Module VIII

Essential Question:
How are Arctic sea-ice, climate and culture all connected?

The Arctic influences the climate around the world in a variety of ways. Sea ice reflect solar radiation back into space due to its high albedo. As sea ice melts it creates a positive feedback look for global warming, because the more open water, the more solar radiation is absorbed to heat the planet. This teacher domain video is a nice illustration of this positive feedback loop. Sea ice also drives thermohaline circulation in the ocean, because as it freezes it excludes salt, and this salty cold water sinks due to its high density.



Climate effects are more dramatic in the Arctic because so much there is dependent on the sea ice. Subsistence hunters, fish, birds, and marine mammals all need the sea ice to survive, and it is melting very quickly, opening up routes for boats in the northwest passage where before it was solid ice. The ecosystem in the Arctic is very productive, because it has a large base of producers: ice algae and phytoplankton. However, due to the extremes of the climate there is very low biodiversity, and small changes in the population of one species, such as polar bears, can have a dramatic effect on the entire food web. Polar bears are threatened due to increased competition with other species (grizzlies, people, etc.) and loss of their sea ice habitat. The Arctic is also vulnerable because both wind and ocean currents bring pollution away from more industrialized areas, and that pollution works its way into and up the food chain, wreaking havoc in the upper levels through bioaccumulation.

The Arctic Food Web

Recently scientists have begun to collect snow and ice data in the Arctic, and if we want older data we can look to the stories of indigenous Alaskans. These images found on the teachers domain website, show us the ice cover in the Arctic over the past 25 years. The national snow and ice data center gathers and displays field and satellite data about the cryosphere including the sea ice index and snow ground cover in the Arctic.

Arctic SSMI images from 1979 and 2003

Due to the fact that climate change and endangered Arctic species are relatively recent, the value of local native knowledge on sea ice is very high. Not many other people have spent time learning what ecosystems in the Arctic are like, and we need to know what is normal there before we can see how it is changing and guess what it will be like in the future. The Arctic ecosystem is the first to show the ravages of climate change, and it can show us the dangers that will soon threaten the rest of the world. If we learn everything we can about what is happening there, hopefully we will have enough information to convince industrialized nations to reduce emissions and embrace alternative forms of electricity production.