A new report says sea ice in the Arctic Ocean is melting more quickly than expected. American scientists say the ice is melting even faster than computer programs had estimated.
Scientists know that climate change has a major effect on the Arctic Ocean partly because sea ice is disappearing. They also know that areas of open seawater are expanding. Such areas are known to take in sunlight and increase temperatures. Scientists say this has helped to cause the loss of the Arctic’s ice cover.
For the study, the American scientists compared eighteen computer programs with observations made by satellites and other instruments. The Intergovernmental Panel on Climate Change used the computer programs to prepare its 2007 estimates of climate change.
The computer programs gave estimates of the amount of ice in the Arctic Ocean in the month of September. September is when the Arctic has the least ice, after the warm, summer months. The computer estimates suggested an ice loss of two and a half percent for every ten-year period between 1953 and 2006.  
Newer studies of the Arctic have used information gathered by aircraft, satellites and ships. This information showed a loss of September ice cover of almost eight percent for every ten-year period between 1953 and last year. This means the ice is disappearing about thirty years faster than the computer programs estimated.
The scientists say the programs might not have recognized the full effect of increased carbon dioxide and other gases in Earth’s atmosphere. They say their study suggests the gases may have more of an effect than had been thought.
It is reported that sea ice in the Arctic Ocean is melting more quickly than expected mainly because _________.

A．climate change	B．sea ice’s disappearance
C．seawater’s expansion	D．the loss of the Arctic’s ice cover

How did the scientists draw the conclusion that sea ice in the Arctic Ocean is melting more quickly than expected?

A．The scientists have been observing the Arctic Ocean for many years.

B．The scientists have compared the computer programs with observation made by satellites and other instruments.

C．The scientists have figured out many numbers with the help of computer.

D．The scientists have found that the seawater take in sunlight and increase temperatures.

If the ice melts at the present speed, by the end of this century the ice loss in the Arctic Ocean will be _________ according to newer studies.

A．22.5%

B．35%

C．72%

D．100%

Which of the following is TRUE according to the passage?

A．The figures of the computer estimates are wrong.

B．Scientists study climate change through studying sea level.

C．Newer studies show gases may have more effect on sea ice in the Arctic Ocean.

D．The ice is melting even faster than satellites have estimated.

This report mainly warns human to _________.

A．prevent the sea ice in the Arctic Ocean from melting any more

B．pay more attention to the loss of the Arctic’s ice cover

C．take necessary steps to protect the environment of our earth

D．stop summer sea ice in the Arctic from disappearing so fast