When businesses dip a toe in the rising sea of corporate action on climate change, the first box they check before diving in involves tabulating their own greenhouse-gas inventory. In getting your corporate house in order, the first step is defining where your yard ends and your neighbor's begins. The good news: There is a clearly accepted international standard providing guidance to companies sorting "what's in" and "what's out" for their GHG inventory. The Greenhouse Gas Protocol: A Corporate Accounting and Reporting Standard is the playbook everyone is working from. The bad news: Some issues are more clearly defined in …