Schumacher College, one of the world's preeminent and pioneering colleges of sustainability, offers a variety of short courses (days to a month) as well as an education certificate and a one-year MSc in Holistic Science. Their catalog says, "Participants come to Schumacher to identify tools and skills that will work for them at the cutting edge of their practice. The College is open to any individual with an enquiring mind, from any background. Previous participants have included business consultants, educators, artists, and designers." Check out their web site, Email them, or Call +44 (0)1803 865-934.
Peter Head, a Director of Arup, one of the world's leading urban engineering and plannning firms, said of his experience, "It helped me become more deeply rooted in my commitment to developing sustainable cities. I recommend professionals spend time at Schumacher College as i know it is a place where future leaders are developed."