GLOBAL INSURANCE COMPANIES DIDN'T JUMP ON the sustainability bandwagon just yesterday. For example, Lloyd’s published a report titled “Climate Change: Adapt or Bust” back in 2006. But for insurers, making sustainability part of their business and finding common ground in a fragmented market are easier said than done. Many environmental, social responsibility and corporate governance (ESG) issues are “too big and complex and need widespread action across society, innovation and long-term solutions,” says Astrid Zwick, head of corporate responsibility at Munich Re, which manages €248 billion ($320 billion) in assets.

So in June the United Nations Environment Program Finance Initiative (UNEP FI) and 30 insurers representing a total $5 trillion in assets launched the Principles for Sustainable Insurance (PSI)....