America’s CEOs will soon be receiving questionnaires in the mail from something called the Carbon Disclosure Project. While the CDP survey of the companies’ greenhouse gas emissions may seem innocuous, responses to those questions may put businesses at risk of financial liabilities that dwarf the tobacco industry’s $250 billion settlement with state attorneys general.

The CDP has polled the world’s 500 largest companies, asking various questions about their actions and attitudes toward global warming. The CDP ominously refers to the clout of the 143 institutional investors who have signed the survey letter: “As institutional investors representing $20 trillion in funds under management, we are continually examining our portfolios in order to assess the potential risks and opportunities relating to climate change for companies in which we invest.”

That thinly-veiled threat works: 245 companies completed the first CDP questionnaire in 2003, and 300 companies completed the second questionnaire in 2004.

But here’s why America’s CEOs should toss the CDP letter in the circular file.

First, despite the success that environmental activists, their allies, and the media have had in convincing themselves that humans are altering global climate for the worse and that implementing greenhouse gas emissions caps is now the only hope of saving the planet from catastrophic climate change, global warming actually remains a hotly-disputed scientific issue among scientists.

Experts don’t agree on whether humans are altering global climate, whether any such alteration would necessarily be harmful, whether anything at all could be done to avoid any potentially harmful climate change, and whether any such action would be economically feasible and cost-effective.

Next, many of the CDP’s institutional investors who claim to be concerned about the potential business risks of global warming actually have financial incentives for fomenting global-warming hysteria

Among the CDP letter’s signatories are self-proclaimed “socially responsible” investment managers such as the Calvert Group, Domini Social Advisers, and Walden Asset Management. Global warming is a significant part of their marketing strategy for attracting new investors. Insurer Munich Re, another CDP signatory, promotes global warming in the hopes of eventually being able to blame it for natural disasters so the company can seek indemnification from U.S. businesses and taxpayers. Munich Re, apparently, is more than happy to accept premiums for writing risky policies, but not too happy when Mother Nature forces it to make good on claims.

Politicized state pension funds, such as CDP letter signatories Connecticut Retirement Plans and Trust Funds and New York State Common Retirement Fund, have petitioned the Securities and Exchange Commission to require financial disclosure of global-warming liabilities – setting the stage for class action litigation – even though no one knows whether any damage giving rise to any liability will ever occur. Among the letter’s signatories are many European and Japanese institutional investors whose nations stand to benefit economically from global-warming hysteria. The global warming treaty known as the Kyoto Protocol would, if ever implemented domestically, provide Europe and Japan with competitive advantages over America, the world’s largest greenhouse gas emitter and, therefore, the nation that would be most drastically affected by the treaty’s provisions. And if CEOs still don’t understand the global political and economic ramifications of global warming hysteria, they ought to understand lawsuits and liability.

Disclosing greenhouse gas emission levels to environmentalists and their political allies – who happen to be well-connected to trial lawyers – can only serve as a basis for proving and apportioning global warming liability. A few global warming lawsuits have already been filed. More are on the way. Why assist dubious plaintiffs with pre-trial discovery?

Mr. Milloy publishes CSRwatch.com and is an adjunct scholar at the Competitive Enterprise Institute.