During the last two centuries, billions of years of nature's work has been rapidly transformed by one species—our own. Human beings have dominated life on this planet through advancement in technologies, growth in population, development of land, and exploitation of natural resources.
Scientists have documented five mass extinctions in the Earth's history. Today, many experts believe we are experiencing the sixth, the greatest mass extinction since the dinosaurs disappeared. Some biologists estimate that 5 million species inhabit the Earth, but with undocumented discoveries, the number could be several times higher.
Within the next few years, destruction of rich ecosystems like coral reefs—which support an estimated 1 million species—could wipe out more than a quarter of the world's existing plant and animal species. Earth's biodiversity is being destroyed.
The most important steps needed to promote biodiversity in the national parks are identical to those needed to save the global environment generally. These steps require deep changes in humanity's relationship with nature and in its patterns of resource consumption:
- Global population growth must be stabilized to restrain human resource use so that all of the Earth's natural capital is not liquidated for our species alone, leaving no room for other living things.
- Global warming must be curtailed by cutting emissions of greenhouse gases. These objectives are imperative and lie at the heart of reversing habitat loss, and the related loss of natural biodiversity, in the United States and internationally.
The National Park System offers some of the best protection possible for some of our greatest wild lands. The laws governing parks require that the lands be preserved for future generations, recognizing that they are a gift to the nation and to the future. In many ways, national parks represent the lands the nation values most and for which it seeks the strongest and best protection.
If we cannot protect biodiversity on these nature preserves, then we probably can't save it anywhere.
But if park managers can conserve and restore our extraordinary living heritage of wild lands and wild creatures, national parks 
will provide a model for others to follow in protecting natural lands throughout the world.
