module #9

"How are climate, terrestrial ice and Alaskan indigenous cultures all connected?"

The number one key that connects the above 3 topics is water. More than 2/3 of all fresh water is stored in glaciers. During the various ice ages there have been long periods of colder climate with ice sheets covering much of the Earth. Shorter periods of time called Interglacial periods show glaciers advancing or receding in response to shorter-term climate cycles. Earth's climate cycles have regulated ice ages over millions of year.

As populations grew, people migrated to new parts of our Earth. Humans were and still remain part of a biological succession- as ice sheets and glaciers receded, people moved to emerging landscapes ( terra firma.)

New snow that accumulates and compresses turns into dense, clear ice. Ice fields are created in this manner. Inland glaciers flow out of high mountain areas until they get to lower elevations where they melt forming rivers that go to the sea. Many glaciers' melted waters go directly into the ocean as ice-tidewater glaciers. Water is constantly entering the oceans from melt off of terrestrial ice. Presently, glaciers are melting faster than being built up. These glaciers are called receding glaciers; most glaciers have been in a receding 'mode' since the last glaciation. What is newsworthy is the fast rate of glacier receding. Variables that cause climate change are not always gradual. The Americas were settled shortly after the ice melted. People will always be forced to move locations in response to sea level dynamics.

Once again, a warming effect on our Earth's polar areas caused by snow and ice cooling, resulting in a decrease energy absorbed, decreases the cryosphere or ice area. Melting of snow and ice accelerates climate change. Warm temperatures melt snow and ice and decreases Earth's albedo. This in turn causes more warming and melting. Satellites can make large-scale observations of ice cover over a year's times for a specific area. Instruments on the satellite records electromagnetic radiation in a range of wave lengths. Images are created with color assigned to differing wave lengths- this lets scientists visualize the information.

Climate is the long term environmental analysis of temperature and precipitation averages and ranges. This gives us a reliable estimate of expected normal conditions. Gradual changes in the Earth's tilt, rotation and orbit over thousands of years has caused a change in climate. It seems that Earth's climate responds rapidly once certain boundaries are set in place. Are we seeing this phenomenon? It is thought by climatologists, that heat energy transfer by ocean currents from the tropics to the higher latitudes is caused by a decrease in salinity. The melted snow and ice of the pole's glaciers and ice sheet fields adds a tremendous amount of fresh water into the oceans.

The global climate is seldom stable for long periods of time. Ice samples from Greenland provide a time frame of temperatures from the last 100,000 years. Earth has experienced recurring warm periods in the past. Any transitions between warm and cold periods are displayed as extremely abrupt climate changes. We do not know if the current temperature changes are out of synch or within the cadence of Earth's natural climatic flux. Scientists feel these changes are a result of industrial emissions of heat trapping carbon dioxide and other gases.

Ice affects the Earth's system; it prevents warm ocean water from evaporating, transferring heat to the colder atmosphere and increases global air temperature. Ice reflects light preventing added heat being absorbed by water or land. When sea ice forms, it gives off pure water and leaves behind salt, thereby increasing the salinity of the oceans. Cold salt concentrated water is dense and sinks to the bottom areas of our oceans. This salinity change moves ocean currents. from the equator towards the poles. Coverage and thickness of glaciers and sea ice have decreased over the last 30 years. Small changes in ice volumes have a significant impact on global climate, ocean current patterns and habitats. Ice shelves could break of the Antarctic continents, causing a huge rise in global sea levels with resulting coastal flooding.

Glacial melting i.e. the receding of glaciers has been going on since the 1900's. The retreat of glaciers is repositioned to be caused by global warming. The melting of valley glaciers could cause drastic flooding followed by long-term droughts that would affect millions of people who rely on water for agriculture and drinking water.

Indigenous peoples who live on the coastal Arctic shores are aware of these changes because they have lived in the area over generations and oral traditions teach of the landscape and how to hunt and live as one with the land and sea. The People have seen a gradual rise in sea level, less yearly ice, receding glaciers, and loss of Arctic mammal's habitat ( walrus, seal, whale and polar bear.)

As a summary, climate that is warming is causing terrestrial ice to melt at a faster rate than in the past 100 years. This melting of fresh water could cause salinity changes in the oceans with the denser salinity dropping toward the bottom causing ocean current changes. Possible raised ocean levels would cause flooding of coastal communities and less insulative snow and ice cover. This cycle could cause changes of sea levels, fresh water sources, ocean currents and land mass. People could be forced to inland areas ( the village of Shismarof, Alaska is a case in point.) where they wouldn't have a knowledge of the landscape, animals or migratory habits of animals. This no longer is gong to affect just the people who live at the poles, or within Alaska, but a cataclysmic change in sea levels, more melted fresh water, due to less terrestrial ice could cause devastation for people world-wide.