Northwest Public Radio’s enterprising Tom Banse was working on a collaborative project on wood smoke in this region when he came upon a much bigger story — a global one. The effects of wood stoves here are just a puff of, well, smoke compared to the ills suffered, and perpetrated, by up to 3 billion people around the world who depend on biomass — wood, charcoal, dung, and the like — to cook their food. Smoky, inefficient cookfires such as the classic “three rock” arrangement cause tens of millions of respiratory ailments and some 1.5 million deaths each year, more than malaria.

The soot they produce is a potent greenhouse agent in itself, and if it falls on snow — say, Himalayan glaciers or arctic icepack — it reduces the snow’s albedo, making it absorb more heat and melt faster, a proverbial feedback loop. And gathering or buying firewood consumes an enormous share of many power people’s time and income. It’s a main cause of deforestation, degrading habitat, triggering erosion, and further contributing to global warming — another feedback loop.

Banse found that a growing movement is attempting to remedy this situation by replacing those dirty cookfires with clean, efficient stoves that consume less fuel and produce much, much less smoke and illness. And that the Northwest is home to a “burgeoning cluster of lifesaving stove designers” — at least four of them, anyway.

The clean-stove movement has indeed come into its own recently, with an outpouring of media and official attention. Last year, the United Nations Foundation, together with the U.S., German, and Norwegian governments and others, launched the most ambitious initiative yet, the Global Alliance for Clean Cookstoves; Secretary of State Hillary Clinton, who got attuned to the issue when she traveled as First Lady and saw poor people staggering under heaps of firewood, was a main instigator. It proposes not merely to send clean stoves around the world, but to insinuate them so thoroughly into local economies and customs that people from Kampala to Kathmandu will keep manufacturing and buying them on their own.

But valuable and impressive as all this is, it’s not the full story, nor a perfect solution to the cookfire conundrum. A fire-free alternative, variously described as a “solar cooker” or “solar oven,” can not only reduce but eliminate toxic smoke, costly fuel, and their attendant ills. Solar cookers can be assembled from everyday, even scrap, materials for less than the target cost ($10) of clean-burning stoves.

Clean stoves stand to dirty cookfires as Priuses and Fiestas do to smoky old gas guzzlers. But solar cookers are like bicycles — except they don’t entail anything like the exertion and loss of capacity and functionality that come with switching from a car to a bike.

Solar cookers are an idea that’s been hiding in plain sight for a very long time — and Seattle is a hotbed for them too. In 2009 the Financial Times awarded its $75,000 FT Climate Challenge award for “the most innovative and scalable solution to the effects of climate change” to the Kyoto Box, a cheap cooker made out of an insulated cardboard box lined with tinfoil and black paint, with a clear acrylic cover to catch the heat (a beneficial application of the greenhouse effect). It was a ringing endorsement of the idea of solar cooking, and of the appeal of super-cheap, simple design; I felt the same way the first time I saw a similar box cooker in action, in Brazil a few months before the FT contest. But it also seems a gesture of astonishing naiveté by a sophisticated newspaper, a bit of clever brand appropriation, and an indication of the widespread ignorance of solar cooking.

According to various promoters and practitioners of such cookery, the idea goes back to the 18th or 19th century. Box cookers like the Kyoto have been around for decades. “We laughed at that [prize choice],” says AmyJo Mattheis, executive director of the California-based nonprofit Solar Cookers International. “His cooker doesn’t even work!” Indeed, a promotional video of the original cardboard model suggests it wouldn’t: It had heat-absorbent black where it should have had reflective foil. A new model, apparently developed with that $75,000 prize, is made of sturdier polystyrene, with reflective lining.

A range of designs have been devised to capture and concentrate the sun’s rays for cooking. (Wikipedia shows others.) Inclined lids and plywood make the simple box more efficient and sturdier. Open boxes, foiled or mirrored across their entire inner surfaces — some ingeniously shaped, fanning out like card hands — bounce the rays onto a blackened pot, bagged in heat-resistant plastic for greenhouse value. Parabolic designs, some homemade and some exquisitely engineered, concentrate the rays even more intently. The slickest, naturally, seem to be from Germany, or to be made using a German design in Kenya.

These can get hot enough to sear a crunchy crust onto a casserole or roast, if desired — or to burn it, if neglected. The glass-topped and plastic-bagged versions, by contrast, self-regulate to guard against burning: When water inside boils, it steams up the cover, blocking the rays and cooling the contents. The temperature stays just over 200 degrees Fahrenheit.

Last year I salvaged a parabolic antenna Direct TV had left behind, thinking to make a cooker out of it but wondering if it was too small. Now Joann Kerr, a graphic designer, cofounder of Sustainable Northeast Seattle, and coordinator of perhaps this town’s widest-reaching solar-cooking effort, tells me it’s been done. It works.

Kerr and the Sustainable Northeast group got the solar cooking bug about three years ago. They discovered that one of their neighbors, Tom Sponheim, had been doing it for some 20 years, and had even served as Solar Cookers International’s webmaster. “Tom will take his solar cooker out in March and use it into November if it’s still sunny,” Kerr says admiringly. I couldn’t reach Sponheim for this story, but he presents a fan-like, clamshell-shaped cooker, made from a cardboard box and tinfoil and designed by a Malaysian “origami master,” in this video. He says it takes about an hour to assemble, maybe two the first time, and will "bake bread in Seattle in Feburary."

For the past three summers Sustainable NE Seattle has hosted cooker-building workshops, using the origami clamshell design. At first, a $3 fee covered the materials; now $15 pays the instructor as well. Kerr estimates 150 to 200 people have attended, and some have gone on to teach their own classes. Perhaps solar cooking will spread the way belly dancing and marimba playing did in past decades.

Each July Sustainable NE Seattle hosts a solar cookout. “People bake bread, cook meat dishes, boil eggs and potatoes,” says Kerr. “It’s surprising how they’ll experiment.” One wrapped foil over various containers lying around the house: a laundry basket, a Rubbermaid plastic bin, etc. “A black pot suspended over them cooked just fine.”

This past July, the Sustainable Northeasterners determined to assemble the largest array of solar cookers ever, anywhere. But the day rose cloudy, and most chickened out. Those who came anyway had a fine afternoon cook-in. If you use a clothesline or otherwise depend on sunshine in Seattle, you learn to have faith in clear afternoons.