Some of the world's biggest companies are at serious risk of cost blowouts, regulatory burdens and reputational damage, according to a new report from the London-based Ethical Investment Research Services.

The report, The state we're in: global corporate response to climate change and the implications for investors, focused on the 300 largest cap global companies listed on the FTSE All World Index. It found that over a third (35.6%) of companies in the global 300 are assessed as high or very high impact for climate change, representing over a $6.8 trillion market cap.

The study also found that these companies weren't putting their money where their mouths were. It found that 84% of high risk companies have a corporate-wide commitment to climate change. But only 14% link board remuneration to climate change strategies. And only 25% publish a long-term strategic target to reduce emissions. Targets are an important indicator of a companies true commitment to reducing their impacts.

It also found that 81% disclose either absolute or normalised data but only 9% disclose the scope of their emissions against the Greenhouse Gas Protocol.

All up, this represents a real risk to investors. Lack of consistent and comparable emissions data is likely to become a significant issue.