number of days. The resulting data help researchers understand better the speed of glacier flow, how much water will pour from the ice sheet into the surrounding ocean and how much of the suns radiation will reflect back into the atmosphere.

"We now have the ability to monitor melting snow on Greenlands ice sheet on a daily basis using sensors on satellites measuring the electromagnetic signal naturally emitted by the ice sheet," said Marco Tedesco, research scientist at the Joint Center for Earth Systems Technology cooperatively managed by NASAs Goddard Space Flight Center, Greenbelt, Md., and the University of Maryland at Baltimore County, Baltimore.

"The sensors detected that snowmelt occurred more than 10 days longer than the average over certain areas of Greenland in 2006," said Tedesco, who is lead author of the study, which appears in the May 29 issue of the American Geophysical Union's Eos.

Tedesco applied a new method for detecting melting snow to data from the Special Sensor Microwave Imaging radiometer (SSM/I) flying aboard the Defense Meteorological Satellite Program spacecraft. The sensor can see through clouds and does not require sunlight to make measurements, providing scientists with multiple daily observations. Tedesco has updated the results annually since 1988, which has enabled him to analyze trends in the duration of snowmelt and extent over specific areas of Greenland......... Posted by: Tyler      Read more         Source