by Greg Silverberg figures by Kaitlyn Choi Cleantech is a troubled sector Scientists know from geological data that carbon dioxide concentrations in the atmosphere have been below 300 parts per million for nearly 1 million years.  However, for about a century, carbon dioxide concentrations have been rising at a rate unprecedented in these data and are now approaching 400 parts per million.  Carbon dioxide acts … Continue reading Innovating in a New Market: Challenges for Cleantech