The CFO's responsibilities are ever-increasing -- with finance chiefs sometimes overseeing everything from IT to corporate counsel to HR. Now, add the sustainability effort to their workload at more and more corporations.In a new working paper, Harvard Business School's Robert Eccles and George Serafeim and London Business School's Ioannis Ioannou report that, according to their study of 180 companies, those firms that voluntarily adopted environmental and socially responsible policies many years ago ("high-sustainability companies") outperform ones with almost no sustainability-related policies. The outperformance is measured both in stock price and accounting performance. High-sustainability companies also are more likely to link top-executive pay to sustainability metrics.Sustainability is an increasingly important responsibility even finance chiefs whose paychecks are unaffected by sustainability policies. "Traditionally, sustainability issues have fallen outside the jurisdiction of the CFO. CFOs ran the numbers, letting others handle soft issues such as social responsibility and corporate citizenship," notes a special report on CFOs and sustainability this summer from Ernst & Young. "Sustainability issues and financial performance have begun to intertwine. CFOs are getting involved in the management, measurement, and reporting of the companies' sustainability activities. This involvement has expanded the CFO's role in ways that would have been hard to imagine even a few years ago."Certifying Controls and ProceduresGuidance from the Securities and Exchange Commission put some environmental issues squarely in the CFO's purview in 2010. Specifically, a company's CEO and CFO must certify that the company has "controls and procedures" in place to disclose material risks related to climate change. Finance chiefs, E&Y notes, often find it necessary to address their companies' environmental and social-responsibility programs in investor relations.Moreover, as companies feel more shareholder and marketplace pressure to deliver transparent data on their sustainability practices, they will increasingly look to their CFOs for help and guidance.CFOs, says E&Y, "understand both the rigors and the benefits of an external audit, and are familiar with the systems and controls used in nonfinancial reporting. This experience can greatly benefit corporate sustainability teams in selecting and working with a third-party assurance provider."Consider Performance GoalsIf sustainability issues are here to stay, it would behooves CFOs to embrace their sustainability-related responsibilities proactively. The E&Y report recommends a few steps finance chiefs can take now to lead the way in enhancing their companies' value through socially responsible activities, such as engaging in deeper dialogue with shareholders to improve the quality of sustainability-related disclosure. CFOs might also consider using performance goals and other nonfinancial metrics to link company goals and environmental strategy.But the most important recommendation from the report may be for finance leaders to ensure that there is collaboration among those responsible for executing sustainability activities."The finance organization, through its accounting systems, must provide the sustainability function with the information needed to do its job," the E&Y report notes, "...no matter how the company structures these responsibilities."