Back in the mid-1970s, Edward Abbey’s The Monkey Wrench Gang made Doug Peacock something of an icon of the new environmental movement — albeit a somewhat reluctant one. A writer and naturalist, Peacock says it has been difficult at times to live up to the expectations of people who still think of him as George Hayduke, the fictional ex-Green Beret and “wilderness avenger” of Abbey’s classic novel that he helped inspire.
 
But four decades later, Peacock is still in the fight, battling to protect both the western wilderness where he found solace after returning from the Vietnam War and the embattled grizzly bears that he says saved his life.
 
For his latest book, In the Shadow of the Sabertooth, Peacock digs into the distant past – about 15,000 years ago – to explore the last time human beings endured a major period of global warming. The lessons of that period, he says, still resonate today.
 
In an interview, Peacock explains what humankind has to learn from North America’s first human inhabitants, what it will take to save the natural world from modern threats, and why he believes Yellowstone’s grizzlies are facing their greatest threat yet.

Peacock will make two appearances at Yale next week.

Q: You’ve written about how climate change is changing the planet today, but your new book is about what happened the last time humans experienced rapid climate change — soon after they first populated North America. Why did you decide to write about this period?

PEACOCK: Well, global warming — and the collective damage we have done to Mother Earth and all the systems that support life on this planet — is the story of my time and my generation. We call it climate change, but more accurately it’s global warming. It’s also a really bummer story. The prognosis is so damn grim that I’m reluctant to say what I really think to high school students. And I didn’t want to write a bummer book. So I thought about how I could get around this in a not-totally-cowardly-yet-constructive way. So I asked myself, ‘Well, have humans beings ever gone through something like global warming before?’ And indeed they’ve experienced one global warming, which made a huge difference, and it was the one that happened right here in North America about 14,700 years ago. It was right after the last glacial maximum of the Pleistocene Era and the great glaciers of the late-Pleistocene began to melt and the oceans started to rise.

When these first humans set foot on this continent, they encountered all these amazing, huge animals here. The so-called Pleistocene megafauna: the mastodons, the mammoths, 6,000-pound sloths, 20-foot condors, a scavenging bear that stood about seven feet at the hip, about twice as big as the grizzly. The land was Eden, but also there were enough predators — including animals that humans had never met before — that it was probably a pretty formidable place to live.
 
But at the very end of this period of global warming, all of these animals go extinct. Some of them, it looks like, in a geologic second. And they disappear soon after the first successful colonizer of North America arrived — the big-game hunters we call Clovis culture.
 

Q: That sounds familiar.

Peacock: Yeah, what you get out of this is that this combination of global warming and human activity is a timeless, deadly formula for extinction. The comparisons are not totally obvious — they’re more parable than parallel most of the time… There are some things that happened that are similar to what’s happening now, like the amazing sea rise. But of course a planet with 7 billion people isn’t quite the same as 13,000 years ago with possibly a few thousand hunters sprinkled across all of North and South America.
 

Q: Beyond the impact these humans had on the continent’s wildlife, the changing environment took a real toll on the Clovis peoples, too. Why was that?

Peacock: It’s still a mystery. The obvious factor is that they ran out of things to hunt. The theory is that these people had come down the ice-free corridor and in Alberta they ran into their first mammoths. And their puny spears were just too small for this great big predator. But when they got to the first flint quarries, where they could experiment with their flaking techniques, they invented the first Clovis point, which were big enough to take a mammoth down. It was this iconic, signature weapon, around which a culture evolved and emerged. But it was very short lived and we don’t really know much about them, besides their tool kit. And it appears that Clovis just disappeared, not quite overnight, but certainly in a geologic second. Was it because they hunted all the mammoths out to extinction or because there were no mammoths left to hunt? It’s a snake eating its tail, and they just went down at the same time.
 

Q: What lessons can modern humans heed from this chapter?

Peacock: The most important thing is the perception of risk. I think the only hope for modern humans is if we are able to perceive global warming as the beast of our time. As dangerous and lethal as anything we’re evolved to see on the African savanna. As tough as those gigantic Pleistocene lions in North America or the gigantic short-faced bear. But we weren’t handed that kind of a brain. All of our evolution took place in habitats we call today wilderness and we really evolved to deal with the sabertooth in the bush. We didn’t evolve to worry and think about this impending danger that looks like its really incremental and distant — something that happens across the earth to starving strangers. It’s not quite the same thing as a child in danger, or a dark alley, or a real brush with modern-day death.
 
The most important value that I dragged through this book, I think, is that the best thing I can do is to help preserve wilderness. And that’s indeed what I do. It’s my full time job. I’m self-appointed, unsolicited and unpaid, but it’s what I do. I think it’s about as important as anything anybody can do.
 

Q: Seeing the value of the natural world — and the human connection to it — is something you wrote about in Grizzly Years [1990]. Do you feel like people are getting it more today?

Peacock: Well, a lot of people have gotten it. And it’s really gratifying to me that they have. But there are so many more of us all the time. There’s no way to keep pace with 7 billion people all wanting to live like Americans. There aren’t enough resources on earth for endless progress of any kind, whether it’s industrial, economical or any other sort.
 

Q: Many people came to know you through your writing about grizzly bears and your advocacy to protect them. What do you see as the greatest threat to grizzlies today?

Peacock: The biggest threat of all is global warming. I live 30 miles from Yellowstone, where we’re seeing one of the results of global warming — the pinebark beetle. With warming temperatures the beetle has moved up a couple thousand feet, and the whitebark pine tree nut — the major food for grizzlies in Yellowstone since white people showed up there — has been wiped out. It’s gone. Maybe 96 or 97 percent of all of these trees. It’s amazing. If you didn’t believe in global warming, all you hadn’t to do was look at the top of the mountain starting about 2007. The mountain turned red. And then you drive around Yellowstone, and at the tops of all the other mountain ranges, and everything above 7,600 feet is red. Those are dead whitebark pine trees.

And now the government wants to de-list the grizzly. The government may be the bear’s worst enemy. Saving them was always pretty simple: you protect the grizzly’s habitat and you don’t kill them. Because grizzly bears are extremely flexible, adaptive omnivores. But this is the biggest hit they’ve ever taken. When ecosystems warm up, the obvious response is for species to either move north or move up the mountain. Well, whitebark pine already occupied  the top of the mountaintop, so the bears can’t move up anymore. And grizzly bears are largely blocked — by human intolerance largely — from moving from one ecosystem to another. Yellowstone is a great big island, that’s all it is. And island populations tend to go extinct over time no matter what. Yellowstone’s grizzly bears are no different.
 
The minute the government de-lists the grizzly, the states of Wyoming, Montana, and Idaho will put out hunting permits. Wyoming has already proposed putting up 50 grizzly bear tags. If all the states did that it’s conceivable that grizzly bears could take a big enough hit from hunters in a season or two that they could be hopelessly on the decline forever. There are just a lot of bad things going on. So it’s the combination of global warming and bad politics. That’s what I’m fighting now.
 

Q: In Grizzly Years, you described how your life was transformed after spending time in the West after returning from the Vietnam War. What did that period mean to you and how has it shaped what you have done with your life in the years since?

Peacock:You know, in 1968, like a whole lot of other vets I came back from Vietnam kind of out of sorts. I couldn’t be around people. I was just no good. I was hyper alert, and I really didn’t want to be close to anybody. I’d grown up in the woods, and I’d sampled the Rocky Mountain wilderness before the war. I loved the empty, wild places of North America and I was quite comfortable camping out by myself. And so that’s what I did when I came back. I camped in the Rocky Mountains. I started out down in Arizona and Utah, and went up to Wind River Range and Yellowstone. And that’s where I ran into grizzlies. I wasn’t looking for them. But they were there.

When you’re living in the backcountry, especially alone, and with grizzly bears around, self-indulgence is utterly impossible. Because there is something out there that is dominant, powerful and that can kill and eat you any time it wants to. It doesn’t do it often, but it can. So that really gets you out of yourself. You don’t walk down a trail in grizzly country thinking about your bank account, your girlfriend, or your sports car. You hear better, you smell better. You listen to the birds a little differently. And you know, that’s exactly what I needed.
 
It didn’t happen all at once, but these animals riveted my attention month after month, and then year after year. I think I say someplace in Grizzly Years that these bears saved my life. And that’s pretty damn close to the truth. And when something like that happens to you, and if you live with these animals in the backcountry, your skills are fine enough that you can tell as much about grizzlies as anybody else. And I could tell by the early 1970s that the grizzlies in Yellowstone were in bad trouble. The populations were really crashing… So then it was payback time. And that’s when I decided that I had to publicize the plight of the grizzly.
 
I had never thought of myself as much of a writer, but I had a story to tell, and it was pretty easy to find a publisher — and I needed money. So I set out at a lookout in Glacier Park with a typewriter and carbon paper and banged out Grizzly Years. And it came out amazingly fast… It almost wrote itself, it was so easy to write. By the end of summer I’d completed about 75 or 80 percent, in about 2 ½ months.
 

Q: It sounds like the spirit was with you.

Peacock:Yeah, and I didn’t know I could do that, and I enjoyed it. I’d never taken a writing course. But I liked writing. It was easy because, as I said, I had a story to tell. And I was already an advocate for the wild. It also allowed me to make a living.

Q: During the Environmental Film Festival, here at Yale, you’ll be introducing a film called “DamNation.”

Peacock:It was actually made by two friends of mine. And from what I’ve seen of it, it’s about taking out dams. I’ll probably talk about the origins of dam removal, sometimes referred to as monkey-wrenching, which of course comes from Edward Abbey’s Monkey Wrench Gang [published in 1975]. Of course, me and Ed Abbey were hanging out pretty frequently back in those days. And he crudely modeled his main character, Hayduke, after me. So I’m sure I’ll talk a little bit about the history of the American militant environmental movement.
 
The spirit back then was militant civil disobedience. But it’s joyful civil disobedience. It doesn’t take itself too seriously. And yet it’s the Lord’s work, man. It needs to be done. Everyone needs to do it as much as possible.