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North America
Climate Change Effects
US National Assessment of
the Potential Consequences
of Climate Variability and Change
Mega-Region: Native Peoples /
Native Homelands
American Indians and the indigenous peoples of Alaska, Hawaii, and the Pacific and Caribbean islands comprise almost 1% of the US population. The federal government recognizes the unique status of more than 565 tribal and Alaska Native governments as "domestic dependent nations." The relationships between these tribes and the federal government are determined by treaties, executive orders, tribal legislation, acts of Congress, and decisions of the federal courts. These agreements cover a range of issues that will be important in facing the prospects of climate change, from responsibilities and governance, to use and maintenance of land and water resources.
Of the approximately 1.9 million people formally enrolled in federally recognized tribes, over half live on hundreds of reservations throughout the country. Within the 48 conterminous states, tribal lands total about 56 million acres, an area about the size of the state of Minnesota. Those who do not live on tribal lands, but instead live in cities, suburbs, and small rural communities across the US, will face the same set of challenges identified in the preceding regional sections. This section focuses on the special set of challenges facing those living on and associated economically, culturally, and spiritually, with reservations and Native homelands. Although the diversity of land areas and tribal perspectives and situations makes generalizations difficult, a number of key issues illustrating how climate variability and change will affect Native peoples and their communities have been identified.
US National Assessment of
the Potential Consequences
of Climate Variability and Change
Mega-Region: Pacific Northwest
The Pacific Northwest (PNW) (Washington, Oregon, and Idaho) is a region of tremendous environmental, economic, climatic, and demographic contrasts. While the diversity of the ecological, economic, and climatological systems of the PNW renders a simple description of the region difficult, much of the region's wealth stems from this very complexity.
US National Assessment of
the Potential Consequences
of Climate Variability and
Change
Mega-Region: Northeast
The Northeast has among the lowest rates of projected future warming compared to other regions of the US. Winter minimum temperatures show the greatest change, with projected increases ranging from 4-5 degrees F (2-3 degrees C) to as much as 9 degrees F (5 degrees C) by 2100, with the largest increases in coastal regions. Maximum temperatures are likely to increase much less than minimums, again, with the largest changes in winter. Model scenarios offer a range of potential future changes for precipitation, from roughly 25% increases by 2100, to little change or small regional decreases. The variability in precipitation in the coastal areas of the Northeast is projected to increase. Models provide contrasting scenarios for changes in the frequency and intensity of winter storms.
US National Assessment of
the Potential Consequences
of Climate Variability and
Change
Mega-Region: Southeast
Temperature trends in the Southeast vary between decades, with a warm period during the 1920s-1940s followed by a cooling trend through the 1960s. Since the 1970s, temperatures have been increasing, with the 1990's temperatures as warm as the peaks in the 1920s and 30s. Annual rainfall trends show very strong increases of 20-30% or more over the past 100 years across Mississippi, Arkansas, South Carolina, Tennessee, Alabama, and parts of Louisiana, with mixed changes across most of the remaining area. There has been a strong tendency for more wet spells in the Gulf Coast states, and a moderate tendency in most other areas. The percentage of the Southeast landscape experiencing severe wetness increased approximately 10% between 1910 and 1997. There are strong El Ni�o and La Ni�a effects in the Southeast that can result in dramatic seasonal and year-to-year variations in temperature and precipitation. El Ni�o events also tend to create atmospheric conditions that inhibit Atlantic tropical storm development, resulting in fewer hurricanes. La Ni�a events have the opposite effect, resulting in more hurricanes.
US National Assessment of
the Potential Consequences
of Climate Variability and
Change
Mega-Region: Midwest
Farming, manufacturing, and forestry characterize the Midwest. The Great Lakes form the world's largest freshwater lake system, providing a major recreation area as well as a regional water transportation system with access to the Atlantic Ocean via the St. Lawrence Seaway. The region encompasses the headwaters and upper basin of the Mississippi River and most of the length of the Ohio River, both critical water sources and means of industrial transportation providing an outlet to the Gulf of Mexico. The Midwest contains some of the richest farmland in the world and produces most of the Nation's corn and soybeans. It also has important metropolitan centers, including Chicago and Detroit. Most of the largest urban areas in the region are found along the Great Lakes and major rivers. The "North Woods" are a large source of forestry products and have the advantage of being situated near the Great Lakes, providing for easy transportation.
US National Assessment of
the Potential Consequences
of Climate Variability and
Change
Mega-Region: Great Plains
While farming and ranching are still the primary land uses of the Great Plains, urban areas provide housing and jobs for two-thirds of the region's people. Native ecosystems and agricultural fields intermingle with small rural communities and the expanding metropolitan centers. The region produces much of the nation's grain, meat, and fiber, including over 60% of the wheat, 87% of the sorghum, and 36% of the cotton. The region is home to over 60% of the nation's livestock, including both grazing and grain-fed-cattle operations. Recreation, wildlife habitat, and water resources are also found on the landscapes of the Great Plains. The Prairie Pothole region provides important habitat for migratory waterfowl. Surface water in rivers, streams, and lakes, and groundwater in aquifers provide water for urban, industrial, and agricultural uses, as well as riparian and aquatic ecosystems. Soil organic matter is a major resource of the Great Plains as it provides improved soil water retention, soil fertility, and long-term storage of carbon.
US National Assessment of
the Potential Consequences
of Climate Variability and
Change
Mega-Region: West
The West has a variable climate, diverse topography and ecosystems, an increasing human population, and a rapidly growing and changing economy. Western landscapes range from the coastal areas of California to the deserts of the Southwest to the alpine meadows of the Rocky and Sierra Nevada Mountains.
Since 1950, the region's population has quadrupled, with most people now living in urban areas. Thus, once predominantly rural states are now among the most urban in the country. The economy of the West has been transformed from one dominated by agriculture and resource extraction to one dominated by government, manufacturing, and services. National parks attract tourists from around the world. The region has a slightly greater share of its economy in sectors that are sensitive to climate than the nation as a whole; these include agriculture, mining, construction, and tourism, which currently represent one-eighth of the region's economy.
As a result of population growth and development, the region faces multiple stresses. Among these are air quality problems, urbanization, and wildfires. Perhaps the greatest challenge, however, is water, which is typically consumed far from where it originates. Competition for water among agricultural, urban, power consumption, recreational, environmental, and other uses is intense, with water supplies already oversubscribed in many areas.
US National Assessment of
the Potential Consequences
of Climate Variability and
Change
Mega-Region: Alaska
Alaska spans an area nearly a fifth the size of the entire lower 48 states, and includes a wide range of physical, climatic, and ecological diversity in its rainforests, mountain glaciers, boreal spruce forest, and vast tundra, peatlands, and meadows. It contains 75% by area of US national parks and 90% of wildlife refuges, 63% of wetlands, and more glaciers and active volcanoes than all other states combined. Direct human pressures on the state's land environment are light, but pressures on its marine environment from large commercial fisheries are substantial. Lightly populated (614,000 people) and growing about 1.5% per year, Alaska has the nations' highest median household income, with an economy dominated by government (44% of incomes) and natural resources (oil 35%, fisheries 7%). Diverse subsistence livelihoods, practiced primarily by native communities, depend on fish, marine mammals, and other wildlife, and play a social and cultural role vastly greater than their contribution to monetary incomes.
US National Assessment of
the Potential Consequences
of Climate Variability and Change
Mega-Region: US Affiliated Islands
The Caribbean and Pacific islands that are affiliated with the US provide a unique setting for consideration of climate variability and change. Islands contain diverse and productive ecosystems, and include many specialized and unique species. After centuries of depending on subsistence agriculture and fishing, island economies are now based heavily on tourism, tuna processing and transshipment, and agricultural production for export (including sugar cane, bananas, pineapple, spices, and citrus fruits), making them highly responsive to external economic forces. The stability of these economies is also dependent on the health of the unique natural resources, all of which are sensitive to climate.
Many islands are facing the stresses of rapid human population growth, increasing vulnerability to natural disasters, and degradation of natural resources. Droughts and floods are among the climate extremes of most concern as they affect the amount and quality of water supplies in island communities and thus can have significant health consequences. Due to their small size and isolation, many islands face chronic water shortages and problems with waste disposal. Some are facing a species extinction crisis; for example, the Hawaiian Islands have the highest extinction rate of any state in the nation. For most island communities, infrastructure and economic activities are located near the coast, making them highly vulnerable to storm events and sea-level fluctuations.
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