Landfills are places where a large amount of waste and other refuse is buried in the ground. They are responsible for releasing a large amount of planet-warming methane gas into the atmosphere, a new study suggests.
The study, which was published in Science Advances on Wednesday, is aimed at helping local governments carry out targeted efforts to limit global warming by identifying areas of major concern. For this purpose, the scientists used satellite data from four major cities around the world — Delhi and Mumbai in India, Lahore in Pakistan and Buenos Aires in Argentina.
Based on the collected data, the scientists have drawn the conclusion that landfills are the third-largest source of methane emissions (排放) worldwide, after oil and gas systems and agriculture. And further investigation shows that the methane released from the landfills is generated from the decomposition (分解) of natural waste in them, like food, wood or paper.
Methane, though only accounting for about 11 percent of greenhouse gas emissions, traps 80 times more heat in the atmosphere than CO₂. Scientists estimate that at least 25 percent of today’s warming is driven by methane from human actions. That’s why landfills are partly to blame for the global warming.
Joannes Maasakkers, a leader of the study, said, “We found that these landfills, which are relatively small compared to city sizes, are responsible for a large part of total emissions from a given area.” Another scientist, Euan Nisbet, who was not part of the study, said, “This new work shows just how important it is to manage landfills better, especially in countries like India where landfills are often on fire, resulting in a wide range of damaging pollutants (污染物).” He also added that the newer satellite technology and on-the-ground research make it easier for researchers to identify “who is polluting the world”.
【小题1】Why did the scientists carry out the study?| A．To reduce the emission of the methane. | B．To help the authorities control the global warming. |
| C．To test out the new satellite technology. | D．To clarify which places people are concerned about. |
| A．There exists methane in food, wood and paper. |
| B．Methane makes up most of the greenhouse gases. |
| C．More methane is released from landfills than from agriculture. |
| D．Methane prevents more heat in the air from escaping than CO₂ does. |
| A．Favourable | B．Concerned | C．Unclear | D．Doubtful |
| A．Methane causes the temperature of the earth to go up. |
| B．Satellite data help identify the source of the pollutants. |
| C．Landfills are to blame for the release of much methane. |
| D．Waste and other refuse should be forbidden for their impact. |
