During the first Earth Day, people didn't only talk about protecting "the environment." In the early 1970s, it was "the ecology" that needed saving. High schools formed ecology clubs. People slapped ecology bumper stickers on their VW camper vans. Marvin Gaye wrote a hit song about it. But—mercy, mercy me—you don't hear as much about ecology these days.

I suppose the word ecology fell out of favor because it already carried a specific meaning: the relationship between living things and their surroundings. I think it's time to bring some of that focus back to what we now call environmentalism. Our relationship to the natural world is way out of balance, and it's affecting everything from bumblebees to blue whales.

Here's a stat that threw me: Only about 4 percent of the world's mammals, by weight, are wild animals. The other 96 percent are humans and our domesticated livestock. We're altering the atmosphere and our climate. We're changing the oceans. We've even filled outer space with junk. But the most obvious impacts of our domination occur on the ground beneath our feet.

The Sierra Club has spent more than 125 years working to conserve and protect public lands and wilderness—and we've had major successes, from the Arctic to the Everglades. The big picture, though, is worrisome. Excluding Antarctica, less than a quarter of the planet's landmass remains undisturbed by industrial activity and human development. Civilization's environmental footprint is more like a body slam.

We're now facing a major extinction crisis. And even if we don't care what happens to other living creatures (and we ought to), the loss of wilderness and protected lands directly affects us, because we're all part of the same grand ecosystem.

How we manage our public lands in the coming decade will also be a crucial part of our response to the climate crisis. Owing to fossil fuel extraction, an estimated one-fifth of US greenhouse gas emissions comes from public lands—and the Trump administration wants to drive those emissions up by opening more lands to coal mining and drilling for oil and fracked gas. Instead of destroying public lands, we should be using them to sequester carbon.

Those are just some of the reasons the Sierra Club is joining a global movement that calls for an ambitious vision of lands and water protection. The eminent biologist E.O. Wilson has argued that to preserve biodiversity, we need to set aside half the planet for wild nature. Now, conservation organizations including the Sierra Club are laying out a road map to reach that "half Earth" goal, demanding that governments protect 30 percent of landscapes and seascapes by 2030.

To achieve this "30 x 30" goal will require new creativity on the part of the environmental movement—a combination of sparing lands and sharing them with other species. Some places will need to be spared from human domination via the kinds of parks and reserves that conservationists have traditionally focused on. Other places will need to be shared—that is, managed to accommodate both humans and other species. That could mean simply designating certain areas as off-limits to industrial development; putting private lands into permanent conservancies; or managing lands with local stakeholders, including Native American nations, that are committed to the sustainable use of natural resources. The all-important goal is to ensure that how we manage landscapes is part of the solution to both the climate crisis and the extinction emergency—not a contributor to them.

The real ecology lesson here? Protecting natural places is more than just good for the planet—it's the key to our future.

This article appeared in the September/October 2019 edition with the headline "Getting Back to Ecology."

Illustration by Karla Sanders