The North Pole and the South Pole are the coldest places in Earth. However, as similar as these areas may seem, one is much more icy than the other.
So which pole is the coldest?
The North Pole and South Pole are cold because their positions at the top and bottom of the planet mean they do no direct light (opens in a new tab) of the sun. At both places, the Sun still rests low on the horizon, even in the midst of their summers. During their wintersthe sun is so far below the horizon that it does not rise for months at a time.
In addition, the white surfaces of ice and snow at the poles are highly reflective. This means that most of the energy from sunlight that reaches them bounces back out into space, keeping the air above these surfaces relatively cool.
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While these factors make both poles downright cold, the South Pole remains noticeably colder than the North Pole, according to the Woods Hole Oceanographic Institute (opens in a new tab). The average annual temperature at the North Pole is minus 40 degrees Fahrenheit (minus 40 degrees Celsius) in winter and 32 F (0 C) in summer. In contrast, the South Pole averages are much colder, with an average annual temperature of minus 76 F (minus 60 C) in winter and minus 18 F (minus 28.2 C) in winter. summer.
Arctic vs Antarctica
The main reason why the South Pole is colder than the North Pole is the key difference between them. “The North Pole is an ocean and the South Pole is a continent,” Robin Bell, polar scientist at Columbia University’s Lamont-Doherty Earth Observatory in New York, told Live Science.
The Arctic is an ocean surrounded by land. Antarctica is a land surrounded by ocean. Water cools and warms more slowly than land, resulting in fewer temperature extremes. Even when the Arctic Ocean is covered in ice, the relatively warm temperature of its waters has a moderating effect on the climate, helping the Arctic to stay warmer than the Antarctic.
Moreover, while the Arctic is at sea level, Antarctic is the highest continent, with an average elevation of around 7,500 feet (2,300 meters). The higher you go, the colder it gets.
Which pole has more ice?
At the North and South Poles, ice cover varies throughout the year, growing during the long, dark winters and melting during the getting hotter are.
Most of this variation in ice cover at the North and South Poles is due to sea ice which floats, grows and melts above the ocean. Since the Arctic is almost entirely landlocked, the sea ice that forms there is not as mobile as Antarctic sea ice. As such, Arctic sea ice is more likely to converge, which generally makes Arctic sea ice thicker at around 6 to 9 feet (2 to 3 m) thick compared to Antarctic sea ice, which is about 3 to 6 feet (1 to 2 m) thick, depending on the National Snow and Ice Data Center (opens in a new tab) (NSIDC).
On average, Arctic sea ice reaches a minimum extent of about 2.5 million square miles (6.5 million square kilometers) and a maximum extent of 6 million square miles (15.6 million square kilometers), the NSIDC (opens in a new tab) said. In comparison, on average, Antarctic sea ice has a smaller minimum extent of 1.2 million square miles (3.1 million sq km) and a larger maximum extent of 7.2 million square miles (18.8 million square km).
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Yet, on average, there is no doubt that the South Pole has more total ice than the North Pole. That’s because the South Pole is home to land ice in addition to its sea ice – the Antarctic Ice Sheet is up to 3 miles (4.8 km) thick and covers around 5.3 million square miles ( 13.7 million square km), in the area of the Contiguous United States and Mexico (opens in a new tab) combined, according to national science foundation (opens in a new tab). In total, Antarctica holds around 90% of all the ice in the world.
“The volume and mass of ice on land changes little in summer as a fraction of the amount in winter because volume and mass are so large,” said Cecilia Bitz, a polar climatologist at the University of Washington in Seattle. .
Surveys of the amount of ice at the poles have revealed that the thickness and extent of summer sea ice in the Arctic have has decreased significantly over the past 30 years (opens in a new tab). This is consistent with observations of Arctic warming.
“Arctic and Greenland ice is rapidly shrinking primarily due to global warming“, Bitz told Live Science. “And shrinking Arctic sea ice tends to cause even more warming, amplifying the warming that triggers ice loss. ”
In contrast, “sea ice loss around Antarctica and glacial land ice loss over Antarctica have seen mixed changes, ups and downs, over the past 40 years when we have had reasonably good records,” Bitz noted. “The climate dynamics of Antarctica are more complicated because air and ocean circulation are very important factors there.”
Originally posted on Live Science.