The Docket

First Street runs CMIP6 climate projections forward thirty years, layering sea level rise and rainfall pattern shifts onto property-level flood models. Each address gets a Flood Factor score based on cumulative future risk, not what happened last decade.

FEMA flood maps use historical flow data, period. No climate adjustments, no forward modeling. Some maps date to the 1970s because Congress won't fund adequate updates. They're regulatory snapshots for insurance pricing, frozen at whatever conditions existed when surveyors last showed up.

First Street counts 14.6 million at-risk properties nationwide. FEMA counts 8.7 million. In Kentucky's Appalachian counties alone, that's 22,086 properties versus 6,562. The gap means millions of homeowners are underestimating their exposure because the official maps say they're fine.

Insurance companies run their own catastrophe models using IPCC scenarios but rarely publish methodology details. Most do "exploratory" analysis of possible futures without stress testing worst cases. Premium calculations vary wildly depending on whether carriers use FEMA's outdated maps or fully risk-based assessments.

Platform divergence spikes in places FEMA mapped poorly. First Street found four times more at-risk properties in Utah, Wyoming, and Montana than FEMA did. Cleveland County, Arkansas: FEMA identified twelve properties at risk. First Street estimated 1,500.

First Street validates against historical flood reports and FEMA claims data. Insurance models validate using state disaster records and premium collections. FEMA validates against regulatory compliance standards. Different validation methods measuring different phenomena. Accuracy comparisons become nearly impossible.

California passed the nation's first testing requirements this month. Before that? Nothing. Homes miles from actual fires can have lead dust from burned materials settled in air ducts. Nobody was required to test for it or clean it.

Two-thirds of FEMA maps are over five years old. They show historical flooding, not future risk. Climate-driven rainfall patterns and sea level rise don't factor in. Property owners can hire engineers to shrink their mapped flood zone by half.

Washington, DC's inner city runs seventeen degrees hotter than surrounding areas. Low-income families live in dangerously hot homes at three times the rate of wealthy households. No disclosure exists for neighborhood heat risk or whether buildings trap heat.

Central Valley homes lost between $6,689 and $16,165 in value as groundwater pumping causes land to sink. Texas requires disclosure only if sellers already know they're in a subsidence district. No duty to investigate means most don't.

Carriers refuse coverage for homes within five hundred feet of water or documented erosion zones. Some use climate models to predict which properties might be underwater within a mortgage term. A new category of coastal real estate nobody will insure.

Wickenburg, Arizona's water district manager watches his aquifer drop steadily since 2018. People ask if the town will run out of water. "I tell them I don't know, and that's the honest answer. The models don't agree."