Melting Poles

North Pole Melting

If last summer's record melting trend continues, the ice that usually floats on the surface of the Arctic Sea year-round may be gone by September. More than 70% of the current Arctic sea ice is less than a year old and only 60 inches deep. Mark Serreze, a senior researcher at the National Snow and Ice Data Center at the University of Colorado, said there's a 50% chance that ice at the North Pole will melt completely this summer.

Planet Needs Polar Ice

Losing year-round polar ice could heat the planet faster than expected.

The Arctic ice pack helps cool the Earth in several ways:

• The ice's reflective surface bounces the sun's rays back out of the atmosphere. Known as "albedo," this reflective property prevents rays from heating the ocean.
• More ice keeps the ocean from absorbing heat.

Without the ice pack, the Earth's temperatures could rise:

• Less ice means the ocean absorbs more heat, causing sea ice to melt even faster.
• A rise in ocean temperatures may accelerate global warming.

"On any given day, sea ice cover in the oceans of the polar regions is about the size of the U.S.," said Thorsten Markus, a research scientist at NASA's Goddard Space Flight Center. "Far-flung locations like the Arctic and Antarctic actually impact our temperature and climate where we live and work on a daily basis." (Science Daily, 6/30/2005)

Ice in Antarctic Increases

Although Arctic sea ice is rapidly diminishing, the amount of sea ice worldwide hasn't changed much. This is because the sea ice sheath that forms around the Antarctic each year is growing.

Dylan C. Powell, co-author of a 2005 NASA-funded study, said that the increase in Antarctic sea ice is consistent with the study's projections.

"Findings from our simulations suggest a counterintuitive phenomenon," Powell said. "Some of the melt in the Arctic may be offset by increases in sea ice volume in the Antarctic." (Science Daily, 6/30/2005)

The Antarctic ice is expanding because the seasons at the South Pole are opposite to those at the North Pole. Melting sea ice in the north means there's more moisture in the atmosphere. This causes more precipitation worldwide. So more snow falls in the Antarctic where it is winter, forming greater quantities and thicker ice.

This increase of ocean ice in the Antarctic helps keep ocean levels constant, but may have as-yet-unknown consequences for the global climate.

Pole Ice Melt Depends on Weather

Though there is a good chance that the Arctic ice will melt by the end of the summer, it's not a certainty.

"It will probably come down to how cloudy it is this summer," Mahoney said, "If there's clear skies and if atmospheric patterns resemble last year's, you're going to see a lot more melt." (ABC News, 6/30/08)

Melting Arctic Ice Opens Northwest Passage

Melting Arctic sea ice isn't bad for everyone, though. For centuries, explorers looked for a shorter route between Europe and Asia, across the top of the world, but were thwarted by the year-round ice on the Arctic sea.

Last September, the legendary "Northwest Passage"—an open waterway from Greenland to Alaska—was navigable for the first time.

Andy Mahoney, a researcher at the University of Colorado's National Snow and Ice Data Center said, "If the North Pole melted out, the shipping industry would be paying very close attention." (ABC news, 6/30/08)