Why is Arctic ice melting 50 years too fast?

by Jacob Silverman

Inside This Article
1. Why is Arctic ice melting 50 years too fast?
2. Consequences of Melting Arctic Ice
3. Lots More Information
4. See all Geophysics articles

On Aug. 19, 2007, a joint survey by the Japan Agency for Marine-Earth Science and Technology and the Japan Aerospace Exploration Agency revealed that Arctic ice was melting at a far quicker rate than anticipated. What's particularly alarming about this discovery is that the United Nations' scientific models anticipated that the ice levels measured by the Japanese team would not be reached until after 2040 -- and possibly not until 2050.

Image courtesy National Snow and Ice Data Center This satellite image shows that Arctic ice levels in 2007 (left) were less than even the record low levels of 2005 (right). See more global warming images.

A researcher at the Colorado Center for Astrodynamics said that Arctic ice is melting at previously unseen rates [source: Science Daily]. The melting has caused coastal ice in parts of Canada and Alaska to become quite brittle. That ice easily breaks away in large chunks (a process known as calving) and melts in the open ocean. There's also less sea ice in the Arctic Ocean because ice has floated into the Atlantic Ocean. The previous record low for Arctic sea ice was recorded on Aug. 15, 2005, though scientists said there was a high probability that the record would be breached in 2007.

The Arctic saw another milestone in the summer of 2007. In August, the Northwest Passage had almost no floating ice. It was the first time the Passage had been completely open to shipping since people started keeping records in 1972. Scientists say that the lack of ice represents clear proof that the planet is warming. The now-open sea lane means that someone could sail from New York to Korea without encountering any ice, though bad weather is always possible. In comparison, the first explorer to navigate the Northwest Passage successfully, Roald Amundsen, took three years to get through the waterway's thick ice.

Sea ice is measured primarily through three methods: microwave scanners on orbiting satellites, buoys and observation platforms. The latter two are generally equipped with several types of measuring devices. Scientists focus their measurements on the extent of sea ice, rather than the thickness, since it's easier for satellites to measure extent. When examining sea ice, scientists look at the minimum and maximum extent, thickness, environmental conditions and changes in the melting season. The Arctic sea ice melting season usually lasts from March to the middle of September.

This record pace of Arctic ice melt has scientists concerned about rising sea levels, diminished habitats for polar bears and other animals and an impending rush for fossil fuels in the region. Increased traffic through the Northwest Passage and the Northeast Passage (which runs by Siberia) may increase pollution in the area.

Ice re-forms during winter, but due to warmer waters the amount of re-formed ice appears to be decreasing. Ice that was previously considered "permanent" is now melting. That leaves an ever-decreasing base of ice at the beginning of each melting season.

Sea ice plays an important role in keeping temperatures down around the world. Whereas sea ice reflects 80 percent of sunlight back into the atmosphere, ocean water absorbs 90 percent of sunlight [source: National Snow and Ice Data Center]. As melting ice exposes more ocean to direct sunlight, scientists expect water temperatures to rise, accelerating the ice melt.

Consequences of Melting Arctic Ice
The opening of the Northwest Passage and melting of Arctic ice has allowed access to parts of the Arctic Ocean and the seabed that have been blocked for centuries. Consequently, several countries are trying to lay claim to parts of the newly opened Arctic in hopes of getting at some of the oil and natural gas reserves that are buried under the ocean floor. Experts estimate that 25 percent of the world's remaining fossil fuel reserves lies under the Arctic seabed [source: Guardian Unlimited]. Commentator Jeremy Rifkin noted with irony that it's the burning of fossil fuels and the subsequent rise of global temperatures that has made it possible to access these long-blocked stores of oil and gas [source: Houston Chronicle].

The 1982 Law of the Sea Treaty gives countries an economic zone extending 200 miles from their coasts, and it's under the provisions of this treaty that some countries are trying to lay claim to parts of the Arctic. In August 2007, Russia planted a flag on the Arctic seabed, following a claim that part of the ocean floor is an extension of their country's continental shelf. Canada, Norway and Denmark (via Greenland) are making similar claims. The United States and Canada still dispute who has the right to claim the Northwest Passage while both Denmark and Canada claim sovereignty over Hans Island.

Some commentators say that a new oil rush is underway that will further imperil the region's delicate environment. Despite the controversy, Russia and Canada, in particular, appear to be aggressively pursuing their claims in the region. Russia is expanding its drilling operations in the waters off Siberia. Canada is spending several billion dollars to add a deep-water seaport and new patrol ships to their Arctic territory. Canada's Prime Minister, Stephen Harper, said that "Canada's position is that we intend our position in the Arctic area" [source: CanWest News Service].

Scientists call this rush for fossil fuels and the melting of permafrost in Siberia and other areas a "ticking time bomb" [source: Houston Chronicle]. If Siberia's vast permafrost continues to melt, massive amounts of methane, now trapped beneath the ice, may be released. Methane is a highly potent greenhouse gas, more than 20 times stronger than carbon dioxide. Scientists fear that the release of so much methane may initiate a sort of feedback loop, wherein methane release increases the rate of global warming, in turn spurring more permafrost melt and more methane release [source: Houston Chronicle].

One of the more visible effects of Arctic ice melt is the calving of large pieces of ice from glaciers and ice shelves. In 2005, the Ayles Ice Island, a 30-square mile chunk of ice, broke away from Canada's Ayles Ice Shelf and began drifting through the Arctic. Some people worried that the ice island would crash into Alaskan oil rigs in the Beaufort Sea, but as of late August 2007, it was stuck in a channel in the Canadian High Arctic, 300 miles from its original location.