Although Greenland is at the same latitude as parts of Northern
Canada, Greenland is largely covered by a massive ice sheet:
"90 percent of Earth's ice mass is in Antarctica, while the
Greenland ice cap contains 10 percent of the total global ice
mass ... The ice cap averages about 5,000 feet (1,500 meters)
"Water Storage in Ice and Snow"
This is largely due to the cooling effect of the East Greenland
Current, which flows south along the east coast of Greenland:
"the East Greenland Current transports ... over 90% of the ice
exported from the Arctic Ocean ... carries sea ice and polar
water out of the Arctic Ocean"
"The East Greenland Current"
You can view an animated image showing ocean temperatures by clicking
the first link on the following page. You will see that the cold patch
near Greenland is maintained for most of the cycle:
"Ocean Planet: Ocean Currents"
Ocean currents have changed over time. During the Medieval Warm Period
(900 to 1300 AD) the vikings colonised Greenland and were able to grow
crops and raise cattle. Professor Ian Plimer explains that "in 1280
AD, volcanic eruptions on Iceland and a change in ocean currents
started the Little Ice Age":
"Greenhouse And Icehouse Over Time"
After the ocean currents changed and Greenland's climate started to
cool, the snow did not melt as fast as it was falling, and the ice
sheet started to build up. As it gained height, the colder temperature
at those higher altitudes caused the ice to build up even more.
Google Search Strategy:
greenland "covered in ice" because
greenland "covered in ice" currents
"ocean OR sea currents"