Unit 5 effective technologies in solving ecological problems

LESSON 24

1) December twenty-sixth marks the anniversary of one of the worst natural disasters in recorded history. On that date four years ago, an underwater earthquake in the Indian Ocean formed a tsunami. The earthquake and waves from the tsunami killed an estimated two hundred thirty thousand people in eleven countries.

Western Indonesia suffered most from the tsunami. The waves struck the area about fifteen minutes after the earthquake. From the coast to far inland, one hundred forty thousand unsuspecting people were killed. The event also robbed Indonesia of valuable land.

No major tsunami had been recorded in the area for hundreds of years. But new evidence shows that other such deadly events may have taken place there long ago.

Recently, a Norwegian scientist reported that a major tsunami may have struck the Indian Ocean between six hundred and seven hundred years ago. Stein Bondevik teaches at two universities in Norway. Two teams provided the information he presented. His report and their studies all appeared in the publication Nature.

A team in Thailand reported finding evidence of a tsunami striking that country a few centuries ago. Kruawun Jankaew works at Chulalongkorn University. Her team found sand material that represents a tsunami from six hundred to seven hundred years ago.

The other team was led by Katrin Monecke of Kent State University in the United States. Her team unearthed evidence in the Indonesian island of Sumatra. Team members found sand material from the tsunami in two thousand four. They also found evidence of three tsunamis from the past one thousand two hundred years. One of these may be the same event that hit Thailand six to seven centuries ago.

2) A new study says almost forty percent of China is losing soil because of wind and water erosion. The Chinese government recently announced the results of a three-year study. The study was the largest of its kind since China became a communist nation in nineteen forty-nine.

Researchers found that China has three and one-half million square kilometers of eroded land. Water has eroded more than one and one-half million square kilometers of that territory. Wind has damaged almost two million square kilometers.

The researchers blamed farming and the clearing of forests for much of the damage. Rural areas are not the only ones losing soil. Land is also being affected in cities and near mines and factories.

The researchers say that every year, four and one-half billion tons of soil are washed or blown away. At that rate, they say, grain production in northeastern China could decrease forty percent within forty to fifty years. The country depends on that area for grain; the northeast is often called China's breadbasket.

The research team estimates that erosion has cost China at least twenty-nine billion dollars in economic losses since two thousand. The team also says that seventy percent of China's poor live in areas damaged by soil loss.

Xinhua, the official news agency, reported that the team said China is in a worse situation than many other countries suffering from soil erosion. These include India, Japan, the United States and Australia.

Land sometimes becomes desert and can no longer support plants. This process is called desertification. A study published earlier this year suggested that climate change has been a major cause of this in China. The paper appeared in Earth-Science Reviews in June.

Scientists say more than ninety percent of grasslands in northern China have decreased in quality as a result of desertification. Dried lakes in the north produce most of the dust that affects life for people in cities like Beijing and Tianjin.

Still another problem for China has been flooding along the Yangtze River. Widespread flooding took place in the late nineteen nineties. After that, the government limited tree cutting along the sides of mountains near the river.

And that’s the VOA Special English Agriculture Report, written by Jerilyn Watson. Archives of our reports are at voaspecialenglish.com. I’m Jim Tedder.

Дата добавления: 2015-11-16