Ice Cold Science

Explain

The Cryosphere (Greek for cold) is the frozen water on the earth’s surface. Sea ice, glaciers, ice caps, ice sheets and permafrost are all considered to be a part of the cryosphere. Most lakes and rivers begin freezing at around +4C, but because of increased salinity, the ocean surface has to get down to -3C before it starts to freeze. The majority of the ice found in the Arctic is sea ice. The measurement of how strongly ice (or any other object) reflects light is called albedo. It is a unitless measure that can be represented either as a percentage, or a value between 0 and 1 (0 is dark and 1 is bright). For example, fresh snow has a value of 0.9 and charcoal has a value of 0.04. Albedo works on a small scale when someone who wears dark colored clothing outside in the summer has a higher chance of heatstroke than someone wearing lighter colors. On a large scale, albedo has an effect on warming and cooling the planet. When snow melts and the land underneath begins showing, the albedo decreases and the temperature in that area increases because more light is absorbed. When snow falls and covers the earth, more light is reflected and the albedo effect is cooler temperatures. Ice actually cools the earth in a couple of specific ways. One way that ice cools is because it has a high albedo and reflects light back into space. Ice also absorbs heat as it melts and changes state into water.The equatorial and sub-tropical regions get an excess amount of heat from the sun due to the tilt of the planet. The ocean circulation transfers some of the heat from these warm areas to the north and south to the polar regions where it is lost back to space. Snow and ice at the poles reflect a significant amount of heat away from the planet, which has a cooling effect on the climate. “As it moves north, the Gulf Stream disperses some of its heat into the Northern Hemisphere. Without this, Western Europe would have a Siberian climate.” – Arctic Climate System, TD

Extend

The Arctic marine system is very productive, but the harsh environment means the ecosystem is not as diverse as most other major ecosystems. This lack of diversity means that any disruption to one species’ population has big effects on the other species in the Arctic food web/chain. The more diversified a system is, the more resilient it is to change. This applies in biology, but it also may have implications for cultures as well. Since things are changing in the Arctic, resilience of Arctic peoples and cultures in the future may depend on their ability to diversify their ways of surviving. A NOVA online video shows some of the connections between Alaska Native peoples and the Arctic sea ice and animals who depend on it for survival.

There are four parts, so if you liked this one, there are three more on You Tube.

Evaluate

As the Arctic changes and sea ice decreases, animals supported in our ecosystem here will change. Some of our animals depend on sea ice for food and breeding grounds and to travel across when moving from place to place. These animal populations may not survive such a change. Global scientific studies including satellite data look at a big picture of what is happening on our planet. Native knowledge has a more focused local perspective with the added benefit of knowing firsthand how changes are affecting human, animal and plant populations. Even though the Arctic sea ice is being carefully monitored with both aircraft and satellites, there is also considerable merit to those who physically stand where it is all happening. The human eye for detail and nuance see in a different way than the scientific instruments. The changes in sea ice have implications for Native Alaskan’s livelihood and way of life. When changes happen to our Arctic sea ice, the connection of the ice to the wildlife and to the people changes with it.