Jon Christensen, adjunct professor at UCLA’s Institute of the Environment and Sustainability, has a career-spanning history dealing with environmental issues as a journalist for countless notable magazines, journals and other publications. Now, Christensen is settling into a new role with UCLA that began in 2012. Christen calls Los Angeles a “great global, diverse city facing global environmental challenges and opportunities.” UCLA offers the setting to study these challenges and opportunities in an ever-changing urban environment. “[Humans] are leaving a signature in the geological record,” Christensen says. “Shifts in the geological record define geological eras. It’s very clear that we’re now in a different kind of era.” Visit the UCLA Institute of the Environment and Sustainability’s website. Jon Christensen originally appeared on Green is Good on June 10, 2013.