The True Tradeoff: Continually Rising Human Populations or Healthy Biodiversity and Ecosystems

Tension between human population growth and natural resources is not sustainable

Sustainability in the long term requires explicitly dealing with the conflict between a growing human population and natural resources. I have encountered this throughout my 34-year career in cold water fish research, natural resource management, ecosystem assessment, habitat restoration, and aquaculture. Throughout these years, I have joined many fisheries colleagues to make the observation that conflicts between natural resources and humans can only produce win-lose situations. Human needs inherently take from nature and nature’s needs, conversely, take from humans. Although fairly clear to my colleagues and me, this has not been part of the overall public discussion. Society’s solution is to focus and narrow the issue so that an acceptable agreement can be reached. This agreement generally accepts a “small” loss of habitat that will most likely result in loss in animal populations. However, cumulatively, the small losses in the animal populations result in significant, major population losses.

Salmon swim upstream to spawn. Photo: Alaska Region U.S. Fish & Wildlife Service on Flickr.

For example, consider the Salmon 2100 Project, in which a group of experts provided a view of the future of wild salmon in the Pacific Northwest in the year 2100. One of the driving forces was the projection that human population in the region would be likely four times higher in 2100 than in 2000. Already, wild salmon and many other natural resources in the area are considered endangered or threatened, with populations that are typically one to ten percent of that when Euroamericans arrived (post 1850). Thus, in simple terms, the current cumulative impact of human development and growth has resulted in degradation of habitats, reduction of populations, and squeezing the remainder into smaller and smaller areas. Human development takes its toll on the wild salmon’s habitat through water consumption, power production, growing food, harvesting lumber and wood fiber, and transportation needs. If population in the area is to be four times higher in 2100, maintaining the current wild fish populations would require reduced consumption of these resources to be 25% of what it is today.

While this is obviously a simplistic view, the point is that unless we explicitly and holistically address not only human population growth but also increasing efficiencies in the use of resources, the future of wild natural resources is bleak. On an individual, farm, tree farm or community basis, actions can be—and are being—taken to reduce that location’s footprint but these efforts equate to little ecological benefit if the “savings” are simply transferred to other individuals, farms, tree farms, or communities. Thus, landscape-scale approaches are needed.

Landscape-scale approaches are needed

As an example, current efforts to conduct agriculture in ways that consider the needs of fish and wildlife require forgoing some aspect of food production. As local and global human populations increase there will be an ever-increasing need to produce more food. Intensification of agriculture is a necessary step so that more food can be produced. But, these efficiencies in water use, for example, can only go so far. Food will always require a minimum amount water for production. At some point, human need for food and water will come up against and outweigh the needs of fish and wildlife.

The same is true for all the other demands that humans place on the natural environment. Consequently, the long-term survival of wild salmon and their ecosystems, or any other naturally functioning ecosystem, will depend on ultimately addressing the conflict between human and natural resource needs on both local and global levels.  Nature and humans can, do, and have coexisted. Coexistence becomes more difficult as populations—whether human or animal—increase. As an extreme example, Grizzly Bears were abundant in many parts of California, such as Monterey and Los Angeles. They don’t and can’t live there now. Some resources need extensive space, water, and so on. They will exist so long as we make the decision to allow them to.

How can we continue to work on species and ecosystem restoration, development and implementation of sustainable agriculture, timber harvest, and power production while not bringing local and global human population growth into the discussion?