David BrowerThe U.S. environmental movement faced a lot of peaks and valleys over the past century, but it gradually reached new heights thanks largely to one guide: California mountaineer David Brower (pictured at right). Born in Berkeley on July 1, 1912, Brower grew to love nature as a young climber exploring the West — and by the time he died in Berkeley eight decades later, his ecological enthusiasm had spread nationwide and bridged a generation gap from John Muir to Al Gore.

Brower didn't just help eco-minded Americans find their footing, though. With a distinctive mix of hope and anger, he also taught them how to dig in their heels. "Polite conservationists leave no mark," he once said, "save the scars upon the Earth that could have been prevented had they stood their ground."

July 1 marks his birthday, and while the irascible naturalist isn't around to enjoy it, the rest of us still have cause to celebrate. In honor of his centennial, here's a look back at some of Brower's biggest achievements and milestones:

1927: At the age of 15, Brower discovers a new species of butterfly — named Anthocaris sara reakirtii broweri in his honor. He later studies entomology at the University of California-Berkeley before ultimately dropping out of school.

1938: Five years after joining the Sierra Club under a sponsorship from nature photographer Ansel Adams, Brower joins his first conservation campaign — a successful effort to establish Kings Canyon National Park in California.

Kings Canyon National Park Kings Canyon National Park in California is in the southern part of the Sierra Nevada range. (Photo: Michael Vi/Shutterstock)

1939: Brower leads a historic first ascent of the Shiprock monadnock at the Navajo Reservation in New Mexico, one of 70 first ascents in his career.

Winter at the Shiprock monadnock in New Mexico Winter at the Shiprock monadnock in New Mexico. (Photo: Joe Frisino/Flickr)

1942-1945: Brower enlists in the U.S. Army's 10th Mountain Division during World War II, serving as a mountaineering guide for U.S. troops stationed in the Italian Alps.

1952-1969: After returning home from the war, Brower becomes the first executive director of the Sierra Club, helping its membership grow tenfold — from 7,000 to 70,000 — during his 17-year tenure.

1956: Brower leads an effort to block a proposed dam that would have flooded Dinosaur National Monument on the Upper Colorado River. (To succeed, however, he makes a deal that later comes back to haunt him.)

Whirlpool Canyon at Dinosaur National Monument Whirlpool Canyon at Dinosaur National Monument. (Photo: National Park Service)

1960: Brower helps create the Sierra Club Foundation, an independent charity that sponsors programs of the Sierra Club and other groups.

1963: Brower and the Sierra Club successfully push for the creation of California's 71,000-acre Point Reyes National Seashore.

Point Reyes National Seashore Point Reyes National Seashore is an expanse of protected coastline in California. (Photo: Xiu Yu Photography/Shutterstock)

1963: Construction of the Glen Canyon Dam in Arizona is completed. As part of his 1956 deal to block the dam at Dinosaur National Monument, Brower had agreed to support another dam and reservoir at the lesser-known Glen Canyon, which he had never visited. He quickly realized his mistake, though, writing in 1963 that "Glen Canyon died, and I was partly responsible for its needless death."

The Colorado River downstream from Glen Canyon Dam The Colorado River downstream from Glen Canyon Dam. (Photo: Christian Mehlführer/Wikimedia)

1964: After years of lobbying from Brower and many other activists, Congress passes the Wilderness Act, a major victory for the U.S. environmental movement.

1966: In an effort to stop proposed dams from being built in the Grand Canyon, the Brower-led Sierra Club buys full-page ads in major newspapers, one of which asks "Should we also flood the Sistine Chapel so tourists can get nearer the ceiling?" Later dubbed the "Grand Canyon Battle Ads," the campaign helps pioneer the practice of advocacy advertising. The dam proposals are shelved the following year.

1968: Pressure from Brower and the Sierra Club leads to the creation of Redwood National and State Parks and North Cascades National Park.

Sunrise through morning fog at Redwood National and State Parks. Sunrise through morning fog at Redwood National and State Parks. (Photo: Rick Sharloch/Flickr)

1969: Amid growing internal conflict at the Sierra Club — largely related to financial troubles under Brower's leadership, despite big membership gains — Brower steps down as executive director. Later the same year, he founds three new environmental groups: Friends of the Earth, the League of Conservation Voters and the John Muir Institute for Environmental Studies.

1972: The United Nations approves a new system of World Heritage Sites, an idea that had been proposed by Brower and other activists.

1982: Brower founds the Earth Island Institute in San Francisco.

1983: Fourteen years after leaving as executive director, Brower is elected to the Sierra Club's board of directors.

1986: Brower and other environmentalists succeed in their campaign to establish Great Basin National Park in Nevada.

night sky over great basin national park The Milky Way appears over Great Basin National Park. (Photo: Asif Islam/Shutterstock)

1987: A Senate committee hears testimony from Brower against proposed oil drilling off Alaska's North Slope. "If you borrow something with the intent on returning it or paying the loan back, that is ethical," he says at the hearing. "If you have no intent to pay it back, or can't, then it is a form of stealing, which is supposed to be illegal."

1990: A tuna boycott, spearheaded by Brower's Earth Island Institute, results in new "Dolphin Safe" product labels for canned tuna.

1996: Six years after Brower and the Earth Island Institute led their first delegation to Russia's Lake Baikal — where they sought ecological protections for the world's oldest and deepest lake — the U.N. names it a World Heritage Site.

1998: Brower is nominated for a Nobel Peace Prize, his third such honor.

1999: The first annual Brower Youth Awards are held in San Francisco, aiming to "raise the profile of young emerging environmental leaders in North America, celebrating their achievements, and providing them with the skills, resources, and relationships to lead effective campaigns and projects." Sixty-one of these awards, along with cash prizes, have been awarded in the 12 years since.

2000: Brower dies in Berkeley at the age of 88.

For more about Brower's life and legacy, read this excerpt from "The Wildness Within," a book about Brower by his son Kenneth. To hear Brower personally describe his philosophy on wilderness, check out "Wilderness Alps of Stehekin," a filmed he produced with his two sons in 1957:

Photo of David Brower: U.S. Fish and Wildlife Service

Russell McLendon ( @russmclendon ) writes about humans and other wildlife.

Happy birthday, David Brower
Born on July 1, Brower is still widely considered a pioneer of environmental activism. Here's a look at some of his lasting legacies.