Our Going Green columnist, Dennis Allen, has been building for more than 40 years, starting soon after the 1973 oil embargo got him interested in residential solar systems. His first forays in solar homes in Santa Barbara expanded into “whole-house” approaches like high-volume fly-ash concrete (which emits half the greenhouse gases of standard concrete), dual-flush toilets, and thin-film photovoltaics on a curved standing-seam roof. With the planet in crisis, new approaches to tackling climate challenges occur every day, he’s found, giving him more article ideas all the time. “Whether related to building or other aspects of the problem,” said Dennis, “I love learning about the new ideas and the latest science.”