From Mother Jones news:
The report concludes that climate change is likely to expand vastly the size and costs of the 45-year-old government flood insurance program. Like previous government reports, it anticipates that sea levels will rise an average of four feet by the end of the century. But this is what's new: The portion of the US at risk for flooding, including coastal regions and areas along rivers, will grow between 40 and 45 percent by the end of the century. ... The report attributes only 30 percent of the increased risk of flooding to population growth; 70 percent is due to climate change.
Read more of that article here, or download a PDF of the full report here.