Replenishing eroded beaches may prevent cities from properly adapting to climate change

Sunny Isle. The beaches of South Florida are already being replenished by the authorities. Image: Getty.

Coastal communities around the world are struggling to adapt to rising sea levels and increasingly severe coastal storms. In the United States, local governments are making investments to reduce those risks, such as protecting shorelines with seawalls, “nourishing” eroded beaches by adding sand and rerouting or redesigning roads and bridges.

In the short run, spending public money this way is economically rational. But in the long run, many people who live near coastlines will probably have to relocate as seas continue to rise.

We have studied this problem by combining insights from our work in economics, coastal geomorphology and engineering. As we have explained elsewhere, short-term actions to adapt to coastal flooding can actually increase risks to lives and property. By raising the value of coastal properties, these steps encourage people to stay in place and delay decisions about more drastic solutions, such as moving inland.

Keeping millions in harm’s way

According to recent estimates, a one-foot increase in sea levels will put about 1m people in the United States at risk, and 3 feet will threaten about 4m people. Global sea levels currently are projected to rise 0.5 to 2.1 feet by 2050 and 1.0 to 8.2 feet by 2100.

As we see it, market forces and public risk reduction policies interact in unexpected ways, reducing incentives for communities to make long-term plans for retreating from the shore. Nourishing beaches and building seawalls signal to individuals and businesses that their risks are lower. This makes them more likely to build long-lasting structures in risky areas and renovate and maintain existing structures. As a result, their property values increase, which reinforces economic and political arguments for more risk-reduction engineering.

To illustrate this pattern, we compared a sample of houses in Nags Head and Kitty Hawk, North Carolina, two popular beach towns less than 10 miles apart on North Carolina’s Outer Banks. When we consulted county tax appraisal values, Nags Head beaches had routinely received sand from beach nourishment, whereas Kitty Hawk beaches had not. On average, homes in our Nags Head sample were worth over $1m, while homes in the Kitty Hawk sample were worth about $200,000.

Other researchers have found that in some locations, the threat of rising seas is eroding coastal property values. But this tends to be true for properties that are viewed as highly vulnerable – for example, homes that have already flooded. In contrast, homes that are elevated or have other flood-proofing features tend to have much higher values, so they are perceived as assets.


Subsidising risky choices

Some amount of risk reduction makes sense. If people who benefited paid its full cost, and everyone involved understood how imminent the risk was and how much engineering solutions would cost, then market forces would likely produce reasonably efficient solutions.

As an example, flood-prone Norfolk, Virginia recently adopted an ordinance requiring almost all new homes and many major renovations to be elevated and include other flood-proofing features. This approach will help to price flood protection into the cost of homes and will tend to reduce demands to directly subsidise protective engineering, flood insurance and post-disaster assistance.

In our view, such solutions are a move in the right direction. But they will not break the positive feedback loop we describe as long as other public policies continue to skew perceptions of the long-term viability of coastal communities.

Engineering projects to slow shoreline retreat and reduce flooding generally receive smaller subsidies now than in past decades, but many communities still benefit. For example, beach nourishment in Ocean City, Maryland is cost-shared between the federal government, which pays about half, and state and local agencies. The Federal Emergency Management Agency helps pay to rebuild homes and public buildings damaged in major disasters. And allowing people to deduct local taxes on their federal tax forms partly subsidises local tax financing for risk reduction.

Beach nourishment started at New York’s Coney Island a century ago. But with the sheer volume of sand needed to keep up with sea level rise, its costs could outweigh its benefits within a few decades.

Inaccurate perceptions of risk

Information and uncertainty are larger problems. Many coastal residents do not perceive medium- and long-term climate risk to be as serious as the scientific consensus suggests. Moreover, scientists are still analysing how fast sea levels are likely to rise. Future storm frequency is uncertain, and could be affected by changes in global greenhouse gas emission trends.

On the positive side, engineering innovations such as designing storm-resistant homes could become more effective. But existing approaches like beach nourishment are likely to become more expensive as sand resources diminish and more communities compete for them. And growing uncertainty is likely to increase near-term demand for risk reduction engineering.

The most critical time for adaptation decisions is immediately after a storm or flood. Faced with expensive repairs or rebuilding, property owners face higher costs to return to the status quo. But if homeowners expect that public resources will be spent to protect them against future disasters, they are less likely to consider making big changes.

Federal or state financial rebuilding assistance creates a similar bias. If that money were used to subsidise relocation or other drastic adaptive actions, rebuilding patterns would be different. So far, however, programs for buying out flood-damaged properties have been largely unsuccessful. Many factors, including residents’ level of experience with disaster recovery and financial concerns, can make people unwilling to consider relocating.

Incentives to think long-term

There is no perfect formula for balancing near-term climate-proofing against more drastic steps to move people away from the coasts. But we believe that when communities focus excessively on reducing near-term threats, they risk inhibiting the successful adaptation that they are trying to promote.

We have three suggestions for breaking this cycle. First, local land use policies could be designed to discourage rebuilding homes to similar or higher property values after damage from storms. Second, communities could put increasing emphasis on adaptive engineering and large-scale planning practices – for example, sunsetting beach nourishment projects when sea level rise reaches some preannounced level.


Finally, adaptation decisions could be planned and implemented at a multi-jurisdictional level, rather than town by town. This approach would help to avoid “rich towns get richer” dynamics that can develop when wealthier jurisdictions deploy sand resources and other protective measures in a way that reduces their own risk while ignoring or heightening threats to nearby locations.

Change is coming to coasts around the world. We believe that broader understanding of how markets and public policy interact is essential to minimise the social and economic costs of this change.

The Conversation

Andrew G. Keeler, Professor of Economics and Program Head, Public Policy and Coastal Sustainability, UNC Coastal Studies Institute, East Carolina University; Dylan McNamara, Professor of Physics and Physical Oceanography, University of North Carolina Wilmington, and Jennifer Irish, Professor of Civil and Environmental Engineering, Virginia Tech.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

What's actually in the UK government’s bailout package for Transport for London?

Wood Green Underground station, north London. Image: Getty.

On 14 May, hours before London’s transport authority ran out of money, the British government agreed to a financial rescue package. Many details of that bailout – its size, the fact it was roughly two-thirds cash and one-third loan, many conditions attached – have been known about for weeks. 

But the information was filtered through spokespeople, because the exact terms of the deal had not been published. This was clearly a source of frustration for London’s mayor Sadiq Khan, who stood to take the political heat for some of the ensuing cuts (to free travel for the old or young, say), but had no way of backing up his contention that the British government made him do it.

That changed Tuesday when Transport for London published this month's board papers, which include a copy of the letter in which transport secretary Grant Shapps sets out the exact terms of the bailout deal. You can read the whole thing here, if you’re so minded, but here are the three big things revealed in the new disclosure.

Firstly, there’s some flexibility in the size of the deal. The bailout was reported to be worth £1.6 billion, significantly less than the £1.9 billion that TfL wanted. In his letter, Shapps spells it out: “To the extent that the actual funding shortfall is greater or lesser than £1.6bn then the amount of Extraordinary Grant and TfL borrowing will increase pro rata, up to a maximum of £1.9bn in aggregate or reduce pro rata accordingly”. 

To put that in English, London’s transport network will not be grinding to a halt because the government didn’t believe TfL about how much money it would need. Up to a point, the money will be available without further negotiations.

The second big takeaway from these board papers is that negotiations will be going on anyway. This bail out is meant to keep TfL rolling until 17 October; but because the agency gets around three-quarters of its revenues from fares, and because the pandemic means fares are likely to be depressed for the foreseeable future, it’s not clear what is meant to happen after that. Social distancing, the board papers note, means that the network will only be able to handle 13 to 20% of normal passenger numbers, even when every service is running.


Shapps’ letter doesn’t answer this question, but it does at least give a sense of when an answer may be forthcoming. It promises “an immediate and broad ranging government-led review of TfL’s future financial position and future financial structure”, which will publish detailed recommendations by the end of August. That will take in fares, operating efficiencies, capital expenditure, “the current fiscal devolution arrangements” – basically, everything. 

The third thing we leaned from that letter is that, to the first approximation, every change to London’s transport policy that is now being rushed through was an explicit condition of this deal. Segregated cycle lanes, pavement extensions and road closures? All in there. So are the suspension of free travel for people under 18, or free peak-hours travel for those over 60. So are increases in the level of the congestion charge.

Many of these changes may be unpopular, but we now know they are not being embraced by London’s mayor entirely on their own merit: They’re being pushed by the Department of Transport as a condition of receiving the bailout. No wonder Khan was miffed that the latter hadn’t been published.

Jonn Elledge was founding editor of CityMetric. He is on Twitter as @jonnelledge and on Facebook as JonnElledgeWrites.