Climate change impacts in the Polar Regions

Climate change impacts in the Polar Regions - what the IPCC 4th Assessment Report has found:

• For several decades, surface air temperatures in the Arctic have warmed at approximately twice the global rate [15.2.1].
• In both polar regions, climate change will lead to decreases in habitat (including sea ice) for migratory birds and mammals [15.2.2, 15.4.1], with major implications for predators such as seals and polar bears [15.2, 15.4.3] Reproductive success in polar bears has declined, resulting in a drop in body condition, which in turn is due to melting arctic sea ice. Without ice, polar bears cannot hunt their favorite prey, seals [1.3.5.4].
• Change in composition and range of plants and animals on the Antarctic Peninsula and on the sub-Antarctic islands. Increase in the overall greenness of parts of the Arctic and also in the Antarctic Peninsula [1.3.1.1].
• Changes in position of the northern limit of trees. Increase in biological productivity and change in species ranges (e.g., shifts from tundra to shrublands).
• The pole-ward migration of existing species and competition from invading species (will continue to alter species composition and abundance. Associated vulnerabilities pertain to biodiversity and the spread of animal-transmitted diseases beyond the Arctic) [TS4.2, 15.4.2, 15.4.2, 15.2.2].
• Observed hydrologic and cryospheric changes impacts on Arctic freshwater, riparian and near-shore marine systems.
• The retreat of arctic sea ice over recent decades has led to improved marine access, changes in coastal ecology/biological production, adverse effects on many ice-dependent marine mammals and increased coastal wave action [TS4.2].
• Warming of areas of the northern polar oceans has had a negative impact on community composition, biomass and distribution of phytoplankton and zooplankton [TS4.2 &15.2.2].
• Projections of change agree that retreat of glaciers will continue across arctic glaciers, with a consequent impact on global sea level [15.3.4].