The world's burgeoning population (the United States alone will see its population grow by an additional 120 million by 2050) demands both abundant goods and services and a high quality environment.  Increasingly, the capacity of nature to produce essential services -- the resources produced by the environment that we often take for granted such as clean water and air, soil productivity, pollination, scenic beauty, and many more -- is becoming strained.  At the same time, demand for nature's services is growing.  In the face of this growing scarcity, it has become clear that there is an urgent need to think strategically about how to design new policies for conservation that can engage both public policy and private enterprise in new ways to conserve and enhance environmental services.

In much of the industrialized world, conservation has focused on public land systems, tax subsidies and regulatory incentives for forest management, and private land protection by philanthropically inclined landowners. Rising raw material prices helped provide incentives to private forestland owners to manage their lands for forestry purposes, but other ecosystem services produced by those forests and wild lands went unpriced. Those services provided by nature for free are the essential life support systems on which all life depends and the earth’s economies rely. Yet, because they remain unpriced in the marketplace, they are subject to over-exploitation in a manner that has been described as the "tragedy of the commons" (a metaphor used to illustrate the conflict between individual interests and the common good, popularized by Garrett Hardin in his 1968 Science article of the same name).

The challenge of protection is enormous. Mark Shaffer, J. Michael Scott, and Frank Casey writing in the journal BioScience estimate that to protect the remaining stocks of biological diversity in the United States, a comprehensive system of habitat conservation areas of approximately 236.4 million acres of land would be required in addition to the lands already in public ownership.  The cost of such a system of protected areas, if all were held in conservation easements, would be approximately $400 billion if easements could be purchased at the current average cost of approximately $1,700 per acre.  That compares to the 6,225,225 acres of land protected by local and regional land trusts as of the year 2000.