The escalating global ecological crisis – characterized by loss of natural habitat and ecosystem services, increasing species extinctions, and rapid warming of the planet – has demonstrated that conservation efforts to date have not been sufficient to sustain life on earth. While this has been happening, our ecological knowledge has also increased dramatically, especially concerning how much land and water we must protect to support life on Earth. Many assessments over the last 20 years have typically determined that nature needs at least half of a given eco-region to be protected, and needs to be interconnected with other such areas, in order to maintain its full range of life-supporting, ecological and evolutionary processes, the long term survival of the species that live there, and to ensure the system’s resilience in the face of environmental change. Some ecosystems will require more than half.
Until now, the conservation community has been cautious in setting such significant, science-based targets for protecting nature. This cautiousness has been due in part to uncertainty regarding how much of an ecosystem must be protected to ensure its viability (on which there is now much clearer science) and in part to the fact that the conservation community has sought to provide estimates that policy makers would find politically acceptable enough to act upon.
The conservation community and policy makers should now fearlessly embrace a global goal of protecting at least half of the planet’s lands and waters, region by region, in interconnected protected areas. We have a duty to speak frankly about the clear implications of the science. Failure to do so would be the ultimate disservice to people and planet alike. There is a compelling need for a new vision for how much of the planet can and should be protected.
Simply put, Nature Needs Half™, and it is time to say so.