This is the VOA Special English Agriculture Report.
Rice hulls, or husks, are the protective coverings on grains of rice. Rice with just its hull removed is brown rice. Rice without its hull or bran is white rice.
Rice hulls
Once rice is harvested, the hulls are out of a job. They may be taken to landfills or burned. Sometimes they are used to absorb waste in chicken houses. Other times they are used to amend soil.
But a chemist in Texas has another idea.
Rajan Vempati led a group that developed a new process to make rice hulls into ash. The idea is to replace some of the portland cement traditionally used in making concrete. Portland cement is a material that holds together the sand and crushed stone in concrete.
Rajan Vempati thinks rice hull ash could help the concrete industry produce less carbon dioxide. Carbon dioxide is released in cement manufacturing when fuel is burned and limestone is heated. The Portland Cement Association says the gas from the limestone is reabsorbed as concrete ages.
But cement manufacturing produces around five percent of the carbon dioxide released by human activity worldwide. Carbon dioxide is one of the gases that may affect the climate by trapping heat.
The process for making rice hull ash heats the hulls to eight hundred degrees centigrade. Carbon is driven out, and fine particles of almost pure silica remain. The process releases some carbon dioxide, but Rajan Vempati says it would be reabsorbed into the soil naturally.
Another inventor, Prasad Rangaraju, is an engineer at Clemson University in South Carolina. He tested the cement, and says less could be used because the rice hull ash makes it a stronger building material. Also, the inventors say the light-colored material better reflects sunlight, so buildings would cost less to cool.
The National Ready Mixed Concrete Association points out that using ash in cement is not a new idea. The ancient Romans discovered that volcanic ash made better cement.
But the modern inventors say rice hull ash works better than other materials. They developed the process with money from the National Science Foundation. They have not yet brought it to market.
Rice hull ash is already available, but the product is relatively costly.
Cost, including transportation, may decide the success of the new technology. Using it could make the most sense in areas where farmers grow lots of rice and the hulls might just go to waste.
And that's the VOA Special English Agriculture Report, written by Jerilyn Watson with Steve Baragona. I'm Bob Doughty.
Monday, November 30, 2009
India, US Agree on Climate Change
President Barack Obama and Prime Minister Manmohan Singh have launched what the White House is calling a green partnership, affirming the countries' commitment to combating climate change and ensuring energy security and clean energy.
India and the United States have agreed on a Memorandum of Understanding to increase cooperation on energy security, clean energy, and climate change.
Prime Minister Manmohan Singh, on a state visit to Washington, said both countries will work together to make the environment cleaner.
"We welcome the president's commitment to a major program for promotion of renewable energy, and I drew his attention to India's own ambitious national action plan on climate change which has eight national missions covering both mitigation and adaptation," Mr. Singh said.
The two leaders said their countries are committed to building a clean energy economy that will drive investment, job creation, and economic growth.
Ron Somers is president of the US-India Business Council. He says India and the United States will soon be close partners in promoting green technology.
"We will be focusing on new collaborations that are going to become platform not only for India to fight global warming or United States to fight global warming but a platform that we together develop to provide technologies for the world. So I see tremendous opportunities coming," Somers said. "It's all about low carbon emitting technology."
But India and China have rejected mandated cuts in carbon emissions. Both countries say rich, developed nations should lead the way in cutting greenhouse gases.
They argue that their economic growth would be stunted if there were mandated cuts.
The US and India have agreed that the Copenhagen climate conference, in early December, should involve targets for emission cuts for developed countries but only mitigation actions -- such as improving energy efficiency -- for developing countries.
Recently, India announced it would produce 20 Gigawatts of solar power by 2022.
Bo Kong, directs the Global Energy and Climate Initiative at Johns Hopkins University. He says that target is impossible for India.
"Within such a short time frame - we are talking about building about 20 - 20 gigawatts of power plants which translates into at least over 10,000 solar power plants between 2009 to 2020 - in less than 10 years - so I am very suspicious," Kong said.
Experts say India can only make inroads into green technology if it has financial and technological support from rich countries.
Prime Minister Singh and President Obama agreed to support public and private intiatives that will invest in clean energy projects in India.
India and the United States have agreed on a Memorandum of Understanding to increase cooperation on energy security, clean energy, and climate change.
Prime Minister Manmohan Singh, on a state visit to Washington, said both countries will work together to make the environment cleaner.
"We welcome the president's commitment to a major program for promotion of renewable energy, and I drew his attention to India's own ambitious national action plan on climate change which has eight national missions covering both mitigation and adaptation," Mr. Singh said.
The two leaders said their countries are committed to building a clean energy economy that will drive investment, job creation, and economic growth.
Ron Somers is president of the US-India Business Council. He says India and the United States will soon be close partners in promoting green technology.
"We will be focusing on new collaborations that are going to become platform not only for India to fight global warming or United States to fight global warming but a platform that we together develop to provide technologies for the world. So I see tremendous opportunities coming," Somers said. "It's all about low carbon emitting technology."
But India and China have rejected mandated cuts in carbon emissions. Both countries say rich, developed nations should lead the way in cutting greenhouse gases.
They argue that their economic growth would be stunted if there were mandated cuts.
The US and India have agreed that the Copenhagen climate conference, in early December, should involve targets for emission cuts for developed countries but only mitigation actions -- such as improving energy efficiency -- for developing countries.
Recently, India announced it would produce 20 Gigawatts of solar power by 2022.
Bo Kong, directs the Global Energy and Climate Initiative at Johns Hopkins University. He says that target is impossible for India.
"Within such a short time frame - we are talking about building about 20 - 20 gigawatts of power plants which translates into at least over 10,000 solar power plants between 2009 to 2020 - in less than 10 years - so I am very suspicious," Kong said.
Experts say India can only make inroads into green technology if it has financial and technological support from rich countries.
Prime Minister Singh and President Obama agreed to support public and private intiatives that will invest in clean energy projects in India.
European reaction has generally been positive to President Barack Obama's announcement he will attend December climate talks in Copenhagen and to Washington's provisional targets for cutting greenhouse emissions.
European leaders and environmentalists hailed as good news President Obama's decision to attend at least part of next month's climate summit in Copenhagen. Both Sweden - the current president of the European Union - and Denmark, which is hosting the climate talks, said the US leader's presence would boost expectations for the conference.
The European Union is at the forefront of a global push to reduce greenhouse gas emissions. It has pledged to cut those emissions by 20 percent of 1990 levels by 2020. By the same year, it says, 20 percent of its energy will come from renewable sources.
The Obama administration has pledged a provisional target of reducing greenhouse gasses by about 17 percent of 2005 levels by 2020 - with deeper cuts after that. The initial pledge is far less ambitious than the European one. But Mr. Obama is hamstrung by the fact the US Congress has yet to pass climate legislation.
While French Environment Minister Jean-Louis Borloo called the U.S. stance extremely encouraging, other European politicians have called on Washington to push for deeper emissions cuts.
Some also expressed disappointment that Mr. Obama was not scheduled to attend the end of the Copenhagen summit when the toughest negotiations are expected to take place. Mr. Obama is expected to arrive on December 9 - two days after the meeting starts. Joris den Blanken is European climate policy director for Greenpeace International.
"I think it's very positive that Obama announced he's coming to Copenhagen, but he's in fact coming at the the wrong day. The high-level segment in Copenhagen is the 16th and 17th of December," he said. "That's the moment where President Obama can negotiate..with European leaders like [German] Chancellor Merkel, President Sarkozy of France, Prime Minister Reinfeldt of Sweden. That's when it should happen," he said.
On Thursday, China announced its first detailed plan to ease carbon dioxide emissions. The State Councilsaid the country will reduce its "carbon intensity" by 40 to 45 percent by the year 2020, as compared to 2005 emission levels. It described the target as a voluntary action, and predicted it would make a "major contribution" to global efforts to deal with climate change.
European leaders and environmentalists hailed as good news President Obama's decision to attend at least part of next month's climate summit in Copenhagen. Both Sweden - the current president of the European Union - and Denmark, which is hosting the climate talks, said the US leader's presence would boost expectations for the conference.
The European Union is at the forefront of a global push to reduce greenhouse gas emissions. It has pledged to cut those emissions by 20 percent of 1990 levels by 2020. By the same year, it says, 20 percent of its energy will come from renewable sources.
The Obama administration has pledged a provisional target of reducing greenhouse gasses by about 17 percent of 2005 levels by 2020 - with deeper cuts after that. The initial pledge is far less ambitious than the European one. But Mr. Obama is hamstrung by the fact the US Congress has yet to pass climate legislation.
While French Environment Minister Jean-Louis Borloo called the U.S. stance extremely encouraging, other European politicians have called on Washington to push for deeper emissions cuts.
Some also expressed disappointment that Mr. Obama was not scheduled to attend the end of the Copenhagen summit when the toughest negotiations are expected to take place. Mr. Obama is expected to arrive on December 9 - two days after the meeting starts. Joris den Blanken is European climate policy director for Greenpeace International.
"I think it's very positive that Obama announced he's coming to Copenhagen, but he's in fact coming at the the wrong day. The high-level segment in Copenhagen is the 16th and 17th of December," he said. "That's the moment where President Obama can negotiate..with European leaders like [German] Chancellor Merkel, President Sarkozy of France, Prime Minister Reinfeldt of Sweden. That's when it should happen," he said.
On Thursday, China announced its first detailed plan to ease carbon dioxide emissions. The State Councilsaid the country will reduce its "carbon intensity" by 40 to 45 percent by the year 2020, as compared to 2005 emission levels. It described the target as a voluntary action, and predicted it would make a "major contribution" to global efforts to deal with climate change.
Thursday, November 26, 2009
New data show ice loss Greenland Accelerating
New data confirm the Greenland ice sheet is losing mass at an accelerating rate. The new calculations, based on state-of-the-art satellite observations combined with models of Greenland's changing icescape, are further evidence, scientists say, of the impact of global warming.
Greenland has lost about 1,500 gigatons of ice mass between 2000 and 2008, according to a new report, resulting in an average sea level rise of 0.46 millimeters per year. A gigaton is one billion tons.
Between 2006 and 2008, the authors say the rate at which Greenland's ice sheet is shrinking due to global warming accelerated, causing ocean levels to rise 0.75 millimeters per year.
The calculations are considered the most reliable to date because they combine data from the twin Gravity Recovery and Climate Experiment satellites, known as GRACE, with computer models of Greenland's changing icescape.
GRACE detects alterations in gravity caused by reductions in the ice sheet. But the calculations do not tell scientists what is causing the ice cap to shrink, says Michiel van den Broeke, a professor of polar meteorology at Utrecht University in the Netherlands.
Van den Broeke says some observations indicate sea levels are rising as the ice mass that makes up 80 percent of Greenland melts, resulting in a run-off of liquid water into the sea. Other studies suggest that rising ocean levels are caused by glacial ice that breaks off into the sea along Greenland's coast and forms icebergs.
Van den Broeke and colleagues created a model he says indicates the formation of icebergs and melting ice play equal roles in reducing the size of the Greenland Ice Sheet.
"It turns out that both increased iceberg production, because these glaciers have started to flow faster in the last 10 years, and increased melting," said Michiel van den Broeke. "They have both contributed about equally to the recent mass loss."
The study by van den Broeke and colleagues traces the beginning of Greenland's ice loss to 1996. Some experts believe if current trends continue, global sea levels will rise by a meter or more by the end of the century.
Steve Nerem, a professor of aerospace engineering sciences at the University of Colorado in Boulder says that is why it is important to refine predictions of what the Greenland Ice Sheet is going to do.
"And that is still very uncertain, which is why a paper like this is very interesting," said Steve Nerem. "Because we are really just now starting to get a handle of what the dynamics of these ice sheets are and the question is, they are almost certainly going to melt, but how quickly are they going to melt; you know, how much is going to melt in 100 years, in 1,000 years or 2,000 years."
If the entire Greenland ice sheet were to melt, Nerem says it contains enough water to cause a global sea-level rise of seven meters.
For low-lying countries to prepare, Nerem says, scientists need to know how quickly the Greenland ice mass is melting.
"If the meter in sea level rise were to happen very rapidly, say in 50 years, it will be very hard to build the infrastructure, you know the dykes - and the other things to hold back the water - quickly enough to prevent the inundation that would occur with a meter of sea-level rise," he said. "If it were to take hundreds of years, then that would probably be enough time for populated areas to build the protections that they need to combat this."
New measurements of sea level rise and ice loss in Greenland are published in the journal Science.
Greenland has lost about 1,500 gigatons of ice mass between 2000 and 2008, according to a new report, resulting in an average sea level rise of 0.46 millimeters per year. A gigaton is one billion tons.
Between 2006 and 2008, the authors say the rate at which Greenland's ice sheet is shrinking due to global warming accelerated, causing ocean levels to rise 0.75 millimeters per year.
The calculations are considered the most reliable to date because they combine data from the twin Gravity Recovery and Climate Experiment satellites, known as GRACE, with computer models of Greenland's changing icescape.
GRACE detects alterations in gravity caused by reductions in the ice sheet. But the calculations do not tell scientists what is causing the ice cap to shrink, says Michiel van den Broeke, a professor of polar meteorology at Utrecht University in the Netherlands.
Van den Broeke says some observations indicate sea levels are rising as the ice mass that makes up 80 percent of Greenland melts, resulting in a run-off of liquid water into the sea. Other studies suggest that rising ocean levels are caused by glacial ice that breaks off into the sea along Greenland's coast and forms icebergs.
Van den Broeke and colleagues created a model he says indicates the formation of icebergs and melting ice play equal roles in reducing the size of the Greenland Ice Sheet.
"It turns out that both increased iceberg production, because these glaciers have started to flow faster in the last 10 years, and increased melting," said Michiel van den Broeke. "They have both contributed about equally to the recent mass loss."
The study by van den Broeke and colleagues traces the beginning of Greenland's ice loss to 1996. Some experts believe if current trends continue, global sea levels will rise by a meter or more by the end of the century.
Steve Nerem, a professor of aerospace engineering sciences at the University of Colorado in Boulder says that is why it is important to refine predictions of what the Greenland Ice Sheet is going to do.
"And that is still very uncertain, which is why a paper like this is very interesting," said Steve Nerem. "Because we are really just now starting to get a handle of what the dynamics of these ice sheets are and the question is, they are almost certainly going to melt, but how quickly are they going to melt; you know, how much is going to melt in 100 years, in 1,000 years or 2,000 years."
If the entire Greenland ice sheet were to melt, Nerem says it contains enough water to cause a global sea-level rise of seven meters.
For low-lying countries to prepare, Nerem says, scientists need to know how quickly the Greenland ice mass is melting.
"If the meter in sea level rise were to happen very rapidly, say in 50 years, it will be very hard to build the infrastructure, you know the dykes - and the other things to hold back the water - quickly enough to prevent the inundation that would occur with a meter of sea-level rise," he said. "If it were to take hundreds of years, then that would probably be enough time for populated areas to build the protections that they need to combat this."
New measurements of sea level rise and ice loss in Greenland are published in the journal Science.
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