This is a map of light pollution in the area around Austin, Texas.

Those purple markers (which are clickable at the map's website) indicate how much or how little night sky is visible. For the ones near the city core, the emphasis is on "little." In 2007, the city passed regulations aimed at reducing the amount of light that brightens the night sky, but old fixtures -- and the city's highways -- were grandfathered in until 2015.

Photo by rutlo on Flickr.

Yesterday, they took more direct action. The city council approved spending up to $15 million to replace or upgrade half of Austin's streetlights. The decision will result in the removal of existing plastic domes from under the lamps, which tend to diffuse the light broadly (and inefficiently). More importantly, it will also buy 35,000 LED lights, which use half the power of the existing bulbs and which last up to 15 years.

Mitt Romney pushed for smart-growth policies in Massachusetts. (Photo by Gage Skidmore.)

Everyone knows that "Obamacare" was modeled on Mitt Romney's Massachusetts health-care law. But did you know that a key Obama "smart growth" initiative -- the Partnership for Sustainable Communities -- was also created in the mold of a Romney program?

Tea Partiers rallied to quash funding for this Obama partnership last fall. Rep. Paul Ryan (R-Wis.), conservative darling, criticized the idea for the partnership when it first arose and accused the Obama administration of trying to impose "an urban-utopian fantasy through an unprecedented intrusion of the Federal Government into the shaping of local communities." The Republican National Committee recently warned that smart growth is part of a U.N. conspiracy (green helicopters, anyone?).

This is yet another issue on which the party's presumptive presidential nominee looks to be seriously out of sync with the GOP base.

Tara Hui points out an "illegal" Asian pear she's grafted onto an ornamental pear tree.

Ornamental fruit trees are the worst idea ever. And I'd argue they say a lot about our culture. As we’ve built and expanded cities, and planted public trees, we've decided that local fruit -- fruit you could pick right on the street -- was too messy. We wanted our fruit imported, wrapped in plastic, and safely compartmentalized in the produce aisle. So we bred trees accordingly. Pear trees with no pears. Cherry trees with no cherries.

Now this San Francisco-based group called the Guerrilla Grafters is challenging the very notion of the ornamental fruit tree. And they're working outside the law (city officials don't like rotten fruit on the sidewalk, nor the liability it suggests). They’re covertly grafting -- a practice of connecting two branches in a way that will allow their vascular tissues to join together -- fruit tree limbs onto the trunks of ornamental cherry, plum, and pear trees. (We’ve highlighted them before on Grist, but since NPR covered their illegal work again this weekend, I thought it was worth another mention.)

Loren Amelang is a pioneer in C++ programming, and his homebrewed live/work space is a monument to sustainable geekery, says Fair Companies.

The entire south side of his home is covered in solar capture devices: 1600 watts of photovoltaic power, solar hot water panels, a sunroom/greenhouse and a solar hot air collector.

This isn't just your usual passive house or living building, either: Amelang can control the entire thing from a smartphone.

No, this is not the world’s biggest Jenga game. (Image by Michael Green Architects.)

When most folks think “wooden building,” they conjure up images of rustic log cabins or ye olde fashioned outhouses. Architect Michael Green wants to whittle something decidedly more modern out of wood: skyscrapers.

The golden days -- when the traffic hadn't caught up with the lanes. (Photo by coltera.)

We can say this for our Great Urban Freeway Experiment: It seemed like a good idea at the time.

The time was the 1950s and '60s, specifically, and U.S. cities were watching their residents flee to the suburbs in alarming numbers. Their solution: Build giant freeways connecting city centers to the ’burbs, thereby allowing citizens to live the good life on the outskirts and commute to work in the urban core. It was an attempt to hang on to urban industrial might even as the city’s population bled (or drove) out.

When all was said and done, these freeways did salvage some downtown commerce, but they only accelerated the flight from the inner city. At the same time, they carved up historic urban neighborhoods, turned whole sections of cities into slums, and cut off many downtowns from their waterfronts. Legendary urban activist Jane Jacobs was among the first to fight the scourge of the urban highway, and by the late 1970s and early 1980s, it had become all but impossible to gain approval for new highways through urban areas.

It’s one thing to stop building urban freeways, however, and another thing entirely to tear down existing ones. For many city centers, those highways still look a lot like lifelines.

Image by Zhi Zheng, Hongchuan Zhao and Dongbai Song.

This theoretical skyscraper, the winner of eVolo's annual skyscraper design competition, would collect, purify, and store water in the Himalayas, helping to conserve and regulate it. It looks like a half pack of cigarettes in fancy holders, but it's not even the weirdest-looking skyscraper, not by a long shot. Below are some of the strange shapes that might crop up in the skyline of our more sustainable future.

Ellen Dunham-Jones. (Photo by Georgia Institute of Technology.)

Cross-posted from Next American City.

Ellen Dunham-Jones is a professor of architecture at the Georgia Institute of Technology and coauthor of Retrofitting Suburbia: Urban Design Solutions for Redesigning Suburbs, the quintessential guidebook for making sprawl more sustainable. She will be one of the featured speakers at the 20th Congress for the New Urbanism in West Palm Beach, Fla., this May. Here, she discusses vital demographic shifts, different redevelopment strategies, and some of the more impressive retrofitting projects going on in the U.S.

Q. A recent survey found that for the first time, most Americans prefer a walkable neighborhood to a large house. What do you think accounts for this shift, and what does it mean for how we plan our suburbs in the near future?

Photo by Trey Campbell.

Everything single part of a building, from the windows the the air conditioning and heating system, has become significantly more energy efficient over the past 20 years. And yet buildings, as a whole, are using more or less the same amount of energy they always have. What gives?

Rocky Anderson shows off the solar panels on his roof. (Photo by Kate Sheppard.)

When we last spoke with Rocky Anderson, he was kicking some serious butt for the planet from his position as the supergreen mayor of Salt Lake City, Utah. Anderson, an unflinching champion of issues ranging from climate action to gay marriage, quit politics in 2008 after two terms in office. But now he’s back, and this time he’s trained his sights on the White House.

Running for president under the banner of the Justice Party (his Facebook followers reportedly came up with name), and backed by a tiny, mostly volunteer staff, Anderson promises a grassroots, social-media-powered campaign that will give Obama and his yet-to-be-determined Republican rival a run for their money.

It will be no small task: Obama has raised a war chest of close to $100 million, according to The New York Times. Mitt Romney is sitting on $32 million. Anderson, whose platform centers on ridding American politics of the “corrupting influence of money,” is remarkably uncorrupted by that measure. Accepting a maximum of $100 per donor, he has raised less than $1 million so far. Like, way, way less.

But Rocky is fierce and determined, and he’s pissed about what short shrift American workers and the environment keep getting while the political elite and Wall Street fat cats get ever fatter. Given the outrage we’ve seen in the Occupy movement in recent months, his message is bound to strike a chord.

We caught up with the former mayor this week to see what in the world has gotten into him.