Date of this Version
Jezierski, C., R. Loehman, and A. Schramm. 2010. Understanding the science of climate change: Talking points - impacts to Alaska Maritime and Transitional. Natural Resource Report NPS/NRPC/NRR - 2010/223.
Alaska is a huge state spanning 375 million acres and occupying nearly one-fifth of the land area for the contiguous 48 states. More than half of the coastline of the entire United States is in Alaska. Due to the great size and geographically diverse nature of Alaska, two bioregional documents were produced: “Boreal and Arctic” and “Alaska Maritime and Transitional.” In Alaska, the vast majority of the land is public; with approximately 222 million acres (approximately 60%) designated federal lands and another 90 million acres (approximately 24%) in state ownership. There are 17 National Park Service (NPS) areas in Alaska covering over 54 million acres; this represents two-thirds of the land in the entire National Park system. Wrangell-St. Elias is the largest NPS unit at over 13 million acres in size. There are 16 National Wildlife Refuges in Alaska totaling over 76 million acres, representing approximately 80% of the entire National Wildlife Refuge system. The two national forests in Alaska encompass nearly 22 million acres; Tongass National Forest is the largest United States Forest Service unit, with nearly 17 million acres. The Bureau of Land Management manages almost 78 million acres in Alaska.
Climate changes in the Alaska Maritime and Transitional bioregion include increased mean, minimum, and maximum annual temperatures, and increasing spring and wintertime temperatures that have resulted in a longer growing growing season and shifting plant distributions. Regional models project a wintertime shift in temperatures from below to above freezing by the mid to late 21st century, a decrease in the annual number of snow-free and frost-free days, and a mean increase in annual air temperatures. Observed hydrologic changes within the bioregion are profound, including significant decreases in the number, mass, and volume of glaciers; increased rates of glacial retreat and thinning; increased volume of glacial runoff; and increasing stream temperatures. Projections for the coming century include further changes in seasonal and annual precipitation patterns (both snow and rainfall), continued drying of existing wetlands, and sea level rise resulting from continued melting and retreat of glaciers. Observed and predicted bioregional changes in temperature and hydrology affect vegetation and wildlife through altered seasonality of runoff, increased wildfire and insect activity, movement of forests and shrublands into wetlands and recently deglaciated areas, phenological shifts (altered timing of reproductive events such as fish spawning and bud burst), and major directional and elevational shifts in plant distributions and community assemblages. Direct effects of bioregional climate changes on human populations and infrastructure are structure damage from thawing permafrost, altered soil conditions, and shifts in water and plant communities, which may, in turn, affect animal communities and alter fire regimes. Changes in terrestrial and marine wildlife distributions may affect visitor viewing opportunities and complicate subsistence hunting throughout the region.