The most advanced green buildings don’t just consume fewer resources. Some are made from materials that are taken quite literally out of thin air—forged from carbon dioxide and methane that would otherwise pollute the atmosphere. Everything from walls and furniture to the roofs above our heads can be made from greenhouse gases.
Removing atmospheric CO2 and putting it into something useful or storing it somewhere safely is called carbon sequestration. Carbon can be sequestered by scrubbing CO2 out of the exhaust stream in power plant smokestacks and pumping it deep underground, although this process still remains largely untested and prohibitively expensive. Another promising new technology transforms greenhouse gases into the fuel methanol.
There are even artificial “trees” developed by researchers at Columbia University which use sodium carbonate-impregnated “leaves” to capture carbon in a chemical reaction, producing sodium bicarbonate, also known as baking soda. The baking soda can later be heated to release pure, sequestration-ready CO2. But the problem with these ambitious new technologies is that few consumers have been willing to pay for them.
Trapping carbon in building materials, on the other hand, is a lot cheaper. The products that do this are generally cost-competitive with less sustainable options, and we don’t have to wait for big corporations or governments to act. We can choose to use these green alternatives in our own homes.
Granted, these materials are unlikely to make a big dent in our current climate crisis unless we combine their use with wasting a lot less energy. In 2014, the average U.S. residential utility customer consumed 10,932 kilowatt-hours of electricity, resulting in the emission of over seven tons of carbon into the atmosphere.
We already know some good ways to clean up our act. Insulating better and purchasing the latest energy-efficient appliances are two places to start lowering the carbon footprint of our homes. But to fully earn the Green Housekeeping Seal of Approval, you’ll also need to get smarter about what your house is made of. Fortunately, there is a growing number of cleaner and greener options to choose from.
Cement is the most widely used material in the world—and that is a problem. Making cement is a notoriously dirty business, consuming lots of energy in its heat-intensive manufacture and creating chemical reactions during production that account for 5 percent of our global CO2 emissions.
But not all cements are created equal. The sustainable cement maker Solidia Technologies has slashed its carbon output by tweaking the basic recipe, using less limestone and lower roasting temperatures. The cement further reacts with CO2 during the curing process (when it hardens), trapping the carbon permanently in the concrete matrix.
The company tells Smithsonian.com that their manufacturing process spews up to 70 percent less carbon into the atmosphere than conventionally produced cement. That amounts to over a thousand pounds less CO2 created for every ton of cement produced—not bad for one of the highest-emission industries on Earth.