Ask Andrew Guzman, a professor of international law at U.C. Berkeley, why he decided to write a book about climate change, and he says it’s simple: It’s the biggest issue of our time.

“If I didn’t write about it,” he says, “for my grandkids, I’d sound like somebody who wasn’t interested in Nazi Germany in 1939.”

Guzman doesn’t want to be painted as an alarmist. That’s why, for the book, Overheated: The Human Cost of Climate Change, he assumes that we will see a modest (and increasingly optimistic) 2 degrees C of warming. You know, so as to stay on the conservative side of things.

But it turns out that 2 degrees is enough to sound some serious fucking alarm bells.

Guzman’s main goal, he says, was to look at the social, economic, and political costs of global warming. Most books focus on physical and environmental changes. Guzman wanted to examine human consequences.

Guzman spends a significant portion of Overheated exploring how troubled parts of the world will be affected by food and water scarcity vis-à-vis climate change. But some of the scarier parts of the book are about the overabundance of water that’s coming our way: 2 degrees warming probably equates to about a one-meter rise in sea level this century. That’s enough to displace hundreds of thousands to millions of people in low-lying nations, and, as of now, there is no plan to deal with environmental refugees.

“I think the question is whether the exit will be orderly or emergency crisis,” Guzman says. “If a storm comes at the wrong time and the international community is then plucking these people out of the sea, it’ll be horrible.”

The environmental-refugee problem becomes eye-poppingly scary when you look at the 150 million people living in Bangladesh. A one-meter sea level rise would swamp about 17 percent of the country.

“We know where people go when they lose their land: They go to cities, and they go to refugee camps,” Guzman says. “So the Bangladeshi cities that remain are going to be overrun and crumbling. Just think of the sewage system alone.”

Lest you think no one has considered what might happen next, in recent years India has increased security along the border with Bangladesh. “But fences are only so good up to a point,” Guzman says. “So how much violence are you prepared to use to keep that border secure? It’s not at all clear to me that the border can remain intact.”

Global warming is often couched as an environmental problem, but for Guzman, this misses the point. He’s skeptical that drowning polar bears and acidified coral reefs will mobilize the public into action. He’s a realist appealing to self-interested Americans. This isn’t about hugging trees and saving whales. This is about international security, global pandemics, terrorism — and a moral imperative.

Overheated is a fascinating read in part because Guzman goes out of his way not to be hyperbolic. But if you buy his book as you’re boarding a plane, it’s more likely than not that you’ll land feeling alarmed.

Listen in as I talk to Guzman about how he got involved with this topic, the chances that we’ll be able to avert disaster — and what we’re in for, as a species, if we fail to react in time.

This interview is part of the Generation Anthropocene project, in which Stanford students partake in an inter-generational dialogue with scholars about living in an age when humans have become a major force shaping our world.

Environmentalists and green marketers are always talking about “saving the planet.” Buy this car, this laundry detergent, or this light bulb and you will help save “the planet” or “nature” or “the environment.” Jenny Price, for one, wishes they’d stop.

Price is an activist, historian, and self-appointed Los Angeles urban ranger. When she’s not trying to inject a little humor into the generally unfunny world of environmental preaching with her satiric blog Green Me Up, JJ, she gives tours of the concretized L.A. River. She’d be happy to tell you why she loves the river, why it is every bit a part and parcel of “nature,” and why she thinks that places like this have got to be at the core of the environmental movement.

When it comes to rhetoric about “saving the planet,” she has two main beefs: First, it encourages a “greener-than-thou” form of preachy consumerism that does not encourage real change nor help those most in need. Second, the rhetoric clings desperately to the historical notion that nature = pristine wilderness, obscuring the muddy, mixed up reality visible in places like her beloved L.A. River.

Price, who calls herself a “lapsed wilderness-loving environmentalist,” doesn’t think we should stop caring about how sustainable our consumption is, but she does believe that we need to inhabit nature instead of trying to save it. We need to think a lot more about people, she says, and about creating communities and providing food and jobs both sustainably and equitably. In short, we need to deal with the real world.

We sat down with Price recently to talk about her street-level view of environmentalism, and how we can create a new movement that transcends class and socioeconomic divides.

This interview is part of the Generation Anthropocene project, in which Stanford students partake in an inter-generational dialogue with scholars about living in an age when humans have become a major force shaping our world.

The Anthropocene is more than just a fanciful notion held by those who believe homo sapiens has gone totally berserk. Bigwig geologists are taking the idea super seriously. In fact, members of the International Commission on Stratigraphy — the masters of the official geologic timetable — have organized a group of scientists and experts to consider formal adoption of the Anthropocene. The basic task of the Anthropocene Working Group is to try to imagine what the rock record will look like a million years in the future, and to figure out whether we humans will have a lasting enough impact to truly merit an epoch all our own.

To get a peek behind the curtain, the Generation Anthropocene producers recently sat down with four members of the Anthropocene Working Group: Jan Zalasiewicz, the group’s convener; Mike Ellis, head of climate change science at the British Geological Survey; Mark Williams, a paleobiologist at the University of Leicester; and Davor Vidas, an international lawyer and expert on the Law of the Sea.

“The signal — physically, biologically, chemically — will be quite clear,” Zalasiewicz said. “Unless the cavalry ride in, there will almost certainly be climate change on the order of 3-7 degrees globally over the next few centuries. There will be a major sea level rise … Beaches will be covered by offshore muds.”

Ellis added that submerged cities will be preserved for the ages as well: Rising sea levels “will fossilize the various urban structures that we have built over the past few hundred years.”

So those future geologists will see our signs. Now it’s up to Zalasiewicz, Ellis, and Co. to decide whether or not it’s hubristic and premature to say that we’ve kicked off a whole new geologic era. The team will make an official recommendation in 2016.

In the meantime, some members of the working group are concerned with the less academic implications of what we’re doing to the planet. Take Vidas, the lawyer. Rising sea levels will force a serious rethinking of maritime law, he said. “Our international law is the law of the Holocene. However, with the entry into the Anthropocene, with conditions that are not environmentally stable, we may be facing a problem.”

Every geologic boundary marks a redefinition of the terms of life on Earth, which is why the Anthropocene debate has that rare quality of being simultaneously academic and socially relevant. It is an exercise of deep-time imagination, but with real-world, right-now implications. So strap on your geology goggles and dive into the Anthropocene with the masters of the geologic timetable — for the 50th episode of Generation Anthropocene.

This interview is part of the Generation Anthropocene project, in which Stanford students partake in an inter-generational dialogue with scholars about living in an age when humans have become a major force shaping our world.

We’ve heard it 38,942,038,417 times* before: The system we use to produce meat in the U.S. is really eff-ed up. Feedlots = horror movies, all this carnivory is making us fat, and to make matters worse, meat consumption contributes to climate change. Right, all good arguments for eating less meat.

What we rarely hear is a fair, honest conversation with the actual farmers raising the animals that produce the meat that most of America consumes. That’s what Graham Meriwether wanted to do with his documentary, American Meat. The film explores meat production from the farmer’s perspective — and not just those who do it the free-range, organic, grass-fed way.

Meriwether initially set out to make a movie just about the alternative farms springing up across the country. He started off by talking to Joel Salatin of Polyface Farm, made famous by Michael Pollan’s book The Omnivore’s Dilemma. But when he started using stock footage of slaughterhouses, something didn’t feel right.

“I think the most important decision we made in the production of the film was not to put any hidden camera footage in the film,” Meriwether says, “because then that set us off on a journey where we got to talk to [conventional farmers], the people that, for the most part, feed most of our country.”

In the end, he was able to get his own footage of what goes on inside a slaughterhouse, but he chose not to include it in the film. We’ve become so distanced from the reality of where our meat comes from, he says, that we just aren’t ready for it.

Since Grist last spoke with Meriwether, he has continued his nationwide tour with the film, sparking mostly civil dialogs that inspire people to take a good, long look at what’s on the end of their fork.

In this interview, we talk about slaughterhouse scenes, how farming doesn’t have to be a full-time job, and why he believes we can have a sustainable meat system in the U.S. — provided we get 4 million animal farmers involved. As a bonus, if you listen to the end, you’ll hear about the one time one of his post-screening discussions blew up on him, and his (related) thoughts on veganism.

This interview is part of the Generation Anthropocene project, in which Stanford students partake in an inter-generational dialogue with scholars about living in an age when humans have become a major force shaping our world.

*Author’s estimate.

Improbable as it may seem, when Hayhoe, an atmospheric scientist at Texas Tech, married Andrew Farley, a linguistic professor and evangelical preacher, he didn’t know what she studied. And she didn’t know that he was a climate skeptic. Love, as a wise guy once said, is blind.

Over the succeeding years, Hayhoe and Farley debated the evidence, and, eventually, they proved the ancient proverb: In marriage, the woman is always right. Their experience even spawned a book geared toward evangelical Christians — A Climate for Change: Global Warming Facts for Faith-based Decisions — and something of a secondary career track for Hayhoe: communicating climate science to churchgoers.

When speaking at churches, Hayhoe often uses a chart of atmospheric CO2 that only goes back 6,000 years. She skims over little things like the age of the Earth and the process of evolution. Why? “To understand the reality of climate change, we don’t have to think the world is any older than 300 years,” she says. And besides, we don’t have the luxury of waiting to act on climate change until everyone is on the same page about everything.

So Hayhoe combines her scientific knowledge with an appeal toward people’s core values, whether they’re religious or not. It’s a welcome departure from the typical scientist’s approach of “beating-them-over-the-head-with-facts.” And it’s an approach that works well in rooms full of climate skeptics, as well as in marriage.

In this interview, we discuss the intersection of religion and climate science, whether Adam and Eve started the Anthropocene, and how to turn your budding romance into an opportunity to evangelize about climate change.

This interview is part of the Generation Anthropocene project, in which Stanford students partake in an inter-generational dialogue with scholars about living in an age when humans have become a major force shaping our world.

Imagine Earth with toxic air, stifling heat, no water, and no signs of life — sort of like Los Angeles. This is a world laid bare by massive and catastrophic climate change, and believe it or not, it isn’t science fiction. It’s our neighbor, Venus, and it’s more similar to Earth than you might want to believe.

Venus and Earth have a lot in common: They’re practically the same size, they’re made up of basically the same stuff, and early in the life of our solar system they were nearly identical, right down to oceans and moderate atmospheres. But then climate change arrived on Venus — the same processes that are playing out on our planet today with rising carbon dioxide and an increasing greenhouse effect — and transformed the planet into an uninhabitable, 900-degree-F wasteland swathed in clouds of sulfuric acid.

“It’s almost as if you had a twin study — you take these identical twins and give them different experiences in life and see how they grow up,” says David Grinspoon, an astrobiologist with the Denver Museum of Nature & Science and the NASA-sponsored astrobiology chair at the Library of Congress’s John W. Kluge Center.

Comparing planets and their evolutions is Grinspoon’s bread and butter, and Venus is one of his favorite subjects. “It gives us a laboratory to see if we really understand atmosphere and climate as well as we think we do,” he says. After all, physics is physics everywhere and chemistry is chemistry everywhere. So if our climate models on Earth are any good, we should be able to tweak the inputs and run them on Venus too.

Clearly we’re in no real danger of turning Earth into Venus anytime soon. But Grinspoon says that Venus is a sort of parable for what might happen if we keep pushing our climate system farther and farther out of balance.

Listen to my interview with Grinspoon below — and lest you think it’s all about climate apocalypse, we also took some time to discuss George Carlin’s philosophy of environmentalism, the “canals” on Mars, and Grinspoon’s old friend Carl Sagan.

This interview is part of the Generation Anthropocene project, in which Stanford students partake in an inter-generational dialogue with scholars about living in an age when humans have become a major force shaping our world.

When the Voyager spacecraft left Earth in 1977, it carried music in case it was ever encountered by aliens. If extraterrestrial beings have found it and downloaded its contents onto their iPods, they’re now listening to Mozart, Beethoven, and Chuck Berry, among others. When the Curiosity rover landed on Mars earlier this year, it beamed back will.i.am — and imagine, some people actually question our technological advances!

So what, exactly, is Curiosity doing out there? And what have we found so far? I recently sat down with Ken Herkenhoff, a planetary geologist for the U.S. Geological Survey and co-leader of the ChemCam team for Curiosity. ChemCam is that piece of technology that lasers rocks so we can learn what they’re made of. I talked with Herkenhoff about the rover itself, the gadgets on board, and the dicey “seven minutes of terror” involving the rocket-powered “sky crane” that lowered the rover to the Martian surface.

Now that we’re there, Herkenhoff explains that, “it looks like we landed in the outer parts of an alluvial fan” — confirming longstanding suspicions that there was once an abundance of water on Mars. But this finding is just the beginning of what Curiosity might accomplish. Two weeks ago, one of the mission’s principle investigators, John Grotzinger, told NPR the rover had found something “for the history books,” but refused to elaborate until the team had a chance to check its findings.

For those who feel horribly teased (NASA has promised more information in December), Herkenhoff offers his own list of potential “touchdown” discoveries, including ocean beds and organics — the carbon-based building blocks of life. We also spent some time talking about the rover’s cultural impact and why the team at NASA and the USGS call Curiosity “she.” So suit up and have a listen!

This interview is part of the Generation Anthropocene project, in which Stanford students partake in an inter-generational dialogue with scholars about living in an age when humans have become a major force shaping our world.

Imagine for a moment that planet Earth isn’t running out of anything. We have plenty of food, plenty of oil, plenty of rare minerals, and plenty of air. In this little utopia, the only constraint is space. We can breed like bunnies, and everything is fine — until we hit what I call Peak Elbowroom.

This is more or less the idea behind a series of experiments conducted by John B. Calhoun in the 1960s. Calhoun offered a group of rats a limitless supply of food, water, bedding, and everything else healthy, happy rats could want — except space. He kept his rats confined in “rat cities” — elaborately partitioned boxes designed to simulate the urban environment, which he built in his basement in Washington, D.C.

So what was the rat response? Turns out they all died. Well, they went big, then died. The population spiked and plummeted in a blaze of rodent self-extermination.

It wasn’t for lack of resources, obviously, but just from the sheer stress of it all. They were fat, happy, and multiplying. Then Peak Elbowroom hit, and then they went berserk, became anti-social, stopped breeding, and then … Poof. Gone. Completely extinct. Calhoun repeated the experiment several times, always with the same results.

Back in the ’60s, Calhoun saw his experiments as a metaphor for the human experiment — and who wouldn’t, right? After all, this was the decade of The Population Bomb, when scientists predicted the Earth was reaching its human-carrying capacity.

The human population didn’t crash, of course — at least it hasn’t yet. But last year, we soared past 7 billion people on the planet, and talk of the Earth’s carrying capacity reared its head again. With that in mind, first-time filmmaker Mike Freedman decided to resurrect Calhoun’s rats. In his new documentary, Critical Mass, he tethers their story to our own oh-so-tricky subject of resource binging and population growth. Here’s the trailer:

Freedman doesn’t pretend that Calhoun’s rats are a direct analog for humans, but, he says, “We see ourselves in it instinctively. It’s a very human trait to anthropomorphize.” Nor is the film about population control. Instead, he says, his intention was “to open a conversation.”

Which is not to say Critical Mass is apolitical. It does, however, strive for the wide view of human self-organization. Throughout the film, an army of experts weigh in on head-spinning issues like poverty, urbanization, peak oil/water/food, and, of course, environmental degradation.

The result is a film that is well-crafted, provocative, and stark. Critical Mass raises important questions about how we choose to live on our limited planet. We strive for equality — or at least to provide every human with his or her basic needs. But that is becoming more and more difficult as we race towards Peak Elbowroom.

Check out my interview with Freedman, below. The young filmmaker is clearly honing in on the big questions of our day with intense focus and specificity. He’s also one hell of a conversationalist.

And if you like what you hear, Freedman and his team are in the midst of a fundraising campaign to distribute the film. Learn more at the Critical Mass homepage or on Indiegogo.

This interview is part of the Generation Anthropocene project, in which Stanford students partake in an inter-generational dialogue with scholars about living in an age when humans have become a major force shaping our world.

Twenty years ago, scientists atop the Greenland ice sheet pulled up an ice core that both excited their curiosity and scared the pants off of them. They had discovered definitive evidence that Earth’s climate can change quickly, dramatically, and unpredictably, rearranging the planet’s energy balance and plunging Europe and North American into bitter, 1,000-year cold snaps. It wasn’t quite like they played it in The Day After Tomorrow, but it was damn scary nonetheless.

Though there is now ample evidence that our planet has seen dozens of these sudden climatic changes, the Intergovernmental Panel on Climate Change — the official, consensus-building arbiter of climate science — rates the probability of humans causing another abrupt climate change in the next century as low: less than 10 percent. Still, a one-in-10 chance of pushing the climate over a cliff is enough to sober you up. Should we be as scared as those scientists were?

“The science says that this is not yet screaming-hairy-panic-conniption-fit-let’s-run-for-the-hills-tearing-our-hair-out,” says our ever-quotable guest on this edition of Generation Anthropocene.

Richard Alley, a professor in the Department of Geosciences at Pennsylvania State University, was one of the key scientists who first realized the portentous message cradled in the Greenland ice core. While he agrees with the IPCC’s rating — he contributed to the most recent report — he thinks the longer we wait to wean ourselves from fossil fuels, the more we load the climatic dice. Every gigaton of CO2 we inject into the air just brings us closer to the possibility of a truly dramatic shift in climate.

Since that fateful discovery in Greenland, Alley has continued to focus his efforts on how our world’s ice sheets (collectively termed the cryosphere) will respond to climate change, but he’s also reached out, regularly testifying before Congress about climate change, participating in the PBS documentary Earth: The Operator’s Manual about humanity’s energy use, and even writing several geo-songs for his well-played guitar.

Despite discovering perhaps the most frightening aspect of Earth’s climate, Alley exudes an infectious optimism that humans can not only avoid abrupt climate change, but also improve everyone’s lives in the process. As he says, “Are we adding up enough good things and knowledge to outweigh the harm? Our ancestors did, and we’re here having this conversation because they did.”

Let’s hope Alley is right. His version of humanity’s future is far more pleasant than The Day After Tomorrow.

Listen in as we discuss climatological tipping points, who will pay most dearly as the climate changes, and why it’s perfectly justifiable to look at the evidence and say, “Aaaaaaah! Panic!”

This interview is part of the Generation Anthropocene project, in which Stanford students partake in an inter-generational dialogue with scholars about living in an age when humans have become a major force shaping our world.

We know what ecological degradation looks like: Clearcut hillsides, vanishing elephants and whales, forests overtaken with kudzu, and Florida swamps filled with Burmese pythons. These constitute a poignant, convenient visual shorthand for landscapes out of balance — so convenient, in fact, that it’s easy to forget about the ecological communities we can’t see.

What is the clearcutting equivalent for bacteria? How does the changing environment look to a virus? In other words, what is the disease landscape of the Anthropocene?

Obviously, any answer is going to involve some guesswork, but let’s look at the United States as a case study:

• Warming temperatures mean mosquito-borne diseases like malaria, yellow fever, dengue, and West Nile start moving north from the tropics.

• The explosion of rodent populations following the extermination of top predators across the U.S. contributes to the emergence of rodent-associated illnesses such as hantavirus and the new “Heartland” virus.

• Increased human travel and migration introduce new illnesses like Chagas disease, a tropical parasite that already affects an estimated 300,000 Latin American immigrants in the U.S., while helping turn local outbreaks into full-blown epidemics.

And these examples are just the tip of the parasite-ridden iceberg.

Frankly, it’s easy to get apocalyptic when it comes to emerging infectious diseases. James Holland Jones, a Stanford University anthropology professor and disease ecologist, says climate change will be a “mixed bag” for infectious disease. But when I asked him to sum up his prognosis for the future, he did so in a single word: “bleak.”

That’s partly because, as Jones points out in this interview, climate change and emerging diseases have something in common: The worst possible scenario seems far off and abstract, but fighting them requires diligence and resources right now.

Jones has studied everything from human sexual networks to plague outbreaks in prairie dogs to simian AIDS, and he’s aware of the difficulties global health agencies face in monitoring and controlling an emerging epidemic. His take-home message: If the landscape of disease is changing, our health infrastructure is going to have to change, too. Hemorrhagic fever doomsday hopefully not included.

This interview is part of the Generation Anthropocene project, in which Stanford students partake in an inter-generational dialogue with scholars about living in an age when humans have become a major force shaping our world.