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.

By now you’ve probably heard of the Anthropocene. Pin it on climate change, ocean acidification, mass extinction, resource depletion, global population, landscape transformation, or any other holy fuck hockey-stick graph: The point is that the stable environmental conditions of the Holocene -- the geologic epoch we've known and loved -- no longer apply.

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.

When Charles Darwin wrote, "Multiply, vary, let the strongest live and the weakest die," do you think he thought to himself, “Dude, I'm about to piss a bunch of people off”? Or when Copernicus and Galileo forwarded the idea that the Earth revolves around the sun, and not the other way around, do you think they were trying to ruffle Vatican feathers?

Well, OK, maybe these guys saw trouble brewing. But another, contemporary scientist didn't. In the mid-1990s, Benjamin Santer authored a chapter in a report of the Intergovernmental Panel on Climate Change that included this sentence: “The balance of evidence suggests a discernible human influence on global climate.”

Innocuous enough, right? But it would prove to be a pivotal moment for the discussion of global warming. Today, the political cacophony surrounding climate science is so loud that it drowns scientific reasoning like a Jack White solo at a Simon and Garfunkel concert. And much of the noise can be traced back to that sentence.

I recently sat down with Santer, a MacArthur Award-winning researcher at Lawrence Livermore National Laboratory, to get his firsthand account of the day the global warming show went from soft acoustic to power-blasting electric.

“I was blissfully unaware of what would happen at the end of 1995,” he told me. “The only thing I thought about was doing the best possible science and searching for that holy grail of objectivity.”

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.

Michael Shellenberger and Ted Nordhaus have a real knack for stirring the pot.

In 2004, the duo, founders of an Oakland, Calif.-based think tank called the Breakthrough Institute, published a paper called “The Death of Environmentalism: Global Warming Politics in a Post-Environmental World.” Much to the chagrin of many old-school greens, they argued that the institution of environmentalism was unable to deal with the global crises knocking at our door, because environmentalists were pigeonholed by what they called “the politics of limits” -- that is, enviros keep prophesying the End Times, only to be proven publicly and embarrassingly wrong. (Grist ran a whole series about the ensuing melee under the banner “Don’t Fear the Reapers.”)

There are 1,001 reasons to love the local/slow/organic food movement. Whether we care about animal rights, our carbon footprint, or the poverty-obesity link, it behooves all of us to take a serious look at our food choices. But before we get too carried away by the promise of small-scale, chemical-free growing, let’s look at some of the cold, hard facts:

• A billion people go to bed hungry every night, and another billion aren’t too far from that.
• We’re about to add another 2 billion people to the global population.
• The planet is warming (fast), meaning more heatwaves and drought, which is bad news for growing food.

Translation: It’s going to take more than backyard chicken coops and window-box gardens to get us through the next few decades.

In 2000, Nobel Prize-winning chemist Paul Crutzen suggested that humans have had such profound and far-reaching impacts on the planet that we have ushered in a new geologic age – the Age of Man, or, as Crutzen called it, the Anthropocene. The idea has been bouncing around the halls of academia ever since, and in the last few years, it has jumped from the ivory tower into popular literature and a few geek-tastic conversations over beer. The notion that humans now run this joint seems to have struck a chord.

Just getting up to speed? The team from the Generation Anthropocene podcast at Stanford University sat down in the recording studio and tried to explain everything in five short minutes. (It ended up taking seven, but who’s counting?) Just for fun, they did it game-show style.

The elusive axolotl. (Photo by John P. Clare.)

“Should we be like gods? Should we control the whole thing -- who gets food, what the weather is, where it will rain, what species get to live and die?”

-Susanne Moser, climate researcher, consultant, and Aldo Leopold fellow at the Stanford Woods Institute

About two months ago, the Generation Anthropocene radio team was invited to Santa Cruz for a conference for the Aldo Leopold Leadership program in environmental science. Leopold was one of the grand old dudes of the environmental movement, and you probably think that a program sporting his name screams “old white man reeking of patchouli.” But the conference was actually really cool.

Sure, there were plenty of old-school, save-nature-'cause-it's-really-neat conservationist types. But the Leopold fellows are world leaders in the environmental sciences. They’re smart as hell, if not a bit dorky. The Leopold program trains scientists to communicate their work with a broader audience, and its leaders are especially interested in catching the ear of the next generation.

As they put it, they’re tired of the “gray hairs” in the room. They want to know if we give a damn about climate change, mass extinction, and the global binge on natural resources.

Well, we wondered, why should we care?

Geologists are not particularly renowned for their conversational skills. They tend to be a hairy bunch of beer-drinking nerds who are probably the only people on the planet that still prefer Tevas to Chacos. But every now and then the earth sciences offer up an idea that reverberates and captures our attention.

Witness Charles Darwin. You may think of Darwin as a biologist, because he gave us an appreciation of the spectacular biodiversity of the planet. Geologists, however, claim his as their own: For evolution to work, you need a WHOLE lot of time. Darwin understood this. He’d studied geology.

More recently -- in the last couple of years, to be exact -- geologists have brought us another show-stopping concept. They call it the Anthropocene. Literally, anthropocene means “the age of humans.” We humans, the thinking goes, are a geologic event like asteroid impact or the end of an ice age.

At first this sounds like a joke. When you look at it through the long lens of earth history, our occurrence appears as an insignificant blip. We’re the last second on a 24-hour clock, the last inch before the end-zone on a football field. We’re nothing. We’re tiny. We’re a fraction of a percent, an evolutionary remainder.

But, if you think about it, there are, in fact, some very good reasons to think that we’ve created a new geologic age. We’ve certainly changed the terms of life. We killed off the woolly mammoth and the dodos, shipped pythons from Burma to Florida, and created breeding grounds for rats, raccoons, pigeons, and other urban-loving creatures. Throw climate change and ocean acidification into the mix, and it’s easy to make a case that our influence surges from continental to global. Even if a virus wipes us all out tomorrow, our impacts on the planet will be felt for a long time to come.