The weather was windy and overcast the morning I set out for the Cold Regions Research and Engineering Laboratory (CRREL), located a little over a mile north of campus. I was interviewing for a Women In Science Project (WISP) internship entitled “Arctic Sea Ice Cover in a Changing Environment.” I was first interested in the role of the Arctic in a changing environment, and second, the lack of synergy between the scientists studying climate change and the public policymakers attempting to address the issue. That first meeting with Don Perovich, the scientist sponsoring the internship, turned into less of an interview and more of a discussion on the state  of the world; the apathetic, individualistic, short-term attitude of many toward the environment; and the implications of climate change.

The sun was shining when I left CRREL. I was excited and inspired by three central questions that came up during our conversation: How can we tell that the Arctic is warming? Are these changes a climatic trend or a fluctuation? And are these changes caused by anthropogenic (human) actions? These questions were reiterated by Dr. Jackie Richter-Menge, a colleague of Perovich’s at CRREL during her recent talk at Dartmouth, entitled “A Polar Bear’s View of Climate Change.” After months of reading, researching, and staring at satellite pictures of the Arctic sea-ice cover, I have come to the same conclusion that Mabel Toolie, a native Inuit, had come to after weather patterns became impossible to predict using traditional methods of observation: “The Earth is faster now.”

Why study global warming in the Arctic? Although most Arctic scientists enjoy their work, for most people, spending up to ten hours a day unsheltered from negative-40-degree-Fahrenheit temperatures and blistering winds on a boat frozen into the sea-ice is not an appealing career choice. The vital importance of the poles in discussions of climate change is due to their control over the Earth’s heat balance. Since most incoming solar energy is absorbed in the tropics, circulations of water and wind carry and distribute the heat in the northern hemisphere from the southern to the northern latitudes. Upon reaching the Arctic, the snow and ice cover will typically act as a heat sink, cooling the water and reflecting additional solar energy so that the water will eventually sink and flow back towards the equator. Recent changes in the Arctic climate system—shrinking glaciers, melting sea ice, thawing permafrost, and a changing growing season and vegetation patterns—are all symptoms and causes of global climate change.

How can one tell the Arctic is warming? The Arctic is unique as a system because it is composed of a number of regional climates: from the boreal forests of Canada to the Siberian tundra, with unique biotic (living) and abiotic (nonliving) components. As a whole, the Arctic can be characterized by a lack of sunlight during the winter months with almost constant sunlight during the summer months. The cryosphere—snow, ice sheets, glaciers, sea ice, and permafrostis the prominent terrestrial feature of the Arctic region, while the marine environment is stratified into snow, sea ice, surface water, warm and cold intrusions from ice-free seas, and deep water. All of these climatic features interact with the global climate system and southern latitudes through the atmosphere, ocean, and river systems.

Warming in the Arctic is evident in a number of changes taking place in these ecosystems. On land, glaciers have been shrinking at an increasing rate for the past several decades. In Alaska, as reported in a study conducted by Don Perovich, Matthew Sturm, and Mark Serreze, the rate of glacial melt has tripled in the last ten years, contributing to a two millimeter rise in sea level, or 10 percent of the total annual rise of 20 millimeters. The Greenland Ice Sheet has also been experiencing overall melting, setting a summer record in 2002 that the winter snowfall was unable to replace. According to glaciologist Eric Rignot of the Jet Propulsion Laboratory and University of Kansas professor Pannir Kanagaratnam, the Greenland Ice Sheet is melting at twice the rate it was in 1996, a rise from 22 cubic miles of water flowing into the oceans to 53 cubic miles. To put this in perspective, one cubic mile of water is five times the amount of water Los Angeles uses in a year.

The thawing of Arctic permafrost—the permanently frozen layer of soil beneath the surface layer—causes infrastructure damage to buildings, roads, and pipelines as the solid foundations that these structures were built upon turn to liquid. Images of collapsed buildings, exposed pipeline, and flat roads twisted into ribbons aren’t unusual. Melting permafrost has also contributed to the discharge of underground freshwater into the oceans—Russian rivers are dumping an extra seven percent of freshwater into the Arctic basin. This increase is disturbing because the Arctic basin has a certain threshold of fresh water that it can withstand before it dilutes the water’s salt content to the point where global circulation patterns are altered. This phenomenon was popularized in the movie “The Day After Tomorrow,” where the slowing down of the Gulf Stream resulted in an Ice Age in the Northern Hemisphere.

Further terrestrial evidence of global warming in the Arctic can be seen in the migration of plants further northward. Additionally, the growing season now extends about a week or two later into the fall, with the first bloom occurring several weeks earlier in the spring.

Typically, the Arctic acts as a sink for carbon, storing it as frozen peat across Alaska and Russia. However, as the climate warms, the Arctic could become a net source of greenhouse gases, releasing its carbon and methane stores into the atmosphere.

The most visually striking climatic trend observed in the Arctic, however, is the reduction in sea-ice cover. Since the National Oceanic and Atmospheric Administration (NOAA) began monitoring the Arctic sea-ice cover in 1972, they have detected an approximate three percent decrease in sea-ice extent each decade. Since the Arctic sea-ice cover is roughly the same size as the United States, this reduction translates into losing a combination of the Colorado and New Hampshire landmasses each decade. During this same period, Arctic sea-ice thickness has undergone a dramatic 40 percent reduction.

Melting sea ice does not contribute to rising sea levels since it displaces water as it floats. However, the loss of sea ice does adversely affect the wildlife and indigenous peoples relying on it for shelter, food, and transportation. The primary climatic concern of reduced sea-ice cover, which is Don Perovich’s main area of research, has to do with its ability to reflect incoming solar radiation, a process called the ice-albedo feedback loop.

Albedo is the measure of the reflectivity of a surface. A surface with an albedo of 1.0 reflects all light, while a surface with an albedo of 0 reflects none. It’s affected by the color of a surface, its texture, slope, and degree, as well as the angle of the incoming light. The Arctic Ocean is unique in that the sea-ice and snow have an albedo of 0.85, the highest of any natural surface on Earth while water has an albedo of only 0.07, the lowest of any natural surface As sea-ice and snow melt, the darker ocean is exposed, absorbing more heat and causing more melting.

This is a positive feedback loop, meaning that the more exposed liquid ocean, the more melting will occur. The ice-albedo loop operates in concert with other feedback mechanisms, making the future state of sea-ice difficult to predict. For example, a warmer climate caused by a lower albedo means the atmosphere can hold more water vapor, which produces more clouds. More cloud cover shields the surface of the Earth and reduces the amount of sunlight coming through, resulting in cooling. At the same time, however, cloud cover prevents long-wave radiation reflecting off the Earth from escaping, resulting in warming.

Yet another concern regarding the loss of sea-ice deals with the opening of new shipping and transportation routes, which creates the possibility for political conflict over the territorial sovereignty of the open ocean and transboundary pollution from shipping, fishing, and tourist vessels.

While the Earth has undergone climate fluctuations before, Arctic data from the past decade that illustrate the melting of glaciers, inflow of freshwater into the Arctic basin, shifting vegetation, and reduction in sea-ice extent and thickness all show not just a gradual trend, but an acceleration in warming that has never before occurred in such a short period of time.

Changes in the Arctic climate have already had repercussions outside of the polar region. Glacial melt’s contribution to sea level rise has been threatening the shorelines of coastal areas. Indeed, in places such as Tuvalu, coastal erosion has already taken its toll and threatens to do even more damage. Tuvalu is the world’s fourth smallest country, consisting of nine islands in the southwest Pacific where the highest point reaches only four meters. A surge in the number of waves exceeding this height, as well as the increased intensity of tropical storms, has resulted in severe erosion and damaged plants, crops, and homes. It is predicted that the entire island chain will be underwater within the next 50 years, requiring the relocation of Tuvalu’s over 11,000 inhabitants.

After more than four months of working with Don Perovich and other scientists at CRREL, I have come to the conclusion that yes, the Arctic is warming, that it is not just a fluctuation, but a climatic trend, and that human practices are undoubtedly a direct cause. 2005 set the record as one of the hottest years in over a century and there are no signs that we should expect a reversal anytime soon. As TIME magazine states in its recent special report on global warming, we should all “Be worried. Be Very Worried.”