There are some threats you have to love. The threat of litigation facing numerous corporations places a strong check on the oft-rampant carelessness regarding waste disposal, emissions, toxic material use, and so on.  Those companies that have lead the way in cutting edge reductions of negative environmental impact and research into regenerative processes have also smartly avoided hefty fines and taxing litigative measures less environmentally conscious firms have fallen prey to. 

The inherent risk managment enforced by sustainable practices can be illustrated in a variety of forms - for example, even experts in Finance agree there is significant risk aversion in a strategy of investment in socialy responsible investment funds. The companies that make up these portfolios are often so proactive regarding environmental impacts and so cognizant of the value in stakeholder-based focus rather than shareholder based focus that they generate substantial returns for investors.  Clearly the default risk posed by bankruptcy is mitigated by these green strategies and thus payback is actually more assured by some of these funds. 

thanks for the info, zm!