ADP Co-chairs Daniel Reifsnyder (left) and Ahmed Djoghlaf (center) say their negotiation work is difficult but worth it. "We only have one planet, you know," Reifsnyder says. "We have to protect it." Courtesy of IISD/ENB hide caption

itoggle caption Courtesy of IISD/ENB

Negotiators at their round table in Geneva, where talks are being held about Iran's nuclear ambitions. Denis Balibouse /Reuters/Landov hide caption

itoggle caption Denis Balibouse /Reuters/Landov

Iranian President Hassan Rowhani earlier this month. Behrouz Mehri /AFP/Getty Images hide caption

itoggle caption Behrouz Mehri /AFP/Getty Images

Russian President Vladimir Putin and President Obama when they sat down together in June at a G8 summit in Northern Ireland. Alexi Nikolsky /EPA /LANDOV hide caption

itoggle caption Alexi Nikolsky /EPA /LANDOV