Wednesday, August 10, 2016 – 12:59amThis article orignially appeared in the Verdical Group blog. Every year, about 15 billion tons of carbon dioxide are emitted into the atmosphere from concrete production alone. As cities continue to grow (according to the U.N., world urban populations are expected to increase by 84 percent by 2050), the amount of polluting building materials being created will increase right along with them. And it isn’t simply the materials that are causing problems.…