Environmental art is hard to peg down; its definition is as uncertain as the future of the environment. Just as one person's reusable grocery bag is another's mass transit, one person's mammoth (often destructive) land art is another's recycled art materials. Katherine Ware's Earth Now, a book she just released in concurrence with an exhibition of the same name she curates at the New Mexico Museum of Art, looks at environmentalism through its photography over the 20th and 21st century.

On the small end of coffee table books, the book presents 91 photographs with lush space between Ware's expositions. Ware's clear prose is more accessible than that of many art books, which can become mired in esoteric references and run-on sentences. Instead, she simply and clearly presents the photographers' works, as well as the underlying rationale.

The exhibition includes slightly fewer images, but adds multimedia elements, including a looped video by Santa Fean Bob Gaylor of the mesmerizing and mind-boggling Pacific Ocean garbage patch, as well as video interviews with some of the artists.

Both Earth Now iterations include 33 American photographers, seven of whom—Subhankar Banerjee, Michael P Berman, Christine Chin, Chris Enos, Greg Mac Gregor, Patrick Nagatani and Carlan Tapp—currently live in New Mexico.

Both the book and exhibition are divided into two loose sections: the dichotomous 20th century with its "Idealists, Skeptics and Doomsayers" and the 21st century's pragmatists in "Finding a Way Home."

According to Ware, art photography from the 20th century ran the gamut, from the "reverent" black-and-white naturescapes of Ansel Adams to the "critical" neon captures of toxic waste by Richard Misrach.

Nagatani is the only living New Mexico photographer included in the first section. His "Waste Isolation Pilot Plant Nuclear Crossroads," which uses large-print photography and hand-colored collage, depicts dead roadrunners in front of a city sign for Vaughn, NM.

Nagatani, who considers himself a "skeptic" and an "activist," creates humorous and apocalyptic works that often confront New Mexico's nuclear legacy.

"The medium can basically only [provide awareness]. For effecting change, it's one step past awareness, and that's protest," Nagatani says. "I think there's a certain limit to how potent the images can be."

Twenty-first century environmentalism seems more middle-of-the-road than the previous century, its commentary less polarizing and overt. In a substantially larger section (both the number and size of the works), artists approach photography from a wide range of angles, ethos and techniques.

Chris Enos uses a panoramic camera vertically to capture iconic outdoor scenes, including Arches National Park in Utah and a river in Ouray, Colo. She then paints over the photos and hangs them low on the wall to give the viewer a more intimate experience.

"I don't know that it effects change," Enos says of her work. "In the Renaissance perspective, we look at the world through a window. That window separates us from the world we are photographing," she says. "I'm really trying to get people to enter into space."

Though Enos claims to have no political agenda, she does concede that her photographs could have an indirect impact on the environment.

"If people were closer to nature, they wouldn't fuck up the world so bad," she says. "If they had chance to get into nature, connect to it more, they'd have more respect."

Subhankar Banerjee has, in a way, forced respect.

Banerjee is famed for his arctic photographs, which have affected government policy concerning those areas. For this exhibition, though, his works hit closer to home—in walking distance from his home in Eldorado, in fact.

Though his photos from Where I live, I Hope to Know include dead piñon, blighted by the bark beetle infestation, he is optimistic. He focuses on the dead trees as protective habitats for birds, while he maintains a keen awareness of why those trees originally died.

"While it happened as local issue, it's one of greatest issues happening globally," he says. "On both sides of highway or train, the land going to the distance; a lot would see it as wasteland to deal with a distant perspective. For me, I think of inhabited ecological space."

Banerjee hopes to "defamiliarize" the desert so that people can begin to "engage" it, and affect environmental policy as a result. "Art is a way to engage," he says.

Carlan Tapp sees photography as less active, more didactic—as a way to "draw awareness and educate." "If people don't understand that something is happening, they can't make a logical decision or choice," he says.

For seven years, Tapp focused his camera largely on Navajos living in the Four Corners area, where a third coal-burning power plant was slated to receive an $85 million tax credit in 2007. (The tax credit has since been rejected.)

Tapp considers himself a documentary photographer—"It can be very powerful if people tell their own stories," he says—and often combines the audio of his subjects along with their photos.

Not unlike what Earth Now does: It tells stories, with many different narratives and viewpoints. The environment is simply a prompt.

Both the book and exhibition have no aspirations as game-changers. Wall text at the back of the Museum of Art even confronts the entire exhibition's hypocrisy, explaining honestly the answer to "Is photography good for the environment?" (No, it isn't, but that's not the point.)

Earth Now provides a freeing framework in which to showcase several generations of American photographers. Its guidelines are loose to mirror—and not constrain—the tenuous bonds that hold together environmental art. Earth Now shows that environmental photography is varied—beautiful, ugly, inciting, etc.—just like the state of the environment and the ways to save it.

Earth Now
By Katherine Ware
Museum of New Mexico Press
188 pages
Through Aug. 28

New Mexico Museum of Art
107 W Palace Ave.
Peruse the collection online at nmartmuseum.org