发布时间：2020-06-19 20:03:22 来源：听力鸭英语网
More than a century of oil and gas drilling has left behind millions of unused wells, many of which release pollutants into the air and water.
Drilling companies are likely to leave behind many more abandoned wells since they are losing money, as oil prices struggle to recover from historic lows, experts say. They note that the coronavirus health crisis crushed international demand for fuel.
Leaks from abandoned wells have long been recognized as an environmental problem and a risk to public health. Studies have linked abandoned wells to groundwater pollution in the United States. They also have been blamed for a large number of public safety incidents over the years.
Abandoned wells are also a serious threat to Earth's climate that researchers and government officials are only starting to understand. That finding comes from a Reuters news agency review of government records and statements by scientists, government experts and United Nations officials.
The Intergovernmental Panel on Climate Change offered a proposal to U.N. member countries last year. It urged them to start studying and publishing information about the amount of methane released from abandoned oil and gas wells.
Currently, Canada and the United States are the only countries to do so. In the U.S., more than 3 million abandoned oil and gas wells together released some 281 kilotons of methane in 2010. Those numbers come from the Environmental Protection Agency's most recent report to the U.N. Framework Convention on Climate Change.
The Environmental Protection Agency, or EPA report noted that the amount of methane emitted is almost equal to the burning of 16.2 million barrels of crude oil.
The true amount, the EPA said, may be 3 times higher because of incomplete data.
The problem is less serious in Canada, where most oil production comes from oil sands mining instead of traditional drilling operations. The Canadian government believes the country's 313,000 abandoned wells released about 10.1 kilotons of methane in 2018, far less than the United States.
The effect of abandoned wells on the health of our planet is more difficult to study. The governments of Russia, Saudi Arabia and China – the world's other top oil and gas producers – did not respond to Reuters' requests for comments.
Researchers note that it is impossible to say the total amount of emissions worldwide without better records. But an estimate by Reuters, based on the U.S. numbers for oil and gas production, would place the total number of abandoned wells at around 29 million. That number of wells could release as much as 2.5 million tons of methane per year.
I'm John Russell.
The Reuters news agency reported this story. John Russell wrote the story for VOA Learning English. George Grow was the editor.
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drill – v. to make a hole in something with a drill or power tool
review – n. a study or examination of something
crude – adj. something unprocessed or in a natural state
data – n. facts or information used usually to estimate, study, or plan something
per – prep. for each