According the study, the size of the nation's flood plains is expected to grow by 40 or 45 percent over the next 90 years, which is scheduled to be released later this summer.
That prediction envisions waves of seawater pushing deeper inland during strengthening storms as oceans rise between 0.75 and 1.9 meters by the year 2100. In river valleys and other low-lying flow ways, more rainwater could routinely reach onto areas where current flooding is rare.
Stretching the flood plains could encircle millions of new homes and businesses and expand the National Flood Insurance Program (NFIP) beyond its current volume of 5.6 million policies that protect property valued at $1.2 trillion from water damage. The study estimates that the program's policies could double in number by century's end.
Those results pushed Mark Crowell, a geologist with the Federal Emergency Management Agency, to tell coastal professionals attending a conference in New York last week that the findings establish "a need for FEMA to incorporate the effects of climate change more directly into various aspects of the NFIP."
That would mark a major policy change for the program, which has not explicitly accounted for rising temperatures and its accompanying byproducts, despite the impacts that climate change could have on flooding. Environmental advocates have sought for several years to expand FEMA's focus on historical flood levels to include higher water crests predicted for the future. Crowell said the study will not recommend including climate policies in the program.
Yet his presentation provided a glimpse into the conclusions of a project that was launched in 2008 -- when climate acceptance was at a high -- and has faced delay after delay. The study is more than a year off target. It's unclear what's causing the lag, but in 2009, a principal researcher joked that the challenges associated with applying current climate science to an insurance program are "not what a sensible person should do."
The results are bound to stir controversy in Congress, where some lawmakers might use the findings to advance climate adaptation policies like enhanced building codes or to prohibit development in flood-prone areas. Others would likely see those provisions as meddlesome restrictions on economic development -- and the tax revenue and jobs associated with it.
Rep. Shelley Moore Capito (R-W.Va.), a senior member of the House Financial Services Committee, which oversees flood insurance, said FEMA could find it "difficult" to convince congressional Republicans that the study conveys crucial challenges to the program.
In part, that's because the study relies on research by the Intergovernmental Panel on Climate Change (IPCC), which many Republicans view with skepticism, and by the U.S. Climate Change Science Program.
"I think there's enough people who are unconvinced about the true direction of climate change, [like] the impacts of it and how drastic it will be," Capito said, asserting that IPCC science has been "challenged."
But flood insurance experts were struck by the sheer size of the potential flood plain expansion, which could increase the amount of land prone to flooding by almost half of its current size.
"It's a big number," said Michael Buckley, a former FEMA official who works on flood issues.
Still, he noted that the rate of growth will be relatively small over 90 years. The program, he believes, can be fortified through better flood plain practices. Those could include revised "setbacks," which prohibit development within reach of rising oceans, and higher "freeboard" standards to elevate homes above minimum flood levels.
FEMA could encourage communities to adopt those standards by offering insurance discounts, Buckley said.
Others' warnings unheeded
When the report becomes public, it will perhaps mark FEMA's loudest warning about climate impacts on the sprawling insurance program, which dived deeply into debt during Hurricane Katrina in 2005. Its deficit stands now at more than $17 billion.
Earlier calls went largely unanswered by Congress and policymakers. The first warning came 20 years ago, when FEMA undertook a congressionally directed study on sea level rise, reviewing impacts of 1- to 3-foot increases.
Later in the 1990s, the agency studied future coastal erosion, which is enhanced by rising seas. Congress, facing opposition from developers, decided more research was needed, culminating in a major report by the Heinz Center. It recommended that Congress require FEMA to make maps of future coastal erosion and raise insurance rates to reflect rising risk.
The newest alert should be heeded, says David Maurstad, who ran the insurance program under President George W. Bush.
"We've got to start managing these issues now. We can't wait for that to happen," he said of the rising damage associated with climate change. "We can't let the built environment continue to increase in these risky areas."
He and others believe the future report strengthens calls to raise FEMA's standard of riskiness. Currently, most mortgage banks require home buyers to obtain flood insurance if the house is in a flood plain that has a 1 percent annual chance of being inundated, also known as the 100-year flood.
The boundaries for that flood zone should be expanded, many experts say, to compensate for higher water levels driven by climate change. That could also require homes now outside of the 1 percent flood plain to be hardened against water damage.
An end to unbridled building?
The report will also warn Congress that flood insurance rates could rise by as much as 70 percent by 2100, Crowell told the conference. That could have the dual effect of strengthening the program against rising risk, while also discouraging people from living in flood plains.
David Conrad, a water resource specialist who until recently worked for the National Wildlife Federation on flooding policy, expressed hope that the report could help stem the flow of people to shorelines and seacoasts.
"Hopefully, [officials] will begin to think about and anticipate where we are developing and redeveloping after major events," he said.
In insurance circles, the expansion of new development is the dominant notion behind rapidly rising financial losses from increasingly violent weather.
The industry acknowledges the spike in tornadoes, flooding, hurricanes and other events, but many officials see population shifts and new construction as the causes for losses: There are more assets to be damaged.
The FEMA report argues against that. Its results claim that climate change is responsible for 70 percent of the flood plain increase. The remaining 30 percent stems from increased development.
But Crowell, perhaps sensing a cool welcome for the report, described a challenging future for the insurance program even if the report's findings prove overblown.
"Even if future climate change is minimal, even if any of you out there don't believe in climate change, future flooding will increase anyways because population growth will lead to increase in development, which will lead to an increase in impermeability, which will in turn lead to an increase in flooding," he told the crowd.
"The NFIP will continue to grow."