This year, Earth Day was bigger than ever, which prompted some hand-wringing over whether too many people were jumping on the green bandwagon. Wait a minute: Earth Day, too big? Didn't we want everyone on this bandwagon? Sustainability is a challenge we all face; our response to it could well define the 21st century. If we are going to succeed, it will take more than a "business as usual" approach. In fact, we believe the whole definition of "business as usual" needs to be upended. Business can no longer afford to ignore environmental warnings; environmentalists can no longer demonize business. Sustainability has made us understand, in a way we never would have before, that we all share a common fate. We need to face the reality that -- like it or not -- we're in this together. That's why we -- Sierra Club and The Clorox Company -- decided it was time to bridge the gap and come together as partners. For some, the idea was unthinkable. Had Sierra Club sold out? Was Clorox trying to greenwash? What could "the bleach maker" and the "oldest and largest environmental organization" have in common? The partnership we forged for the launch of the Green Works brand showed just how much.