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Essential Questions:
Essential Questions:
- How are Alaska's natural systems interconnected?
- How have Alaska's natural systems changed over time?
- How does digital information change our understanding of natural systems?
- How does knowledge of natural systems inform our understanding of cultural systems?
- How does knowledge of natural systems relate to the roles of educators?
ENGAGE
Pleistocene epoch, ice age, interglacial period, last glacial maximum--it's all a bit confusing until we tease out what these different terms mean and how they help us understand the long history of terrestrial ice on Earth.
Put simply, ice ages are longer periods of colder climate during which ice sheets cover much of the Earth. Interglacial periods are shorter periods of time in which glaciers periodically advance or recede in response to shorter-term climate cycles within the present ice age.
The maximum extent of the last glaciation (LGM) occurred about 18,000 years ago. Except for comparatively brief recent periods, glacial recession has been the norm for quite a while--ever since the last interglacial period ended about 12,000 years ago.
During the LGM, a person could have walked from Alaska to New York across an uninterrupted ice sheet, in places thousands of feet thick. Now, except for the return of seasonal snow each winter, the landforms of most of North America are clear of most of the snow and ice that covered so much it for about 100,000 years.
Thousands of years ago, Earth's climate was again beginning to warm for reasons related to large complex climatic cycles that have regulated ice ages over millions of years.
With just a few million people world-wide at the beginning of agricultural settlement about 10,000 years ago, humanity's carbon footprint was the tiniest fraction of our present scale of carbon combustion. But as populations grew and people migrated, humans became part of the post-glacial biological succession, naturally, as ice sheets and glaciers receded and people advanced into the emerging landscapes.
EXPLORE
Teachers' Domain
Taking Earth's Temperature is a TD video that correlates several methods scientists are using globally to measure the rate and extent of climate change.EXPLORE SOME MORE....
Visit NASA's Earth Observatory to see their animation of global seasonal snow between the Feb. 2000 and Sept. 2009. Check out some of the other interesting Earth systems animations while you're there.Visit the Alaska PaleoGlacier Atlas and find interactive maps detailing Alaska's topography and climate.
National Snow and Ice Data Center and Alaska Climate Summaries offer excellent data regarding weather and climate data in specific regions.EXAMINE
- What are some ways Earth's temperature is measured daily?
- How has Alaska's climate changed over millions of years?
- Why is Alaska an important indicator for climate change?
EXTEND
- What are some other sources of credible climate information?
ENGAGE
Climate Control Issues
There's much more to Earth's dynamic climate than the amount of carbon dioxide in the atmosphere at any given time. There are many climate variables that interact in complex cycles over long periods of time.
The Sun's increasing energy output, Earth's changing orbital distance, speed of rotation, tilt, plate tectonics, land-to-ocean ratio, volcanoes, wildfires and even meteorites all play roles in the climate dynamics on this little planet.
But Earth's complex history of atmospheric gases reveals that over millions of years, Earth has moved its carbon stores around using various biological, chemical and geological processes.
And as a result, Earth's climate has fluctuated many times over eons from cold to hot to cold, over and again, more or less gradually, as numerous climate variables interacted over the eons.
For the folks conducting actual climate research, it's big math and big science to fit the pieces the puzzle together properly.
Anthropogenic Climate Change
So how is climate change now any different than in the past? What's causing the recent acceleration in the increase of the average temperature on Earth? In a word, industrialization.
The carbon which nature has been sequestering for hundreds of millions of years, humans have been liberating as carbon dioxide and other greenhouse gases, mostly through our industrial technologies and agricultural practices over the past 150 years.
In short, by re-releasing atmospheric gases from nature's carbon caches at rates far exceeding those nature used to create and store them, humans have thrown some of Earth's intricate systems out of balance. Because everything is connected!
EXPLORE
Teachers' Domain
Here's the basic science of how Earth's different systems interact to regulate the planet's climate. The Physics of the Greenhouse Effect
EXAMINE
- What causes climate to change?
- Why is change sometimes sudden?
- What are some ways Earth naturally stores and releases carbon dioxide?
- What is the role of anthropogenic sources of greenhouse gases?
EXTEND
Sometimes a picture is worth a thousand words.
Information is Beautiful - Climate Change Consensus
Information is Beautiful - Sea Level ChangeENGAGE
When Did the First Americans Arrive?
One thing that is constant is change. Today, Alaska certainly doesn't look anything like it did when humans first started poking around this patch of ground. Starting with the fact that the ocean was lower by hundreds of feet and it was dry land between Asia and Alaska. And giant mammals abounded.So, even though the rate of sea level change is presently increasing, it's easy to see sea level has been rising and falling for quite a while. But what role did sea-level and ice play in the people-ing of places?
EXPLORE
Teachers' Domain
When Did the First Americans Arrive? EXAMINE
- What are some connections between climate, sea-level, glaciers and human migrations?
- What other evidence contributes to ideas about human migrations in North America?
- What are the likely routes taken by North America's earliest human inhabitants?
ENGAGE
Cultural Connections
In April, 2009, representatives of indigenous peoples from across the planet converged on Anchorage, Alaska to discuss the impacts of climate change in their respective regions - Indigenous Peoples' Global Summit on Climate Change, hosted by the Inuit Circumpolar Council.
Along with developing strategies to help curtail changes, as well as adapt to them, representatives also worked to improve cultural understanding in order to help assure the sustainability of indigenous cultures living closest to the land and traditionally relying most directly on its natural resources.
It's reasonable that those who have lived close to nature for many years are going to be first to notice changes. Science has a great deal to tell us about the Big Picture, but our friends and neighbors who rely on nature's abundance to survive don't need a scientist to see that sometimes change comes quickly.
Teachers Domain
Check out these TD videos on the impacts of climate change on cultures that have depend on Arctic sea-ice.
Global Warming Threatens ShishmarefArctic Climate PerspectivesHunters Navigate Warming ArcticEXAMINE
- What is the role of sea-ice in providing food for Arctic people?
- How has the unpredictability of seasons changed the lifestyle of Arctic peoples?
- What are the local indicators of climate change where you live?
- What cultural resources can you use to describe local changes?
- What other digital resources reflect the climate perspectives of indigenous peoples?
What's Next?
Now it's time to ask the question, "How do you Google Earth?
