As the world's biggest, union-bustingest retailer, gigantic sack of Chinese lead paint chips Walmart has the opportunity to push more money at sustainability than pretty much anybody else on the planet. Which is why the company, like IKEA before it, is committing to getting 100 percent of its power from renewable sources! But only in Canada. It's like they're trying to rub it in, those Canadians. Their debt load is manageable, their health care is still free, and hey, even their most bloated big-box retailer is a paragon of sustainable progressivism! Next thing you know they'll be taunting us from the …

At Sandia National Laboratories, a giant array of mirrors heats rings of metal oxides to 2,550 degrees F, allowing a beer-keg-size reactor to produce carbon monoxide or hydrogen gas out of CO2 or water. The result is known as syngas, and it can be further processed into the kind of hydrocarbon-based fuels (think gasoline and diesel) upon which our transportation infrastructure depends. The process represents some serious blue-sky thinking. In its current incarnation, it would take almost 500 square miles of mirrors to produce enough syngas to create 1 million barrels of oil a day. (The U.S. currently uses around …

How big is natural gas in Pennsylvania? This big, according to the Associated Press: More than half of the interstate natural-gas pipeline projects proposed to federal energy regulators since the beginning of 2010 involve Pennsylvania — at a cost estimated at more than $2 billion. That's hundreds of miles of pipelines that can move more than 4 billion cubic feet of natural gas each day. The new pipeline projects also bring the risk of explosions, which have been a particular problem for natural gas systems lately. Congress is supposed to take a new look at pipeline safety rules, last updated …

If you live in Florida and don't have a car, you may want to invest in a heavy steel overcoat. Florida is home to four of the top four most dangerous metropolitan areas for pedestrians -- Orlando, Tampa, Jacksonville, and Miami. In the wake of the Raquel Nelson case, the New York Times has turned its reporting eye on pedestrian fatalities, and the scene on Florida streets is pretty depressing: Sidewalks are viewed as perks, not necessities. Crosswalks are disliked and dishonored. And many drivers maniacally speed up when they see someone crossing the street. The danger rankings are based …

Canned tuna, a "magical wonder fish," is sooooo cheap. Just ignore that "shadowy multinational corporation" behind the curtain, and the bloodlust of Chicken of the Sea's creepy mermaid mascot: The "dirty little secret" that Greenpeace unveils in the video is the problem of innocent bystanders … uh, byswimmers. Basically, tuna fleets use fish aggregating devices to attract tons of tuna. But the devices also attract other fish, which get caught and sacrificed to the bottom line.

"Lilium Urbanus" envisions the city as a botanical, flowering from seed to sprout to village to metropolis. Its creators, Anca Risca and Joji Tsuruga, told Scientific American that their daily observation of urban growth in their home city of New York inspired the comparison: We embraced the idea of urban growth and saw it as something uncontrollable, having a mind of its own. Like a growing flower, a small town constructs larger buildings and becomes a flourishing city with skyscrapers for leaves, airport runways for petals, and airplanes for seeds. Our goal was to show that a city is like a …

A second leak at the Shell oil platform in the North Sea is proving harder to stop than the first. A Chinese protest against a chemical factory was one of the largest in three years -- at least 12,000 people -- and may herald a shift towards more public action in the country. Philadelphia Mayor Michael Nutter is exchanging ideas with leaders in Rio about greening their cities. How our tricksy brains are keeping us from drinking cleaned wastewater: "It is quite difficult to get the cognitive sewage out of the water, even after the real sewage is gone," says …

New York is becoming quite the haven of wildlife! There's the pigeons, the giant monkey on the Empire State Building, and now dolphins have been spotted in New York Harbor. The frisky sea critters haven't gotten into an empire state of mind in two years, so this is a big deal -- it means the water quality is better and the fish populations are rebounding. Of course, regular Grist List readers know that you can't always trust a dolphin, what with their mad lust-fueled killing sprees and everything. But that probably means that the tolerant Big Apple is the best …

Most cities these days are chock-full of foreclosed properties. Some foreclosed properties are chock-full of fruit trees, vegetable gardens, and other sources of fresh produce. That adds up to a lot of tasty plant matter going to waste -- unless people take it upon themselves to harvest food from abandoned houses, either for their own use or to distribute to shelters. That's not legal, but as a New York Times piece makes clear, that doesn't mean it's not a good idea. Voluntary foraging, where homeowners who have more produce than they can use open their gardens to people who want …

Steve Katsaros, inventor of the Nokero solar-powered lightbulb, recently told CNN that he decided to sell his bulbs rather than give them away, even though it runs counter to the traditional model of aid to the developing world. "Many NGOs say it's making money on the back of the poor, but I love to make money on the back of the poor," says Paul Polak, author of Out of Poverty, the 2008 book that inspired Katsaros. He was probably at least half-joking, but he's got a real point: giving stuff away doesn't actually help local economies, whereas selling things cheaply …