OVERVIEW
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BURGESS
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Burgess COMMENTARY |
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Natural Resources and Ecosystems The nation's natural resources include: The raw materials used to produce goods and services, for the people in the United States and for export, such as:
The ecosystems that produce those raw materials and the many ecological and ecosystem services that make life on earth possible, such as:
Taking Care of Our Ecosystems Some of the raw materials we use are renewable; that is, they grow and can regenerate themselves. But they can only continue to regenerate and be available to us if we take care of the underlying ecosystems that produce the renewable materials and don't extract the resources at an unsustainable rate. The question is: Are we adequately taking care of the underlying ecosystems? It's difficult to answer that question because the issues are so complex. The United States is over 3.5 million square miles,1 with many different types of natural resources and ecosystems. It includes extensive forests, prime agricultural land, freshwater lakes, and prime saltwater fisheries off our coasts. You can see why it's not possible to report a single number that measures the quality of the nation's natural resources and ecosystem services. And, there is a lack of adequate information to evaluate the state of all these resources. This section of the Calvert-Henderson Environmental Model looks at three indicators of the large issue of natural resources: the state of our water resources, land resources, and biodiversity. As we explain below, these issues are interrelated. Water Resources We discuss water quality in the United States in the Environmental Quality section of this indicator. An equally important issue is water quantity. Our society's thirst for water has been increasing steadily, as can be seen in the graph below. From 1950 to 2000 total withdrawals of water increased 127%.2
Our water use is more than triple other countries with comparable standards of living, such as Sweden, Switzerland, Denmark and the UK.3 Although we have information about the amount of water used in the United States, we don't know how much water can be extracted from our surface and groundwater sources without adversely impacting those sources. In a report to Congress in 2003, the General Accounting Office reported that water managers in 36 of the 50 states expect to have problems with water shortages in the next ten years. Already, rivers such as the Colorado run dry before they reach the ocean. Groundwater supplies-such as the High Plains Aquifer, which underlies eight states in the central portion of the US-are being pumped faster than they are replenished.4 Development and Water Quantity Water quantity is related to how we use our land resources. Studies show that the more land is developed, the less rainwater is able to recharge aquifers-making the water supply problem even worse.5 Without trees and other plants that retain water in the soil, rainwater runs off the land more quickly, leading to erosion, degraded land resources, and sediment in our rivers and streams. Water quantity is also tied to global climate change. Although the annual average rainfall in the United States is almost 30 inches per year.6 the rain doesn't arrive in a consistent pattern; rather, it comes in bursts. When precipitation comes as rain, it runs off quickly. Some of the bursts come in the form of snow that melts gradually as spring arrives. The slow melting allows water to seep into and replenish underground aquifers. However, because of global warming, many places may receive significantly less precipitation in the form of snow. The result? Less water in reserve supplies, which could have an effect on our economy, society, and the ecosystems that depend on water resources. Managing Land Resources Another important natural resource is the land on which other resources are produced. How long will our land resources continue to provide the resources we need? Although various government agencies are attempting to measure the quality of our forests, farmland, pastures and rangeland, a simple answer to that question is not available. We do know, however, the rate at which forest and farmlands are being converted to developed land. And we have an idea of whether undeveloped land is being managed so that it will continue to produce resources over the long term. The graph below, based on information from the US Natural Resource Inventory, shows that more than 45 million acres of ecologically productive land in the United States have been lost since 1982 to sprawling land development.7
Decline in Ecologically Important Land What the graph doesn't show is the potential for even greater loss in the future due to fragmentation and parcelization: breaking larger areas of forest and farmland into smaller and smaller pieces. This practice weakens the health of ecosystems, making them more vulnerable to pests and diseases, and decreasing the habitat available for animals that require large contiguous areas. Fragmentation has an adverse economic effect as well since the economic viability of forestry and farming industries depends on adequate supporting infrastructure-the businesses that supply farmers and foresters. As the number of farms and forests being actively managed decreases, it becomes harder for the supporting businesses to survive. And as those supporting businesses decline, it becomes harder for the foresters and farmers to continue doing business, making it more likely that they will sell their land to developers, further reinforcing the decline in ecologically important lands. Biodiversity One measure of the health of natural resources is the extent to which plants and animals can't survive because the habitat that is critical to their survival is degraded or destroyed.. In the US there are currently 409 animals and 598 plants that are in danger of becoming extinct.8 Global Warming and Ecosystems Another issue affecting biodiversity is the expected effects of global warming on ecosystems. Because of global climate change, by the end of this century, winters in Minnesota may feel like those in Illinois, and summers in Iowa may be as warm as those in Alabama. This effect is called climate migration and the estimated result for Illinois is shown in the picture below.
Although warmer winters with less snow may seem to have some advantage to humans, this change in climate will be a problem for plants and animals, which require certain climates to survive. Plants and animals that have adapted to specific temperature, rainfall, and other climate characteristics over many eons will have problems adapting to new climates. Climate migration will have an effect on farmers' ability to provide food for the nation.9 One example of where this is already being seen is the white spruce forests of Alaska. In the past, the population of spruce bark beetles has been kept in check by freezing Alaskan winter temperatures. However, in the last decade more beetles have been surviving the warmer winters and there have been widespread dieoffs of white spruce.10 In the agricultural industry, changes in temperature and rainfall may dramatically affect the types of plants that farmers can grow. One comprehensive effort to measure and report on the quality of our natural resources is the Heinz Center report, the State of the Nation's Ecosystems, first published in 2002. This and other efforts are described in the Environmental Indicators section. The next part of the environment model, Industry and Infrastructure, affects and is affected by the quality of natural resources. Footnotes:
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| The text being discussed is available at http://www.calvert-henderson.com/enviro-resources.htm |
