In “A Zero-Emissions City in the Desert”, Kevin Bullis, Technology Review’s energy editor, writes of a nearly empty, dusty building site in the Persian Gulf: “[It] is the start of a vast experiment, an attempt to create the world’s first car-free, zero-carbon-dioxide-emissions, zero-waste city. Due to be completed in 2016, the city is the centerpiece of the Masdar Initiative, a $15 billion investment by the government of Abu Dhabi … . The new development, being built on the outskirts of Abu Dhabi city, will run almost entirely on energy from the sun and will use just 20 percent as much power as a conventional city of similar size.”

Nothing like Masdar City has ever been attempted. Although zero-emissions residences and commercial buildings already exist, larger clean buildings have never worked very well. ­Oberlin College’s Lewis Center already has some of the features that Masdar City’s designers wish to deploy on a grander scale; but the center consumed far more energy than its architects had anticipated, and only the addition of a solar array in a nearby parking lot allowed the college to claim, dubiously, that the building itself produced as much power as it used. Certainly, no one has ever raised a small city to these standards.

Insofar as many environmental engineers doubt that something as complex as a city could ever be entirely green, Masdar City is a triumph of optimism. But if the optimists are right, such a massive demonstration may be necessary. As the chief executive of a sustainable-design company puts it, “People say, ‘Gee, that would be great … but obviously it’s not possible.’ Once you can point at something, it takes away a lot of those arguments.”

Elsewhere in this issue of Technology Review, we unveil the 10 emerging technologies that we think have greatest potential to change our world. Among them is a nanofluidic chip that could lower the cost of sequencing DNA so that the entire human genome could be read in eight hours for less than $100. ­Lauren Gravitz explains, “Despite many experts’ doubt that whole-genome sequencing could be done for $1,000, let alone a 10th that much, BioNanomatrix [the startup that invented the chip] believes it can reach the $100 target in five years” (see “$100 Genome”). That would be a tremendous thing. A cheap, rapid sequencing tool could make personalized medicine a practical reality: a doctor could biopsy a malignant tumor in a patient’s lung, sequence its DNA, and then use the genetic information to design the treatment best suited for that particular variant of the cancer–“all for less than the cost of a chest x-ray.”