One source of significant data on greenhouse gas emissions by issuers is the Carbon Disclosure Project, which conducts an annual survey of thousands of companies around the globe. The survey asks for detailed information about greenhouse gas emission inventories and reduction targets, including information on corporate governance and physical risks, as well as competitive impacts of climate change.

The Carbon Disclosure Project has been sending questionnaires to issuers since 2003. The number of issuers receiving, and responding to, questionnaires has expanded substantially over that time, from 235 responses to the first questionnaire to 3,050 responses from companies in 60 countries last year. There is no legal requirement for a company that receives a questionnaire to respond to it. Although participation is voluntary, as a practical matter, a high percentage of the companies that receive questionnaires provide a response because of the perception that investors will punish issuers that do not respond. This amounts to a 65 percent overall response rate, including an 82 percent response rate among the Global 500 companies.

There are several different types of questionnaires issued by the Carbon Disclosure Project, and each has a different response deadline. The main questionnaires and the associated deadlines are Investor (May 31), Water Disclosure (June 30), and Supply Chain and Public Procurement (July 31).

Preparing a response to a Carbon Disclosure Project questionnaire requires careful coordination among an issuer's environmental and securities experts. The environmental experts must provide accurate information on greenhouse gas emissions inventories and future expectations about emissions levels. The securities experts must compare the information to be provided in the response to existing disclosures in securities filings. The response to the Carbon Disclosure Project questionnaire should not contain material information unless the information already has been disclosed in securities filings.

The responses to the questionnaires have provided the Carbon Disclosure Project with a wealth of information about greenhouse gas emissions. In 2010, the Carbon Disclosure Project issued more than 40 reports summarizing the information provided in the responses. Some of the reports provide information on companies in a particular country or geographic region. Others provide information on particular categories of issuers such as the S&P 500, while still other reports provide information on particular industrial sectors, such as utilities.