Local US economies could take $68b hit from flooding next year: Study

WASHINGTON • US businesses stand to lose more than three million days of operations from flooding next year and will face worsening economic fallout in the coming decades as climate change fuels ever more extreme weather events, researchers said yesterday.

Next year's expected damage, based on estimated trends, translates to a nearly US$50 billion (S$68 billion) annual hit for local economies in cities from Miami to Pittsburgh, according to First Street Foundation, a non-profit group that maps climate risk.

Its researchers took a comprehensive look at the expected flood risk to businesses and local economies in the United States - a threat often underestimated amid a focus on flooded homes.

Dr Jeremy Porter, the group's head of research and development, said: "You talk about commercial activity, you're talking about the economic activity that underpins the entire community."

In total, local businesses could lose the equivalent of 3.1 million days of operations next year from floods - a number estimated to hit four million by 2052 as flood threats grow, the report said.

Researchers found that roughly 730,000 retail, office and multi-unit residential properties - with commercial units as well as homes - are at risk of projected flood damage today in the contiguous US.

High-risk metropolitan areas included not just Miami and New York - coastal spots - but also inland cities like Pittsburgh, sited at the confluence of three rivers.

Mr Steven Rothstein of Ceres, a US-based non-profit working to reshape economic systems to address climate and other risks, said: "You tend to think about the coasts, but it's very important we don't ignore rivers and streams."

The study calculated the economic fallout from flood risk by projecting expected damage and repair time for buildings, in part by digging into details such as which floor key equipment was located on. Getting such information into the public sphere can help individual property owners cut risks, said Mr Ibbi Almufti, a structural engineer with engineering firm Arup.

"Raising equipment out of the basement, for example, or hardening your exterior with flood walls," are among possible fixes, said Mr Almufti, whose company partnered with First Street Foundation on the report.

He said he was struck by the scale and growth of the anticipated threat and by rising damage in some particular areas. For example, Bay City, Texas - about 129km south and west of Houston - was projected to see a 5.8 per cent increase in the number of structures with damage over 30 years.

However, that small boost in numbers translated to a more than 900 per cent increase in estimated economic damages over that period. Even an extra 15cm of flooding on a more frequent basis can significantly boost average annual losses, Mr Almufti said.

Cities and municipalities are taking note and in some cases relying on businesses to help them update their own modelling and risk projections. For example, Florida's Broward county has worked with Jupiter, a company that maps climate risk, to develop 100-year municipal flood projections.

Many businesses are already acting on growing climate risks. Some major corporate headquarters and facilities - including Roper Hospital in Charleston, South Carolina - have made plans to relocate to lower their climate-related risks.

But more vulnerable populations can end up getting crowded out by firms looking to cash in on the least flood-threatened land, in a process known as climate gentrification.

Mr Rothstein said flood data and risk calculations are continually evolving, but that these cannot be an excuse for inaction on threats.

Already, "Dallas had two 100-year floods within four years - not 200 years", he noted. "The risk is not, gee, do you have perfect data? I think the biggest risk is doing nothing."

REUTERS