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课时知能训练Ⅰ.阅读理解 (2017·广东潮州月考)The hole in the Earth's ozone layer (臭氧层)has until now protected Antarctica 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 3℃ on average，with melting ice contributing to a global sea level increase of up to 1.4 metres. 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，paradoxically，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 Antarctica，making much of the continent surface colder than usual. But now that the gasses 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 3℃ 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 Antarctica ice sheets，said，“The ice sheets in Antarctica are hundreds of metres 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 Antarctica has already resulted in a 10% rise in global sea level in recent decades. | 
