Earth Day marks its 35th anniversary on Friday. Founded in 1970 by then Wisconsin Sen. Gaylord Nelson, its goal was to raise awareness nationwide about the cost to life on Earth of such things as pollution, habitat loss and the extinction of species.
More than three decades later, progress has been made in some areas, while decline has been seen in others. But our ability to use science to understand it all has increased, and we are increasingly aware how environmental issues in one part of the world can have an impact thousands of miles away.
At 9 p.m. Wednesday and April 27, PBS presents a four-hour miniseries called "National Geographic's Strange Days on Planet Earth," with host and narrator Edward Norton ("American History X," "Fight Club"). Drawing upon research from the new discipline of earth system science, it seeks to understand the long-range effect of humans on the planet.
Norton is the grandson of renowned urban planner James Rouse and the son of Edward M. Norton Jr., who advises the Nature Conservancy. Norton is also partnered with his younger brother, filmmaker Jim Norton ("Yunnan Great Rivers Expedition"), in Class 5 Films.
Norton and his brother were originally planning to do a film about an area of China where the elder Norton is working through the Nature Conservancy. They approached National Geographic, which steered them toward the Sea Studios Foundation and producers Mark Shelley ("The Shape of Life") and David Elisco, who were developing a series of films with similar themes.
In the end, Norton's behind-the-scenes involvement morphed into an on-screen role in the series, eventually called "Strange Days on Planet Earth." From his home base in a lawn chair on a typical suburban street, Norton leads a globe-circling survey of environmental challenges.
"This is a big part of our family's life," Norton says. "So it seemed like a natural opportunity to intertwine some of my interest in narrative storytelling with issues and themes that are important.
"I said, 'Are you sure you don't want to get Anthony Hopkins or something? I can try to find you one of those great voices.' And they said, 'No, one of our main goals in this is to try to reach a younger generation of people and engage them in these issues. We'd really like to have someone younger.' "
Episode one, "Invaders," looks at how alien species of plants and animals, whether imported accidentally or intentionally, have had a devastating effect on their new environments, from spreading disease to displacing native species.
Also that first night is "The One Degree Factor," which explores whether global climate change is responsible for such seemingly unrelated issues as dust clouds over the Atlantic, respiratory illness among children in Trinidad and shrinking populations of caribou.
"Predators," premiering April 27, looks at what happens when top predators such as wolves are removed from the environment.
It's paired with "Troubled Waters," which tracks the implication of pollution from the deaths of beluga whales in the St. Lawrence River in Canada to an overabundance of sea stars in Australia's Great Barrier Reef.
"You don't want to just be the person waving the placard, 'The End is Near,' but by the same token, it would be a shame if we didn't come to grips with the degree of collapse that is possible and imminent," Norton says. "You really wonder if, in our lifetime, we're going to see a threshold crossed, perhaps in terms of fishery collapse.
"It was a huge education for me, because what was being rolled around in it was so interesting and cutting-edge. It was a great thing to grip people's interest and try to bring more people into the conversation."
As controversial as the problems and solutions discussed in "Strange Days" can be, one thing Norton doesn't want to do is bring politics into the environmental equation.
"I've always thought, that it was an incredibly crass manipulation to throw the mantle of liberalism onto environmentalism," he says. "It's such a fallacy to ascribe a political component to environmental consciousness.
"It's something that, by definition, supersedes politics, in that it affects all of us, and it's not really a question of liberal or conservative, or Republican or Democrat. It's a question of denial or open-eyed confrontation of scientific reality that has consequences for all of us equally."