Tropical-cyclone damage now runs about $26 billion a year globally, according to a study published in January in the journal Nature Climate Change. By 2100, increases in population and wealth as economies grow could push that number to $56 billion a year, assuming little or no effort to adapt to the hazard.
Throw global warming into the mix and the number grows to $109 billion a year, the researchers calculate. Most of that added burden falls on North America, where, absent efforts to adapt to the changes, damage could range from $60 billion to $70 billion a year – roughly double the rate by 2100 that assumes today's climate.
Along the US East Coast, where Sandy and last year's hurricane Irene left chaos in their wakes, a perfect storm of rising sea levels and coastal development is brewing. Forty-two percent of the dry land up to one meter above sea level is already developed, and another 15 percent is slated for partial or complete development, according to a survey of state and local coastal development agencies in the region conducted three years ago by the US Environmental Protection Agency.
If communities and developers follow through on those plans, that would bring to nearly 60 percent the proportion of dry-land coast below one meter above sea level with more people and high-priced assets in harm's way. In the process, wetlands seaward of these developed areas would have no place to migrate as the sea level rises, leaving engineered barriers as the only protection from surge flooding.