Over the last several hundred years, human civilization has declared war on large mammals, leading some respected ecologists to assert that the only large mammals to survive the near future will be those we humans choose to allow to live.
Other prominent biologists, aghast at the wholesale devastation of tropical rainforests and temperate old-growth forests, rapidly accelerating desertification, and destruction of "charismatic megafauna" due to habitat destruction and poaching, say that Earth could lose one quarter to one third of all species within a very few years.
Not only is the blitzkrieg against the natural world destroying ecosystems and their associated species, but our activities are now beginning to have fundamental, systemic effects upon the entire life-support system of the planet - upsetting the world's climate, poisoning the oceans, destroying the ozone layer which protects us from excessive ultraviolet radiation, changing the CO2 ratio in the atmosphere, and spreading acid rain, radioactive fallout, pesticides and industrial contamination throughout the biosphere.
Indeed, some biologists have warned that vertebrate evolution may be at an end due to the activities of humans.
Clearly, the conservation battle is not one of merely protecting outdoor recreation opportunities; neither is it a matter of elitist aesthetics, nor "wise management and use" of natural resources. It is a battle for life itself, for the continuous flow of evolution.
We - this generation of humans - are at our most important juncture since we came out of the trees six million years ago. It is our decision, ours today, whether Earth continues to be a marvelously living, diverse oasis in the blackness of space, or whether the charismatic megafauna of the future will consist of Norway rats and cockroaches.