The hole in the Earth's ozone layer  has until now protected Antarctic from the worst effects of global warming, but scientists have warned that as the hole closes up in the next few decades, temperatures on the continent could rise by around 3degC on average, with melting ice contributing to a global sea level increase of up to 1.4 meters. In the past decades the western Antarctic has seen rapid ice loss as the world has warmed, but the other parts of the continent have, , been cooling, resulting in a 10% increase in ice in the seas around the region. This is because the hole in the ozone layer has increased cold winds in Antarctic, making much of the continent surface colder than usual. But now that the gases that cause the ozone hole have been banned, scientists expect the hole to repair itself within the next 50 to 60 years. By then the cooling effect will have faded out and the Antarctic will face the full impact of global warming. This means an increase in average air temperatures of around 3degC and a reduction in sea ice by around a third. The biggest threat to the continent comes from warming seas. Robert Johnson, a scientist who monitors Antarctic ice sheets, said, "The ice sheets in Antarctic are hundreds of meters thick. But once warm ocean waters start flowing underneath, the ice will begin thinning and could break up very quickly." Thinning ice sheets cause ice to break away from the continent and to melt even faster. Escaping ice from western Antarctic has already resulted in a 10% rise in global sea level in recent decades. Johnson believes that international action to reduce global warming is required immediately or it may be too late. "Everything is connected----Antarctic may be a long way away but it is an important part of the Earth's system," said Johnson. "It contains 90% of the world's ice, 70% of the world's fresh water and that is enough, if it melts completely, to raise sea levels by 63 meters." Even in a worse-case situation scientists don't expect the ice to entirely disappear, but predict that, because of the melting ice sheets, average sea level rise will be around 1.4 meters higher by the end of the century. What do scientists think is the biggest danger facing Antarctic?
Rising sea levels. Warming sea water temperature. Water pollution. Growing ice sheets.
Question: The hole in the Earth's ozone layer  has until now protected Antarctic from the worst effects of global warming, but scientists have warned that as the hole closes up in the next few decades, temperatures on the continent could rise by around 3degC on average, with melting ice contributing to a global sea level increase of up to 1.4 meters. In the past decades the western Antarctic has seen rapid ice loss as the world has warmed, but the other parts of the continent have, , been cooling, resulting in a 10% increase in ice in the seas around the region. This is because the hole in the ozone layer has increased cold winds in Antarctic, making much of the continent surface colder than usual. But now that the gases that cause the ozone hole have been banned, scientists expect the hole to repair itself within the next 50 to 60 years. By then the cooling effect will have faded out and the Antarctic will face the full impact of global warming. This means an increase in average air temperatures of around 3degC and a reduction in sea ice by around a third. The biggest threat to the continent comes from warming seas. Robert Johnson, a scientist who monitors Antarctic ice sheets, said, "The ice sheets in Antarctic are hundreds of meters thick. But once warm ocean waters start flowing underneath, the ice will begin thinning and could break up very quickly." Thinning ice sheets cause ice to break away from the continent and to melt even faster. Escaping ice from western Antarctic has already resulted in a 10% rise in global sea level in recent decades. Johnson believes that international action to reduce global warming is required immediately or it may be too late. "Everything is connected----Antarctic may be a long way away but it is an important part of the Earth's system," said Johnson. "It contains 90% of the world's ice, 70% of the world's fresh water and that is enough, if it melts completely, to raise sea levels by 63 meters." Even in a worse-case situation scientists don't expect the ice to entirely disappear, but predict that, because of the melting ice sheets, average sea level rise will be around 1.4 meters higher by the end of the century. What do scientists think is the biggest danger facing Antarctic?
A. Rising sea levels.
B. Warming sea water temperature.
C. Water pollution.
D. Growing ice sheets.
Answer: