Florida is suing the climate-risk modeling firm First Street Technology Inc., accusing it of penalizing state homeowners with risk scores based on flawed science.

Filed Oct. 23, the lawsuit highlights growing pushback against the scores, which are intended to give consumers more insight into homes’ exposure to fire, flood and other climate-related dangers. Nebraska brought its own, similar suit against the company in August.

Florida Attorney General James Uthmeier, a Republican who is running for reelection, said when announcing the action on X that First Street data is inaccurate and “homeowners deserve facts, not alarmist scores that hit their property values and their wallets.”First Street, which was recently acquired by MSCI Inc., uses computer models to estimate the threat to property of flooding, wildfire, extreme heat, wind and other hazards — now and decades into the future — down to the level of an individual address. MSCI didn’t respond to a request for comment.

Other companies model those risks, but First Street turns the estimates into 1-to-10 scores and makes them widely available through real-estate websites. The idea is to make transparent the climate-related risks to property and support informed purchasing decisions.

After First Street produced its first major report in 2020, real-estate sites including Zillow, Redfin and Realtor.com started integrating its risk scores. Connecticut’s state insurance department even partnered with the company to offer residents free assessments of their properties.

But the proliferation of climate-risk ratings has led to questions about the models behind them, how best to interpret them and what happens when a home’s score is wrong.

Last year, Zillow stopped displaying scores from First Street directly on listings after objections from the California Regional Multiple Listing Service. Home sellers and real estate agents have complained the scores may lower property values and hurt sales.

Climate-risk modeling is sophisticated, but its reliability decreases the smaller the geographic scale is. Bloomberg News in 2024 compared First Street’s granular 2020 flood-risk estimates for Los Angeles with an academic team’s and found that the two sets of results were widely divergent, overlapping just a quarter of the time.

In its complaint, Florida casts First Street’s work as advocacy rather than objective risk analysis, accusing the company of “climate chicanery” and “marketing fear to advance a climate activism agenda” while profiting from the information it sells about “fake” risks.

Madison Condon, a law professor at Boston University who researches climate risk, regulation and finance, said she has concerns about how First Street has marketed its information. But “there are also real concerns that a lawsuit of this type could chill the provision of physical climate-risk data in general,” she said. The modeling is inherently uncertain, “and scientific models can disagree without being willfully deceptive,” she noted.

Nebraska and Florida are taking on First Street as US homeowners face an affordability crisis, driven in part by sharply rising insurance rates. Florida argues that faulty risk scores could potentially affect residents’ insurance costs and coverage status since First Street data is also used by insurers.