Climate Facts 100 yr global temp. rise 0.6°C 20 yr decr. in Arctic Ice extent 2.9% Avg. 30 yr warming of Arctic Region 1.5°C 20 yr incr. in Arctic Melt Season 8% or 10 days Major Research Studies Barents and Bering Sea Impacts Studies (BASIS & BESIS) Did you know? Within the past 750,000 years, scientists know that there have been eight Ice Age cycles, separated by warmer periods called interglacial periods. A relatively intense warming of more than 1.5° Celsius has occurred over the past thirty years over much of the landmasses of Siberia, Alaska and Western Canada. Average sea level pressure has dropped over the central Arctic Ocean and there has been an increase in high latitude storms. Scientists believe that a lengthening melt season is at least partially to blame for the more frequent occurrence of large areas of open water, called "leads" in Arctic sea ice, and for an overall thinning of the ice pack. Less ice and warmer air would allow more moisture to evaporate from the water, which might make the Arctic cloudier. This would probably change regional weather patterns, but no one really knows how it would influence climate on a larger scale.

Arctic Climatology

These are some of the questions facing Arctic climatologists today. Predicting the effects of global climate change on Arctic temperatures and precipitation patterns has proven to be a very difficult task indeed. However, systematic observations of Arctic sea ice and longer term temperature records from ice cores, tree rings, and lake bed pollen samples suggest that the Arctic land area is now warmer than it has been in at least 400 years. What's more, most computer models of the atmosphere project that greenhouse warming will affect the Arctic more than any other part of the planet as melting snow and ice result in more areas of darker tundra and open ocean surfaces, meaning less reflected sunlight and an accelerated warming trend.

Long term climate records suggest that most of this warming, especially after 1920, is driven by increasing levels of human-created greenhouse gases in the atmosphere. Warming Arctic landmasses; declining sea ice area, extent and thickness; decreasing salinity; and major changes in Arctic and North Atlantic air and ocean circulation all form part of the resulting picture. Climate change may already be having significant impacts, for instance, on the health and productivity of Arctic ice algae and other micro-organisms; on walrus and polar bear populations; and on the livelihoods of Arctic human inhabitants, such as the Inuit.

Arctic regions are highly sensitive to temperature change. With temperatures at or below freezing much of the year, water can easily exist in any of its three states. Ice and snow occurring close to their melting points frequently change phase from solid to liquid and back again often resulting in dramatic visual changes across the landscape. Scientists have the opportunity to monitor such phase changes by observing shrinking and growing ice and snow masses.

Sea ice decline in the Arctic has been observed in the Barents, Kara and East Siberian seas north of Russia, as well as in the Sea of Okhotsk, an icy enclave of the Pacific Ocean northwest of Japan.

Some studies have pointed to subtle changes in the Polar Front deep water circulation, which plays a fundamental role in the driving of global ocean currents. At the front near the Greenland, Iceland and Norwegian seas and the Labrador Sea, warm salty water from the North Atlantic is cooled by Arctic waters and by intense heat loss to the atmosphere; it becomes more dense and sinks to deeper layers of the ocean. In the process important nutrients are recycled and released into the water becoming the basis of the Arctic marine food chain.