• Introduction
• Background
  • Arctic Ecosystems
  • The Carbon Cycle
  • Phytoplankton
  • Sea Ice
  • A Warming World
• The Arctic Ecosystem Model
  • How to Read the Model Results
    • Concentration versus Time and Depth
    • Results as a Series of Vertical Profiles
  • Model Components
    • Nitrogen and Phytoplankton
    • Nitrogen, Phytoplankton, Zooplankton
    • Nitrogen, Phytoplankton, Detritus
    • Nitrogen, Phytoplankton 1, Phytoplankton 2
    • Nitrogen, Phytoplankton, Zooplankton, Detritus
    • Nitrogen, Phytoplankton 1, Phytoplankton 2, Zooplankton, Detritus
  • Sensitivity Experiments
    • Model Settings
    • Ocean Settings
    • Phytoplankton Settings
    • Zooplankton Settings
    • Start Day and Latitude
    • Nitrogen, Phytoplankton1, Phytoplankton2, Zooplankton
  • Detailed Explanation of Terms
    • K for Nitrogen
    • K for Phytoplankton
    • Growth_o
    • K and Growth_o: 2 Phytoplankton Taxa
    • Ek_max
• Model Scenarios
  • Phytoplankton Competition
  • Late versus Early Phytoplankton Blooms
  • A Warming World

Sea Ice

The polar regions are expected to be particularly sensitive to warmer temperatures. Higher levels of CO₂ in the atmosphere lead to warmer temperatures in most parts of the world, including warmer temperatures in the world's oceans. Not only do surface waters heat up, but patterns of ocean circulation change, and sometimes warm water flows into a region that used to have cold water. These warmer temperatures melt more sea ice than usual in the summer and cause less sea ice to form in the winter.

Additionally, sea ice has a particularly strong feedback within the climate system. Sea ice reflects 50-90% of the sunlight that strikes it, absorbing little energy. Meanwhile, open ocean reflects less than 10% and absorbs the rest*. When there is less ice, the ocean absorbs significantly more solar energy and warms up more, causing more ice to melt.

The ice provides important habitat for polar bears and seals, as well as microscopic organisms like ice algae (algae that live within or attached to sea ice). Changes in sea ice will have a dramatic effect on life on earth, determining the fate of sensitive species such as polar bears, and influencing climate in places as far away as the equator.

*Open a more detailed discussion of albedo in a new window