Given the dim-witted ignorance of science currently being manifested by prominent Republicans (from Rick Santorum’s cynical climate-change denial to Rush Limbaugh’s obvious misconceptions of how the birth control pill works), it was refreshing to read a story this week in a magazine as popular as Time outlining very concisely the influence billions of human beings are having on the natural world-
For a species that has been around for less than 1% of 1% of the earth’s 4.5 billion-year history, Homo sapiens has certainly put its stamp on the place. Humans have had a direct impact on more than three-quarters of the ice-free land on earth. Almost 90% of the world’s plant activity now takes place in ecosystems where people play a significant role. We’ve stripped the original forests from much of North America and Europe and helped push tens of thousands of species into extinction. Even in the vast oceans, among the few areas of the planet uninhabited by humans, our presence has been felt thanks to overfishing and marine pollution. Through artificial fertilizers – which have dramatically increased food production and, with it, human population – we’ve transformed huge amounts of nitrogen from an inert gas in our atmosphere into an active ingredient in our soil, the runoff from which has created massive aquatic dead zones in coastal areas. And all the C02 that the 7 billion-plus humans on earth emit is rapidly changing the climate – and altering the very nature of the planet.
Human activity now shapes the earth more than any other independent geologic or climatic factor. Our impact on the planet’s surface and atmosphere has become so powerful that scientists are considering changing the way we measure geologic time. Right now we’re officially living in the Holocene epoch, a particularly pleasant period that started when the last ice age ended 12,000 years ago. But some scientists argue that we’ve broken into a new epoch that they call the Anthropocene: the age of man. “Human dominance of biological, chemical and geological processes on Earth is already an undeniable reality,” writes Paul Crutzen, the Nobel Prize-winning atmospheric chemist who first popularized the term Anthropocene. “It’s no longer us against ‘Nature.’ Instead, it’s we who decide what nature is and what it will be.”
To carry this line of reasoning one step further: with the advent of genetic engineering and the growing understanding of human psychology and neurology, it is also we who might decide what human nature will be. That old Existentialist adage, “existence precedes essence,” used to apply just to one’s own self-understanding; the suggestion was that, from the subjective viewpoint of lived experience, one first finds oneself existing, and then discovers that one’s “essence” or “nature” follows from what one chooses to do. But now it appears that this might soon become true not just from a subjective point of view, but also from an objective, scientific one: it seems that not only human nature, but also nature itself has become our responsibility. And given our track-record up to now, this should certainly cause some angst.