This has been an eventful summer for all of us who care about the world. In June, we marked the 20th anniversary of the 1992 United Nations Earth Summit in Rio de Janeiro. In July, we recorded the hottest-ever month in the United States. In August and September, we listened to the two presidential candidates as they squared off on climate change in their respective convention speeches. And later in September, we learned that the drastic melting of the Arctic sea ice had set a new record, with ice covering just 24 percent of the surface of the Arctic Ocean.We don’t know whether President Obama or Mitt Romney will embrace a progressive environmental policy. We don’t know what the environmental leanings of the next Congress will be (which, at this writing, are hostile). But we do know what consecutive 100-degree days and steadily melting Arctic ice mean.Phenomena like these help explain why sustainability was definitely on the minds of the participants in Rio. Indeed, roughly 120 world leaders, along with tens of thousands of people from the private sector, NGOs, higher education and other civil society groups gathered in South America, once again, to facilitate decisions that could lead to a healthier, more equitable and prosperous world for all.As a member of the Core Discussion Leader Group for the UN PRME (Principles for Responsible Management Education) 3rd Global Forum, I participated in that gathering, as part of the kick off for the Rio+20 UN Conference on Sustainable Development.During my two weeks in Rio, we were all consumed with the challenges underlying the adoption of a new economic model, based on sustainable development and aimed at building prosperity for the medium and long term within a far more inclusive global economy.Yet, to my dismay, there was scant mention of the event in the world media. Granted, there were other pressing economic and political events dominating the landscape — from the Euro crisis, to the lingering tensions in Afghanistan, Pakistan and Iran, to the ongoing economic malaise in the U.S. Combined with the uncertainty surrounding the 2012 presidential election, it is not all that surprising that the summit drew limited attention in the U.S. or minimal commitment from government leaders across the globe.Looking back at Rio, many observers expressed complete dismay at the outcome.Kumi Naidoo, International Executive Director for Greenpeace International, referred to the summit as “a failure of epic proportions.” Author George Monbiot went as far to suggest that governments have “given up on the planet.” Even UN Secretary General Ban Ki-Moon lamented that the Rio + 20 Summit has “not lived up to the measurement of the challenge.” Indeed, the official outcomes document, The Future We Want, clearly fell short of expectations, given the environmental and social challenges confronting us. And many NGO leaders have argued that no agreement would have been better than the weak set of commitments that came out of Rio.I share in this frustration.And yet, I still came away from Rio with hope for our future. It is significant that business schools opened the summit. At the first Rio meeting, business leaders were at the margins and business schools were nowhere to be seen. Today, however, business leaders increasingly play a central role in shaping the future alongside political and civil society leaders. Everyone is stepping up their commitment to sustainable practices. While I realize that there is a certain PR element underlying many of these initiatives, and many of the commitments are incremental, it is also clear that many companies are making great strides in undertaking initiatives with a potential for real change.Business schools have also moved from the periphery to center stage, focusing on shaping managerial mindsets that are grounded in sustainable development. As the UN Inspirational Guide for the Implementation of PRME illustrates, many b-schools are changing curricula, refocusing pedagogy and research, and reorienting campus operations through increasingly visible sustainability initiatives.So, change is occurring; but we still need to do more — much more.Innovative ideas and initiatives — embedded in a collaborative spirit across governments, the private sector and civil society — are needed more than ever, given the environmental and social challenges we face. And our business schools must continue the changes that are beginning to take hold, ensuring that the next generation of professionals fully understands the critical importance of sustainable practice and the challenge of generating value in an inclusive and sustainable global economy.The time is now for all of us to work for the future we want.Tony Buono is professor of management and sociology at Bentley University.