Dire climate-change warnings have become a mainstay of politics. This is particularly true for state and local politicians whose coastal constituents stand to be most affected by rising sea levels. Mayors declare that impending eco-dangers represent an “existential threat,” and that significant portions of their cities will be submerged without swift and dramatic action. But do municipalities disclose these perilous environmental risks to potential bond investors?

The Government Accountability Institute undertook a yearlong study of 40 major cities to find out if mayors’ apocalyptic projections about climate risks are factored into the interest rates on the municipal bonds their cities issue. The results revealed a gulf between the words municipal leaders speak and the disclosures cities make. There was no statistically significant difference in the interest rates for bonds issued by cities in high-risk locations for climate-change devastation versus those issued by low-risk cities.

The study compiled 100 bond issuances for 20 cities at risk of climate-induced sea-level rises such as New York and New Orleans, as well as 100 issuances for 20 low-risk, inland cities such as Chicago and Kansas City. Greater risk to investors should produce a higher bond interest rate, or “coupon rate.” But the average rate for at-risk cities was 4.21% versus 3.99% for low-risk cities, and our analysis found that this difference of 22 basis points was not statistically significant. The study controlled for factors like type of bond, maturity and purpose, which also affect interest-rate variation.

The study also found scant mention of climate change in bond disclosure documents. The disclosure statements of the 20 at-risk cities totaled 4,361 pages. Phrases like “climate change” and “sea-level rise” appeared fewer than 100 times across all 20 at-risk cities in the context of the issues addressed in this study. Further, 12 out of the 20 disclosures for at-risk cities did not mention climate language in the same context.

The contrast between what mayors say in public and what cities disclose in bond language is often stark. New York’s Bill de Blasio has called climate change an “existential threat” and a “dagger aimed straight at the heart” of the city. Yet New York and the Port Authority of New York and New Jersey barely mentioned climate change or rising sea levels in their risk statements to investors.