VOA慢速英语:How to reduce gases linked to climate change?

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This is SCIENCE IN THE NEWS in VOA Special English. I'm Bob Doughty.

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And I'm Faith Lapidus. On our program this week, we will tell about the new United Nations report on climate change. We will also tell about an ancient burial place and a possible method to reduce blood shortages in hospitals.

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Leaders of eight industrial nations meet this week in the German town of Heiligendamm. The leaders are to discuss many issues, including the warming of the Earth. One subject is expected to be a new United Nations report. The U.N. Intergovernmental Panel on Climate Change released the report last month at a conference in Thailand.

The report says the world has the technology necessary to reduce gases that trap heat from the Sun. But it warns that action by governments and individuals must begin immediately.

Groups of experts from around the world produced the report. The groups examined scientific information needed to understand climate change. They did not carry out scientific research.

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Earlier studies have linked Earth's rising temperatures to production of heat-trapping gases like carbon dioxide. Some scientists have already said what they believe will happen if carbon dioxide emissions continue to grow. They say long-term effects will include rising sea levels, damaging storms and severe lack of rain in different areas. The scientists say this could result in extreme heat, more floods, and shortages of clean water to drink. They say it could also lead to reduced food production and more world hunger.

The new report expands on two earlier U.N. reports. The earlier reports said climate change is likely the result of human activity. They also said it threatens life on Earth.

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The new report says severe climate change can be stopped. It calls for immediate action to reduce the release of carbon dioxide. The report says governments around the world already have the ability to slow or stop this pollution. It says policy makers should support increased use of natural gas and less dependence on coal for fuel. The report supports increased use of wind power and other kinds of renewable energy.

The report suggests other ways to reduce carbon dioxide emissions. They include developing vehicles that use less fuel and speeding the use of energy efficient lighting.

The report says governments must provide support for such changes. This will help industries develop new technologies and improve present methods of energy use.

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The report says actions being taken today are not enough to stop the expected damage. It says carbon dioxide emissions must start to fall within the next fifteen years. Without additional action, the amount of heat-trapping gasses released by the year twenty thirty would grow by up to ninety percent.

The report sets a goal of limiting the average temperature change worldwide to two degrees Celsius by twenty fifty. That would require a gas emissions cut of more than fifty percent of emissions levels in the year two thousand. The report says this will not be costly. It says this can be done at a cost of less than three percent of the world's gross domestic product by twenty thirty. Gross domestic product is the value of all goods and services produced by any one country.

Last week, President Bush announced his own plan to fight climate change. He wants fifteen major polluting countries to set a goal by the end of next year to reduce gases tied to climate change.

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In the West Bank, a thirty-year long search may have finally come to an end. Israeli archeologists recently found what they believe to be the burial place of King Herod.

The Roman Empire appointed Herod as the ruler of Judea over two thousand years ago. The Christian Bible's book of Matthew says King Herod ordered the killing of all boys two years old or younger in the Bethlehem area. Historical experts do not know if this story is true. But they do know that Herod killed many of his political opponents by the end of his rule.

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Archeologist Ehud Netzer works at Hebrew University in Israel. He led the team of researchers who discovered the burial place at Herodium. Herodium is a large area with many buildings and other structures. It is built on a small man-made mountain about eleven kilometers south of Jerusalem.

King Herod built Herodium and its many richly designed buildings as an example of his power and wealth. He also chose the exact place where he wanted to be buried. But it has taken a great deal of searching for the team of researchers to find the area. They had been searching for years at the bottom of the small mountain of Herodium. In August, they moved their dig higher up the side of the mountain.

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Knowledge of King Herod's burial comes from the first century historian Josephus Flavius. He described how Herod's body was carried to Herodium and gave details about his funeral. Flavius wrote about Herod's rich burial coverings that included solid gold objects, jewels, and purple colored cloth. But the historian did not say where the body was buried.

The archeologists recovered many broken pieces of a sarcophagus -- a container used to hold a buried body. The container was made out of limestone and measures about two and a half meters long. Other broken pieces near the sarcophagus include stone cuttings made to look like flowers. The costliness of the objects led the researchers to believe that this must be King Herod's burial place.

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Other experts say there is still no evidence confirming the burial place belongs to Herod. Stephen Pfann is a historian at the University of the Holy Land in Jerusalem. He says Ehud Netzer and his team have made a valuable discovery. But he says there is no way to be sure the place was King Herod's until someone finds his name among the burial objects.

The discovery has increased old political tensions between Israelis and Palestinians. Both sides claim this area between Bethlehem and the Judean desert.

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Scientists may have found a way to reduce shortages of type O blood. Type O is the kind of blood that hospitals most often need. What the researchers are testing is an easier way to make type O blood out of other kinds of blood.

There are four main kinds of blood. Most people are born with one of these four: type A, type B, type AB or type O. Type O can be safely given to anyone. So it is commonly used when a person is injured or sick and has to have blood.

Type O is the most common blood group. But the supplies of it available in hospitals and blood banks are usually limited. This is because of high demand. Type O blood is used in emergencies when there is no time to identify the patient's blood type.

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Giving A, B or AB to someone with a different blood type, including O, can cause a bad reaction by the person's defense system. Their immune system can reject the blood. This immune reaction can be deadly.

The difference between blood types is linked to whether or not red blood cells contain certain kinds of sugar molecules. These molecules are found on the surface of the cells. They are known as antigens. These antigens are found with type A, B and AB blood but not with type O.

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More than twenty-five years ago, scientists found that the antigens could be removed to create what they called universal-type cells. They could be removed with chemicals called enzymes. But large amounts of enzymes were required to make the change.

Recently, a report published in Nature Biotechnology described two formerly unknown bacterial enzymes. The report said these enzymes remove the antigens more easily. To find these enzymes, researchers examined more than two thousand five hundred kinds of bacteria and fungi.

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Doctor Henrik Clausen of the University of Copenhagen in Denmark led the study. He worked with researchers from France, Sweden and the United States.

The next step, they say, is to complete safety tests. The team is working with the American company ZymeQuest to test the new method. If it meets safety requirements and is not too costly, it could become a widely used life-saving tool to increase the supply of universal blood.

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This SCIENCE IN THE NEWS was written by Brianna Blake, Dana Demange and Nancy Steinbach. Our producer was Caty Weaver. I'm Bob Doughty.

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And I'm Faith Lapidus. Listen again next week at this same time for more news about science in Special English on the voice of America.