Set up a journal to take notes as you participate in this module. Your journal can be an online tool or offline notebook - whichever works for you and your learning style.
Impacts of a Warming Arctic
In the Earth system, a change in one part of the system will lead to a change in another part through positive and negative feedbacks. Feedbacks render some parts of the Earth more sensitive to climate change than others. Examine the evidence for changes in ice cover at the Arctic and explore why climate changes at the poles are so important to the rest of the climate system.
Changes in the amount of ice at the poles profoundly affect the climate across the whole planet. In winter, ice at the Arctic grows out to be about twice the size of the continental U.S. In recent memory, the ice used to melt back to about the size of the continental U.S. in summer. Now, however, the ice is melting back to about half that size. The areal extent of sea ice is important: Arctic ice surfaces reflect the Sun's heat back out to space. Less ice means less reflection and more heat retained in the Earth's atmosphere. Find out why the Arctic is predicted to warm faster than anywhere else on Earth and why this is important to the rest of the climate system.
The AAAS Benchmarks for Science Literacy call out the importance of understanding that:
- The Earth's climates have changed in the past, are currently changing, and are expected to change in the future, primarily due to changes in the amount of light reaching places on the earth and the composition of the atmosphere (4B/H6).
- The use of tables, charts, and graphs in making arguments and claims in oral, written and visual presentations (12D/H7);
- Exploring the structure and function of systems (11A/M2; 11A/H1); and
- The use of systems analysis in understanding natural systems (11A/M5).
These benchmarks correspond to Content Standard C: Life Science, and Content Standard D: Earth and Space Science, of the National Science Education Standards.
In this module, you will::
- Examine graphical data sets and scientific visualizations and evaluate evidence for decreasing sea ice cover and land ice in the Arctic.
- Trace the feedbacks in the Earth system that are responsible for the sensitivity of the Arctic to global climate change impacts.
The Earth's cryosphere (the frozen water on our planet) currently covers about 10% of the Earth's surface, but for how much longer? Ice exists in many forms, for example, as continental glaciers at higher elevations in mountainous regions around the world; as sea ice in the Arctic; as ice sheets in Greenland; as ice shelves, thick slabs of ice that extend from continental Antarctica's coast over the ocean, and as permafrost in the ground.
Changes in the amount of ice at the poles profoundly affect the climate across the whole planet. The melting of sea ice does not play a role in increasing the volume of water as does melting ice sheets and glaciers, but sea ice plays an important role by reflecting sunlight, keeping the poles cool and regulating climate on our planet.
The melting of continental ice sheets, on the other hand, does contribute to sea level rise by increasing the volume of water in the ocean. In 2007, the best interpretation of data at hand suggested to the Intergovernmental Panel on Climate Change (IPCC) that we might expect a sea level rise of between 7-23 inches by 2100. Now, only a few years later, unexpected and accelerated melting observed in Greenland and Antarctica suggest to some researchers that a sea level rise of 3-6 feet by 2100 is more likely.
Explore how changing climate has caused a change in the amount of ice in the Arctic and how decreased ice area contributes to greater warming in other parts of the globe.
NASA and PBS
This professional development experience was funded by NASA's Global Climate Change Education initiative. This initiative is designed to improve the quality of the nation's STEM (Science, Technology, Engineering, and Mathematics) education and enhance students' and teachers' literacy about global climate and Earth system change from elementary grades to lifelong learners.
© 2010-2012, PBS. All rights reserved.