Climate change could turn the Arctic Ocean into a high-speed ice superhighway. Chunks of sea ice in the Arctic are becoming thinner as old ice melts. The new ice that's replacing it travels farther and faster than the older ice had. And as the younger ice travels， it carries dirt， organisms and pollution along for the ride， new research shows.

Researchers have been tracking the movements of Arctic ice for several years. They noticed that the area covered by ice making the trek from one side of the ocean to the other has grown larger and larger. That movement means that far-flung reaches of the Arctic are becoming more connected， the speedy ice boosts the risk of speading pollution from some environmental disaster， such as oil spills.

Researchers note that "ice in the Arctic is surprisingly polluted. And when the ice travels from one part of the Arctic to the other， it carries all that material with it".

Winds sweep airborne pollution north from lower latitudes. Much of that pollution can settle into the ocean and onto sea ice. Industries along Arctic coastlines， such as gold mining， oil drilling and copper refining， also can pollute the region's waters. As new ice forms in the fall and winter， that pollution - along with nearby sand and other sediment - gets trapped inside the ice. When that ice then melts in the spring and summer， it will shed the pollution it carried back into the ocean.

Between when it forms and melts， the ice can get pushed across the Arctic by winds and ocean currents. These forces more easily shove young， thin ice along than old ice. Researchers wondered what the impact would be on these ice rafts and the pollution they held. Less ice could mean less space to carry a large load of pollutants and debris. But a less crowded Arctic might let the ice travel farther and faster.

To find out， the researchers put together snapshots of the Arctic. The pictures came from satellites far above the surface. They used computer software that can recognize the edges of sea ice. This allowed them to follow the movements of ice from formation to disintegration. To help them do that， they also included tracking buoys on the ice that had been outfitted with GPS devices.

Most Arctic ice does not go far， they found. About 60 percent of ice travels less than 100 kilometers from its birthplace. The rest covers an area equal to tens of thousands of square kilometers. It can travel hundreds or even thousands of kilometers. And the share of long-traveling ice is growing. Newton thinks the area of ice that travels a long distance over its lifetime is about 8 to 10 percent larger than it was even 15 years ago. That ice is moving faster， too. Ice now travels from Russia to Canada in four to five years or less. It took six to seven years to cover that distance only 15 years ago.

1. Which of the following is NOT the source of pollution mentioned in the article？ ____.

A. oil spill B. gold mining

C. copper refining D. deep sea fishing

2. To find out how far and fast the ice travels， researchers used ____.

a. snapshots of the Arctic

b. computer software

c. tracking buoys outfitted with GPS devices

d. drillers

A. bcd B. abc C. acd D. abcd

3. What does “shed” mean in Paragraph 4？ ____.

A. drop B. absorb C. shelter D. soak