No matter how sure you are that global warming is a real and pressing problem, it’s still hard to see it in front of you. Most climate change planning is based on hypotheticals: computer models that attempt to simulate how sea-level rise will change the land; simulations that play out damage from a serious storm. But because the climate can change so slowly compared to the average human life, it’s hard to grasp the evidence until it’s too late.
But there’s another way to tell the future, and that’s by looking at the past. Paleoecologists use fossils from hundreds of thousands of years ago to deduce not only what the climate was like, but also how the local landscape changed when, say, a major ice age began or ended. UC Berkeley paleoecologist Anthony Barnosky started studying fossils in the Rocky Mountains in the 1980s because he liked being outside and wanted to do fieldwork, but he soon realized he had stumbled upon something much more significant. “There’s a lot that the fossil record actually has to tell us about how what ‘normal’ really means in terms of nature,” he says. “How far are we off of that normal baseline? Are we off of it at all? And if we are, how do we fix it for the future?”
Barnosky recently published Heatstroke, a book examining through the lens of the fossil record what effects climate change will have on major mammal species. Perhaps more importantly, he addresses how quickly those changes might happen, and how our own ideas of conservation and protection of wildlife will have to change as a result. If we want wilderness, says Barnosky, we’re going to have to accept that the climate will change what it looks like—and that means letting some species die out.
Right now, that idea is heresy—how many millions have been spent to protect the giant panda? But Barnosky thinks that preserving undeveloped spaces, and the complete ecosystems within them, is more important to our sense of life on earth than keeping completely human-dependent animals alive. Which isn’t to say he doesn’t want to preserve biodiversity—he’s got some ideas for that, too—only that we have to think about it differently. I spoke with Anthony Barnosky in late July about the idea of wilderness, telling our fortune with fossils, and how to be a responsible environmentalist in the 21st century.
What convinced you that studying the fossil record is key to understanding current climate change?
I was doing grad work at the University of Washington, and at the time there was a big debate about whether direct pressures by people or natural climate change had caused the extinctions at the end of the last ice age, about 11,500 years ago. Since about 2.6 million years ago, there have been about 39 cycles of glacier growth (an ice age or glacial time) and retreat (an interglacial, as we are in now). For at least the last million years, each glacial-interglacial cycle has lasted about 100,000 years ago, with the glacial part of the cycle longer than the interglacial. Around 11,500 years ago, we came out of the last ice age, and into our present interglacial.
During my grad work, I happened upon a fossil site in the Colorado Rocky Mountains, which had a really, really
good sample of communities of mammals that lived during both glacial and interglacial times, long before humans even evolved. It was a really nice natural experiment: What are the effects of climate change if you take humans out of the picture?
The big thing we found by studying that site, after twenty years of work with a huge team of scientists, is that natural climate change seems to affect ecosystems from the bottom up. Normally you see changes in rodent- and rabbit-sized things, or changes in abundance, minor replacements of species. But really not much happens to the big guys, the megafauna. The difference between that and what humans are doing today is that we’re affecting the top end of ecosystems, through direct pressures like hunting and poaching as well as habitat fragmentation. The pace and magnitude of the current climate change means we’re even seeing climatic effects on larger species. The top carnivores and predators are being affected as well as the bottom ones.
Can you give some examples of where we might see this?
The classic example is something like polar bears, which are just disappearing off the face of the Earth. There are other, more subtle examples. In South Africa, where you see many of the large herbivores, big antelope things with spectacular curvy horns and so on, many of those species are actually being pushed out of various African national parks because they’re getting too dry in the dry season. When those animals go, larger carnivores that rely on them for food are going to go too. So you get this cascading effect. There’s the direct effect, like polar bears, then the indirect cascading relationships that end up causing a lot of things to go extinct.
Something I think it’s hard for people to get their minds around is how a loss of biodiversity will directly affect their lives. They hear about some beetle going extinct and can’t really figure out why that’s a catastrophe. Can you articulate
what we will lose, and why we should care?
There are really three reasons. One of them is a very practical reason, which is that it turns out we rely on other species in ways that people just don’t even think about. And without them, human life would be much poorer. A great example is the drugs we use, say, high blood pressure medicine that hundreds of thousands of people use. One comes from a very poisonous snake in South America called the fer-de-lance. It’s the only source of this drug Captopril, a common high blood pressure medication. That’s the only way to get it. The whole pharmaceutical industry has teams of people bioprospecting in remote parts of the world. There’s a fairly large percentage of pharmaceuticals that are derived from wild species. Talk about effects that would result from destroying most of the Amazon: You get rid of a lot of potentially life-saving drugs.
A more subtle example of this is that natural vegetation filters water in a way that’s economically more advantageous than building a filtration plant. So the city of New York buys property in rural areas as the cheapest way to provide water to Manhattan. It’s another example of “ecosystem services.”
Another reason is the moral obligation that some people would speak to, that we share the Earth with other species. And I think there’s a lot to be said for that. And then the third reason I think is that the human species
has evolved with these other species, and we like places with biodiversity. We get something back from it aesthetically, which I think ultimately is the reason most nature preserves exist. We’re a poorer world for not having them.
What does responsible environmentalism look like in the 21st century? How do we have to reenvision our ideas?
The way we’ve tried to preserve species isn’t going to work any more. Trying to keep the place they live in as a protected habitat is reasonably effective, but climate change is now so fast that those protective nature areas are really just islands. As soon as you pull the climatic rug out from under that species, the animals have no way to get from the island they’re on to the island that may have a more suitable climate.
If a wildlife reserve isn’t practical, what are other options?
People are talking about assisted migration, which is what happens now with some species of butterflies. So, species X is going to go extinct in a particular place, but look, eighty miles north the climate is still suitable. Let’s take some representatives of that species and move them to the new place. If we do that, we will be moving species around in order to save them. And that’s great for saving biodiversity if it’s done right. But the flip side of that is that an important aspect of preserving wildlife is preserving the feeling of being in a place that’s undisturbed by humans. And as soon as we start moving species all over, we’re in danger of losing those places. The recommendation I make in the book is to shift our philosophy so we think in terms of two kinds of conservation: one with the express purpose of preserving biodiversity, something like assisted migration; the other, a hands-off philosophy that would let nature take its course with new climate and see what happens.
The wildlands reserves would be places where we do not under any circumstances import any species. And the climate is going to change, so we’re going to lose, in some cases, many of the species that are in there. But it’s important to have those kinds of control plots on nature. We need places where you can still experience the feeling of nature without humans interfering.
For example, one of the world’s most spectacular areas of biodiversity is the Tambopata wildlife preserve on the border of Peru and Bolivia. It’s right on the edge of the Amazon, and climatic models predict that it has a high likelihood of changing from rainforest to savannah. One way you can look at that is to say, well, it’s going to disappear anyway, so let’s get logging trucks in there and make lots of money. Another way to look at it is to say, this place is pristine. Let’s watch it change into a new kind of pristine.
I understand this idea of preserving a feeling of wilderness for people to enjoy. But realistically, a place that’s going to change from rainforest to savannah thanks to human action doesn’t really seem like a wilderness. It seems more like a petri dish.
“Wilderness” is a moving target in terms of specifics. If you define it in a way where people haven’t affected it at all, well, there’s no place on Earth. On the other hand, people have always been a part of nature and interacted with nature, part of wilderness and interacted with wilderness, so I don’t think we’re entirely separate from local ecosystems. There are still a lot of places on Earth where there aren’t too many people—close to half the terrestrial landscape, in fact. And there are places that, if you go to them, you feel like you’re in a landscape that isn’t overrun by people.
That’s the feeling that I think needs to be preserved. There’s a quote from Wallace Stegner in my book: “Better
a wounded wilderness than nothing at all.” I tend to dismiss arguments that say there is no nature, there is no wilderness left. Give me one of those people and let me take them to the backcountry of Yellowstone Park and leave them for a week, then see if they tell me there’s no more nature.
Which specific species should we try to preserve?
There are certain species called keystone species whose disappearance would have dramatic effects on the rest of the ecosystem. Elephants are a good example of that. If they go, open woodland turns to closed forest, and there’s a whole cascade of things that go along with that. Secondly, you want to maintain diversity in the sense that, if you have two equally threatened species, one of which has a whole bunch of closely related species, the other of which is the only such species in the genus, of course you’d want to preserve that one.
What about California natives?
It’s difficult to say exactly. What we do know is projecting where the climate that supports certain species
will actually be in ninety years indicates that neither the California state tree (California redwood) nor the California state bird (California Valley Quail) will be able to live in California. For keystone species a bit farther afield, a good example is the whitebark pine, which is being severely reduced in Yellowstone Park due to a combination of warming winter temperatures and infestations of pine beetles and blister rust (the pine beetles are moving in because winter temperatures are no longer cold enough to kill them). Whitebark pine cones provide a critical food resource to sustain grizzly bears during certain parts of the year when other food resources are scarce. The grizzlies raid the caches of whitebark pine nuts that red squirrels have accumulated to help them make it through the lean times. Thus disappearance of whitebark pine is likely to cause reductions in both red squirrels and grizzlies.
It seems like a stroke of good luck that many “keystone species” are the sorts of animals that play well on calendars.
It is true that in a lot of cases the keystone species align with so-called “charismatic species,” because they’re often the top carnivores. If you take out the top carnivores, you immediately have increasing herbivore populations. The reintroduction
of wolves into the ecosystem of Yellowstone National Park has brought down elk populations and allowed aspen and willow to regenerate, really increased the diversity of life there.
Do you think humans are going to come around to these ideas, and do what is necessary to preserve not only our ability to live on the Earth but our sense of it as a place?
I have good days and bad days on that. Overall, I’m optimistic in the sense that when the human race recognizes a big problem, we seem to be pretty good at dealing with it. The state we’re at right now is not having recognized that we have a big problem. Still, if you think about awareness of global warming now versus ten years ago, there have been huge strides. It’s kind of a race against time. I think that if we get people thinking about this and recognizing what the problems are, we have a good chance of fixing it. But it’s not going to happen without governmental involvement, and it’s not going to happen without
a grassroots movement. We have to be working at it from both the top and the bottom.
Is there anyone out there now doing work you think others should emulate?
There are some very interesting initiatives going on now. One that’s been around for a long time is a group called the Yukon to Yellowstone Initiative, which has the goal of maintaining migration corridors between all natural areas in the Rocky Mountains. That’s one strategy that is going to be very helpful. I think Patagonia has just launched an initiative, maybe about a year old, where they’re doing similar sorts of things where there are still some semblance of natural landscapes
and trying to connect them by corridors. But of course now we have to think about overlaying projections about climate
on those corridors to make sure the species we want to preserve are going to have climate to move to.
There’s also an idea called win-win ecology, which focuses on preserving biodiversity by doing some fairly simple things like planting native vegetation in your yard instead of lawn. It’s one example of how we can actually design our living spaces and human-intensive landscapes to maximize habitats for other species as well. Those strategies are part of the picture. The ecosystem services angle is also going to be very important in terms of putting values on these services we get from different species. It has to be a whole cluster of strategies.
