Spaceship Earth: A new view of environmentalism Spaceship Earth enters 2012 belching smoke, overheating and burning through fuel at a frightening rate. It's feeling pretty crowded, and the crew is mutinous. No one's at the helm. Sure, it's an antiquated metaphor. It's also an increasingly apt way to discuss a planet with 7 billion people, a global economy, a World Wide Web, climate change, exotic organisms running amok and all sorts of resource shortages and ecological challenges. (Courtesy of NASA) - More and more environmentalists and scientists are talking about Eartg as a complex system, one that human beings must aggressively monitor, manage and sometimes reengineer. Kind of like a spaceship. More and more environmentalists and scientists talk about the planet as a complex system, one that human beings must aggressively monitor, manage and sometimes reengineer. This is a sharp departure from traditional "green" philosophy. The more orthodox way of viewing nature is as something that must be protected from human beings - not managed by them. And many environmentalists have reservations about possible unintended consequences of well-meaning efforts. No one wants a world that requires constant intervention to fix problems caused by previous interventions. At the same time, "we're in a position where we have to take a more interventionist role and a more managerial role," says Emma Marris, author of "Rambunctious Garden: Saving Nature in a Post-Wild World." The easy answer used to be to turn back time and make it look like it used to. Before was always better. Before is no longer an option. Although Marris is speaking about restoration ecology - how to manage forests and other natural systems - this interventionist approach can be applied to the planet more broadly. In his book "The God Species: Saving the Planet in the Age of Humans," environmental activist Mark Lynas writes, "Nature no longer runs the Earth. We do. It is our choice what happens from here. The wilderness movements of John Muir in the 19th century and Teddy Roosevelt in the early 20th sought to draw boundaries between civilization and nature. The goal was to protect the biggest mountains, the deepest gorges, the wildest places, according to Douglas Brinkley, author of "The Wilderness Warrior: Theodore Roosevelt's Crusade for America." But after Rachel Carson published "Silent Spring" 50 years ago, detailing the ecological damage from the pesticide DDT, the movement began looking more at industrial pollutants and hazards to human health, Brink­ley says. Then, in the 1990s, climate change began to dominate the discussion. This is a different planet in key respects than the one Carson was writing about. The fingerprints of humankind are now found on every continent, in every sea. Radiation from atomic tests can be found in sediments across the world, and the chemical signature of the Industrial Revolution, when coal began to power human activity, can be seen in ice cores drilled in Greenland. Earth is warming even as a growing human population is demanding more energy, using more resources, burning more fossil fuels and emitting more greenhouse gases. The challenges have scaled up. As a result, some influential thinkers argue for a managerial approach to the planet that is short on sentiment and long on science and technology.