After years of photographing the world’s most exquisite natural spots, you’d think Gary Braasch would be despondent or furious or even numb about growing signs of climate change. But he’s actually determined. Determined to keep documenting the evidence firsthand — as he has for the past 10 years — in the clearest, most compelling way possible.

“It’s perfectly sad and sometimes I feel angry,” he says, rubbing his beard, eyes flashing, as we stand in the sunny atrium of the American Association for the Advancement of Science (AAAS) headquarters in Washington, D.C. “But I try to translate it into determination — make stronger and stronger connections between what I’m seeing and what scientists are telling us and maybe help people better understand that nature is a precious thing that we’re damaging at our own peril.”

It’s early November and Braasch, who lives in Portland, Ore., is in Washington, D.C., setting up an exhibit of climate-change photos from his newly updated book Earth Under Fire: How Global Warming is Changing the World. The exhibit (on display through April 30) is designed to coincide with continued climate discussions, including the Senate climate-bill debate.

Braasch’s determination is unmistakable. I see it in the way he keeps driving home his points — despite the fact that we have to continually move out of the way of workers who are hanging photos and talk over the sound of hammering and drilling. I see it in his calm certainty that the exhibit will open on schedule the next day — even though someone has inadvertently made off with the yet-to-be-hung captions, and photos for an accompanying exhibit (from a children’s book Braasch co-wrote with Lynne Cherry called How We Know What We Know About Our Changing Climate: Scientists and Kids Explore Global Warming have yet to arrive.

Braasch keeps talking in spite of it all, relentlessly and methodically laying out his case like a lecturing professor. He cites studies off the top of his head, motioning to various photos hanging along the atrium walls to illustrate his points — a before-and-after shot of the receding Athabasca Glacier in Alberta, Canada; shoreline erosion from rising sea levels on Cape Hatteras; and one of his favorites, a magnificent Antarctic ice cave that melted shortly after he photographed it in 2000.

“When you actually look at pictures of places that are changing and get facts about how fast it’s happening, I think it’s more believable — you sense it’s not being made up,” he says. “There’s a need for more convincing explanations about what’s happening.”

It’s the same approach he uses in Earth Under Fire — relentlessly and methodically blending pictures and facts to document not only the physical impacts of climate change but also impressive evidence that it’s human-generated. Evidence that even a hardcore climate-change denier might be hard-pressed to dispute (at least in my mind).

“It’s hard for some people to believe,” he says, “but there are now thousands of scientific observations showing that climate change is very rapid and that the extra CO2 correlating to the amount of temperature change is the kind generated from burning fossil fuels. Add it up and you get a very strong scientific argument that there’s no alternative explanation.”

On the upside, Braasch is equally determined that humans are capable of cutting CO2 enough — and possess the necessary will — to avert a major catastrophe. “We’ll have to contend with the effects we’ve already put in place, but we can stop it from getting worse,” he explains. “It’s the right thing to do, and when people start getting that, I think there will be plenty of energy, money and certainly the technology.”

Indeed, Braasch’s book and exhibit present many technological “solutions” that already exist, such as Portland’s low-carbon mass-transit system. But the coming “revolution” won’t be easy, he concedes. Nor is there much room for compromise.

As he notes in the book’s epilogue, the best way forward requires that: “No policy … be promulgated, no program initiated, no alliance sealed, no purchase made, no machine designed or built, no land use permitted, no product introduced, no law passed, no politician elected unless the action is a step forward to reduction and reversal of the effect of greenhouse gases.”

A tall order, even for someone as determined as Braasch.