Homo Floresiensis / Arctic Warning / Polio Vaccination Days in Africa
This is SCIENCE IN THE NEWS, in VOA Special English. I'm Barbara Klein. And I'm Bob Doughty. On our program this week: a new effort against the disease polio and an ancient group of little people.
But first, rising temperatures in the northernmost part of our planet.
A new report says the Arctic is experiencing some of the most severe climate change on Earth. The report says average winter temperatures there have risen at almost two times the rate of that in other areas in the past fifty years. It also says computer programs estimate an additional increase of four to seven degrees Celsius during the next century.
About three-hundred scientists prepared the report after a four-year study. The scientists say human activities are responsible for increasing amounts of heat-trapping gases in Earth's atmosphere. Other studies have linked recent climate changes to such activities.
The report was presented to an organization called the Arctic Council. Its members include the United States and the seven other countries with territory in the Arctic. Six groups representing native peoples also are members. The Council considered the report last week during a meeting in Reykjavik, Iceland.
Robert Correll of the American Meteorological Society led the committee that wrote the report. He says climate changes will have a major effect on the Arctic. Polar bears and some kinds of seals may disappear. As a result, native peoples who hunt for these animals will experience food shortages and economic problems.
The report also warns of possible health risks to people. As new kinds of wildlife move into the Arctic, animal diseases that can infect people may spread. And, northern freshwater fisheries that supply the native people with food could suffer.
The report says melting ice would add more freshwater to the Arctic Ocean. This could cause sea levels to rise around the world. As the frozen ground warms, many existing buildings in the Arctic, roads and industrial areas could be damaged.
The report notes some possible improvements as a result of rising temperatures. For example, the melting ice will increase the ability of fish and other sea creatures to use Arctic resources. The melting is likely to permit increased exploration for oil and gas. And, reduced ice is likely to extend the period when ships can travel in the area.
This week, health workers in West and Central Africa are starting a new effort against the disease polio. The effort is aimed at young boys and girls in more than twenty countries. The workers plan to give polio vaccines to the children. Vaccines help the body's natural defense system recognize and fight disease.
Last month, one million people spread out over twenty-five African countries to vaccinate boys and girls against polio. The goal of the effort is to protect eighty-million children against the disease. Organizers called it the single largest public health campaign in history.
A virus causes polio. The virus is spread through body fluids and also water or food touched by an infected person. People who get the disease often lose their ability to move their arms or legs. Some die from polio. There is no cure.
However, polio can be prevented. To work best, the vaccine is given to children several times during the first years of life. World health officials have set a goal of defeating polio by two-thousand-five.
Polio began to spread in Africa last year after Islamic religious leaders in northern Nigeria said the vaccine was harmful. Kano State and other areas halted an effort to vaccinate children. Since then, polio has spread to four countries where it had been completely removed. Now the leaders in Kano State say there is a safe vaccine. They supported the vaccination campaign in October. Yet there were protests in other parts of Nigeria.
Leaders across Africa have been organizing support for the vaccination campaign. Last month, religious and traditional leaders from several African countries met in Dakar, Senegal. They agreed to use their organizations and influence to support vaccination efforts and other programs to keep children healthy.
Esseldin El Sawy of Al-Azhar University in Egypt attended the Senegal meeting. Doctor El Sawy noted that the average vaccination rate in Muslim communities in Africa is lower than the rate worldwide. He says Islam supports the protection of every human being, including children.
Debate continues about the remains of small human-like creatures discovered in Indonesia. A team of Australian and Indonesian scientists reported the discovery last month in Nature magazine.
The first of the bones were uncovered last year in Liang Bua, a large cave on the island of Flores. The scientists believe the bones came from an adult who stood only about one meter tall. Their study found that such individuals lived as recently as twelve-thousand years ago.
The scientists also say the bones appear to be different from those of any known group, or species. So, they consider these human-like creatures to be part of a new species. The scientists have named it Homo floresiensis, or man of Flores.
The bones of several other human-like individuals have been found in Liang Bua. At first, the scientists thought the remains came from children. But, closer study of the teeth and bones confirmed that they belonged to adults.
The discovery has caused excitement in the field of archaeology, the study of material remains of past human life and activities. This is partly because the bones represent a new species. But, scientists are even more interested in learning how Flores Man developed.
The scientists described the remains of an individual believed to have been a woman. Tests showed the woman was about thirty years old when she died about eighteen-thousand years ago. Her brain was only about one-third the size of a human brain.
The scientists also discovered what they believe are stone tools near the bones. They say there are signs that Flores Man knew how to use fire and hunted as part of a group. This suggests a higher level of mental development than thought possible for a small brain. Human development theories are based in part on the idea that as the size of the brain grew, so did intelligence.
The scientists also found the remains of an ancient species of elephant called a Stegodon. Unlike modern elephants, Stegodons were about the size of the human-like beings. The remains of large meat-eating lizards also were uncovered. These creatures were similar to reptiles still living today on the nearby island of Komodo. They are called Komodo Dragons.
Australian archaeologist Mike Morwood directed the dig on Flores. He believes that Flores Man developed from the group of early humans called Homo erectus. That group was the same size as modern human beings. However, Homo erectus lived between two-hundred-thousand and more than one million years ago.
Mr. Morwood's earlier research has shown that Homo erectus arrived in the area more than eight-hundred thousand years ago. The bones from the recent Flores finds extend from about twelve-thousand to ninety-five thousand years ago.
Mr. Morwood argues that Homo erectus became smaller over the years in Flores as a result of the island's environment. This theory has been shown in the development of some island animals. It can happen when an animal group shares a small land area with a limited food supplies and no natural enemies.
The scientists say Flores man probably died about twelve-thousand years ago after a volcanic explosion on the island. Yet people living on Flores today still tell stories of the island's little people. They say the little people lived in caves until the first Dutch traders arrived about five-hundred years ago.
Nature magazine published a commentary by Marta Mirazon Lahr and Robert Foley of the University of Cambridge in England. They described the new findings as one of the most important discoveries in the past half-century.
This program was written by Jill Moss, Karen Leggett and Caty Weaver. Cynthia Kirk was our producer. And, our engineer was Dwayne Collins. I'm Barbara Klein. And I'm Bob Doughty. We would like to hear from you. Write to us at Special English, Voice of America, Washington, D.C., two-zero-two-thirty-seven, U.S.A. Or send electronic messages to email@example.com. Join us again next week for Science in the News in VOA Special English.