Sustainability typically doesn’t show up as a neat row of dollar numbers to be added to a cost-benefit spreadsheet. As a result, decision-makers routinely ignore it. That may be about to change if the NPV+ method already applied by Martin O’Malley, a potential Democratic presidential candidate who used to be governor of Maryland, become widespread. Net Present Value Plus (NPV+) is an accounting methodology that factors in long-term environmental and social costs and benefits. It has been developed by Global Footprint Network‘s consultant Chris Nedler. What are governments waiting for?