polar glacier वाक्य

Global warming affects the sea level in two ways : the melting of polar glaciers adds to the amount of water in the sea, and as the atmosphere warms the temperature of the water rises, causing the volume of the earth's water to expand.
The Heinrich event 4 ( H4 ), the name given to a cooling period, characterized by a break off of unusual large sections of ice from polar glaciers occurred around 40, 000 years ago being well documented in the North Atlantic Ocean, although its impact on terrestrial areas is a matter of ongoing debate.