Photo by Corrynn Cochran.

Florence Williams is a decorated environmental writer, one of my personal heroes (we launched our careers at the same ragtag Western environmental mag), and author of the new book Breasts: A Natural and Unnatural History. I caught up with her over a cup of coffee this week and learned a little about the biological theories of bustiness, the chemical cocktails that are showing up in breast milk, and a smartphone app that makes my childhood days of sneaking peeks at Playboy bunnies look positively pedestrian.

Q. Why write a book about breasts?

A. The idea occurred to me when I was breastfeeding. I hadn’t really thought about my breasts before that, but suddenly, I was totally wowed by them and what they were able to do. It’s totally amazing. And then of course I learned that there were toxins in breast milk, and so that really launched me down this path of trying to learn how modern life has changed breasts and how breasts evolved and why they’re so special to us to begin with.

Q. Why are human breasts so different from other mammals'?

Brittany Trilford.

If you had just a few minutes to address world leaders -- to give the ultimate “My Fellow Earthlings” speech -- what would you say? That was essentially the question behind A Date With History, a challenge sponsored by the climate campaign Tcktcktck, the Natural Resources Defense Council, and Climate Nexus. They invited anyone between the ages of 13 and 30 to write a speech addressing the attendees of the Earth Summit in Rio next month.

Tell the bigwigs about what kind of future you want, they said. The best speechifier will win a trip to Rio -- and possibly a chance to address the gathering in person.

The videos streamed in from the far corners of the planet. The web-surfing public narrowed the field to 22. And a star-studded jury including Leonardo DiCaprio and Daryl Hannah picked the winner.

Her name is Brittany Trilford. She’s 17, from Wellington, New Zealand, and yeah, she’s got some things to say to the folks who are in charge -- about broken promises, about the consequences of corporate and government actions, and about what we could learn from nature about how to run the planet.

Click to embiggen. (Photos c/o the Center for PostNatural History.)

Want to learn about dinosaurs and elephants and mountain gorillas? Head to your local natural history museum. But if you’re looking to study up on genetically engineered corn, lab rats, or Sea-Monkeys, get thee to the north end of Pittsburgh. There, on a rough little commercial strip with a bike shop, a tattoo parlor, and art galleries, you’ll find the Center for PostNatural History, an outfit run by a local art professor for the express purpose of exploring all the stuff the natural history museums leave out.

Rich Pell, the scruffy proprietor who teaches electronic media classes in the art school at nearby Carnegie Mellon University, sat behind the counter on a recent afternoon wearing a T-shirt from the Smithsonian decorated with a diagram of the tree of life. He explained that his mini-museum focuses on “intentional human changes to the biological world.” Read: dog and chicken breeding, genetically modified fruit flies, and everything in between.

"In a post-natural family tree, the common ancestor always leads back to a person," he explains -- "a breeder, a hobbyist," or a white-coated lab tech.

Well, it’s not the Horsemen of the Apocalypse, but it’s a start.

A coalition of U.S. environmental and social justice groups has asked President Obama to step up and attend the Earth Summit, a gathering of international bigwigs next month in Rio. It'll be an important opportunity to meet influential people from other countries, attend critical meetings, and lead high-level negotiations. Oh, and figure out how to build a green economy, Van Jones-style, around the globe.

Steve Coll is a master at getting behind locked doors. As an investigative journalist with two Pulitzer Prizes to his name, Coll has cracked the likes of the Central Intelligence Agency and the bin Laden family. But he had never met an institution quite as closely guarded as his latest subject, ExxonMobil, a company whose $550 billion in revenue last year dwarfs the Gross Domestic Product of most nations.

“They’re very disciplined, they’re very tightly organized, and they have a very emphatic policy of avoiding press coverage,” says Coll, a longtime editor at the Washington Post who is now a staff writer at the New Yorker and director of the New America Foundation, a Washington, D.C., think tank.

It took three years to get into the heart of this beast, but Coll ultimately did it, even landing interviews with the company’s longtime CEO, Lee Raymond, a chemical engineer by training who famously denied that humans were causing climate change, and poured company money into climate denial organizations and campaigns.

As you may have heard, President Obama is being cagey about whether he'll attend the Earth Summit in Rio next month. You know, it's just the FUTURE OF THE PLANET that’s up for discussion. Nothing big. Maybe he’ll go. Maybe not.

As it happens, we were in the same situation 20 years ago, as the 1992 Earth Summit approached and George Bush Sr. was giving it the old, "Well, maaaaaybe ..."

Back then, a group of the major, mainstream environmental groups in the U.S. rallied for the cause. To convince Bush he should attend, they enlisted none other than Darth Vader. Well, his voice, at least -- the actor James Earl Jones. They made the spooky film clip below, replete with -- is that the Pony Express or the Horsemen of the Apocalypse? -- and then ran it in movie theaters around the country. Jones did the voiceover. Need I even tell you that Bush Sr. decided to attend?

In my research into the 2012 Earth Summit, I’ve noticed very little action from the major U.S. greens. A handful of them, including EarthJustice, the Natural Resources Defense Council (NRDC), the Nature Conservancy, and the Pew Environment Group, have been involved, along with groups focused on clean energy, sustainable agriculture, and other issues, but where’s the old guard that sponsored the Darth Vader ad two decades ago? I decided to do a little poking around.

Photo by Richard Masoner/ Cyclelicious.

Today, America kicks off National Bike Month, our annual homage to two-wheeled travel. Here in Seattle, Grist’s hometown, every month can seem like bike month: Hearty souls ride in weather when full scuba gear is requisite. But today brought sunshine, and cyclists swarmed the streets, swerving through traffic, towing kiddie trailers through downtown rush hour, and generally acting like they owned the place.

It was great to see so many people out riding. I was also afraid I was going to see someone die. So for the sake of a safe and successful Bike Month, Grist is offering up a challenge to would-be bike commuters everywhere -- and a few suggestions on how to get started.

Get your ass on that bike!

Photo by Gandroid.

News flash: World leaders will gather in two short months at the 2012 Earth Summit in Rio de Janeiro to discuss the future of the planet. You may have caught the news stories last week about President Obama’s failure to RSVP. You’re forgiven if you missed them. You’re not the only one who just said, “Earth Summit, what?”

But this is for real. And there are a few things that you, good Jedi knights, ought to know about it.

1. It’s kind of a big deal.

Photo by porchlife.

When the leaders of more than 100 countries meet this June to discuss the small matter of the Future of Life on Earth, President Obama might be there. Then again, maybe he’s got a golf match scheduled that day. He’s not saying.

Yes, it’s true, the guy who just picked up an early endorsement from Big Green groups like the Sierra Club and the League of Conservation Voters, the man who announced in his last State of the Union Address that “America remains the one indispensable nation in world affairs,” may be a no-show at the 2012 Earth Summit in Rio de Janeiro, Brazil.

When asked about the president’s plans on Tuesday, U.S. Special Envoy on Climate Change Todd Stern told The Washington Post, “I don’t have any understanding that the president has any intention of going.” A White House spokesperson was noncommittal: “I don’t have any scheduling announcements at this time.”

Ouch. What ever happened to “Love Your Mother”?

Photo by Greg Hanscom.

Denis Hayes is about the last person on the planet you’d expect to find walking around a construction site in a hardhat, chatting up engineers and contractors. Hayes is best known as the guy who coordinated the first Earth Day, back in 1970, when he was 25. Since that time, he has earned a reputation as a fierce defender of the environment, raking in every imaginable green accolade. Today, he is honorary chair of the Earth Day Network by night and by day,  president and CEO of the Bullitt Foundation, a major force in conservation in the Northwest.

But Hayes is full of surprises. He directed the National Renewable Energy Laboratory under the Carter administration and has taught engineering at Stanford. He can talk BTUs-per-square-foot-per-year with the best of them. Which is handy, because at the moment, Hayes is orchestrating the construction of a new, uber green headquarters building for Bullitt. The building sets out to meet the Living Building Challenge, which means, among other things, that it will generate all of its own water and electricity. The latter is no small feat, when you consider that the building is in infamously gray Seattle – not exactly a Mecca for solar power.

With Earth Day 2012 looming (it's Sunday, people!), I caught up with Hayes to talk about the big day, green building, and his prognosis for the planet.