# RECORD 11ddac3108d5fcc806866635ea2276160f2ca53d # TITLE: Coastal armoring and sinking property values: the case of seawalls in California # YEAR: 2020.0 VENUE: Environmental Economics and Policy Studies DOI: 10.1007/s10018-020-00278-3 # AUTHORS: Arlan Brucal; John M. Lynham # PAGES: 23 CANDIDATE TABLE PAGES (1-based): [7, 9, 10, 15, 17, 18, 19] # ABSTRACT: Rising sea levels necessitate careful consideration of different forms of coastal protection but cost-benefit analysis is limited when important non-market social costs have not been measured. Seawalls protect individual properties but can potentially impose negative externalities on neighboring properties via accelerated beach loss. We conduct a hedonic valuation of seawalls in two coastal California counties: San Diego and Santa Cruz. We find no strong evidence to suggest that the presence of a seawall is positively correlated with the value of the home protected. However, we find that seawalls are strongly negatively correlated with the value of neighboring properties in Santa Cruz but not in San Diego county, suggesting that the effect of seawalls depend on certain geographical attributes. Our results are robust to accounting for the public-good nature of locational attributes and the potential spatial dependence of housing prices. Simulation reveals that doubling the extent of seawalls in San Diego and Santa Cruz could reduce property tax revenues by $7 million and $54 million, respectively. ===== PAGE 1 (score 7, numeric-paren 0, table-words 0, var-words 7) ===== Vol.:(0123456789) Environmental Economics and Policy Studies (2021) 23:55–77 https://doi.org/10.1007/s10018-020-00278-3 1 3 RESEARCH ARTICLE Coastal armoring and sinking property values: the case of seawalls in California Arlan Brucal1   · John Lynham2 Received: 10 September 2019 / Accepted: 4 May 2020 / Published online: 4 June 2020 © The Author(s) 2020 Abstract Rising sea levels necessitate careful consideration of different forms of coastal protec- tion but cost-benefit analysis is limited when important non-market social costs have not been measured. Seawalls protect individual properties but can potentially impose negative externalities on neighboring properties via accelerated beach loss. We con- duct a hedonic valuation of seawalls in two coastal California counties: San Diego and Santa Cruz. We find no strong evidence to suggest that the presence of a seawall is positively correlated with the value of the home protected. However, we find that seawalls are strongly negatively correlated with the value of neighboring properties in Santa Cruz but not in San Diego county, suggesting that the effect of seawalls depend on certain geographical attributes. Our results are robust to accounting for the public- good nature of locational attributes and the potential spatial dependence of housing prices. Simulation reveals that doubling the extent of seawalls in San Diego and Santa Cruz could reduce property tax revenues by $7 million and $54 million, respectively. Keywords  Seawalls · Hedonic valuation · Coastal erosion · Property values JEL Classification  H23 · Q26 · Q51 · Q54 Arlan Brucal: Brucal acknowledges support from the Grantham Foundation and the Economic and Social Research Council (ESRC) through the Centre for Climate Change Economics and Policy. John Lynham: Lynham acknowledges support from the Center for Ocean Solutions and valuable research assistance from Qingran Li. Electronic supplementary material  The online version of this article (https​://doi.org/10.1007/s1001​ 8-020-00278​-3) contains supplementary material, which is available to authorized users. * Arlan Brucal a.z.brucal@lse.ac.uk John Lynham lynham@hawaii.edu 1 Grantham Research Institute on Climate Change and the Environment, London School of Economics and Political Science, Houghton Street, London WC2A 2AE, UK 2 Department of Economics, University of Hawaii at Manoa, 2424 Maile Way, Saunders Hall 542, Honolulu, HI 96822, USA ===== PAGE 7 (score 30, numeric-paren 0, table-words 4, var-words 9) ===== 61 1 3 Environmental Economics and Policy Studies (2021) 23:55–77 (ERF) is reduced to zero. To compute this variable, the erosion rate at each prop- erty location is calculated first. Since in some areas erosion rates can be determined from historical records, while in others they are affected by protection devices such as seawalls, we applied the same method used in the Heinz Center’s erosion haz- ard report. A detailed description of this formulation is presented in Appendix B. A squared logarithm of Geotime is added to the model to test for a non-linear effect. Built Post-FIRM is an indicator variable for whether or not the home was built post the publication of a Flood Insurance Rate Map (FIRM) for the surrounding area. Post-FIRM homes typically have lower insurance premiums if they are built above base flood elevation levels, therefore we expect the coefficient on this variable to be positive. Table 1 presents summary statistics for all of our main variables. On the average, properties in Santa Cruz are generally more expensive compared to those in San Diego. This is probably due to bigger houses and lot sizes. Houses in San Diego are also situated in higher places and closer to the water, which implies that these houses are potentially in high cliffs above water (Griggs and Savoy 1985). The difference in Table 1   Summary statistics Source of basic data: The Heinz III Center for Science, Economics, and Management (Center 2000) San Diego Santa Cruz Mean SD Min Max Mean SD Min Max Price (’000, in 2014 US$) 588.56 412.20 66.15 3120.00 699.08 600.85 71.25 3120.00 Seawall (0–1) 0.18 0.38 0.00 1.00 0.19 0.39 0.00 1.00 Percent seawalled (%) 39.59 17.79 0.00 61.54 42.49 21.00 0.00 100.00 House size (sq. ft.) 1784.05 811.17 700.00 5000.00 2571.56 2377.86 450.00 22000.00 Lot size (sq. ft.) 5843.64 5019.31 863.00 28239.00 8032.56 4873.24 399.00 28106.00 Years since last trans- action 14.42 10.52 1.00 42.00 18.62 12.84 0.00 55.00 Years since built 40.09 19.86 2.00 109.00 44.78 20.56 1.00 104.00 Fireplace (0–1) 0.81 0.39 0.00 1.00 0.72 0.45 0.00 1.00 Waterfront (0–1) 0.47 0.50 0.00 1.00 0.44 0.50 0.00 1.00 Waterfront nourish- ment (1–0) 0.06 0.24 0.00 1.00 0.02 0.12 0.00 1.00 Beach nourishment (1–0) 0.13 0.34 0.00 1.00 0.05 0.21 0.00 1.00 Bedroom 2.93 1.09 1.00 6.00 3.19 1.47 1.00 12.00 Geotime 2289.42 6609.13 0.47 45772.00 4895.74 8636.80 55.96 46059.00 Elevation (ft.) 7801.26 4220.72 −12.30 10158.70 1327.22 3360.50 − 18.00 10086.40 Distance to water (ft.) 186.75 162.45 1.00 803.35 249.77 161.57 29.05 670.38 Beach width 81.21 286.96 0.00 3000.00 38.39 179.09 0.00 2000.00 Built Post-FIRM 0.05 0.21 0.00 1.00 0.07 0.25 0.00 1.00 Year of purchase 1985 10.52 1957 1998 1980 12.84 1944 1999 Observations 132 151 ===== PAGE 8 (score 19, numeric-paren 0, table-words 5, var-words 9) ===== 62 Environmental Economics and Policy Studies (2021) 23:55–77 1 3 this locational attribute should provide more insights on the effect of seawalls on inland property. In particular, seawalls in Santa Cruz should affect inland properties much more than they could in San Diego. The extent of seawalled properties are about the same for the two counties, which makes these two cases comparable. 3  Results 3.1  OLS results We start our analysis with an ordinary least squares (OLS) method using all the vari- ables listed in Table A.6. We did separate analysis for San Diego and Santa Cruz to account for  the potential difference in hedonic price functions between these two market segments. We also run combined observations from the two counties to formally test this difference by adding a San Diego indicator variable that turns on when the property is situated in San Diego County. Results are summarized in Table 2. For San Diego, we reject the null hypothesis of no correlation for only 4 var- iables. In particular, we find that price increases by about 0.50% as the size of a house increases by one percent.9 This translates to a marginal implicit price of house size by about $164/sq.ft.10 Lot size has smaller marginal implicit price, with houses being valued more by about $37 as lot size increases by sq.ft. Waterfront is surpris- ingly not significant. This is possibly due to fact that most houses in San Diego are situated in high cliffs above water and beach is not easily accessible. Surprisingly, homeowners value having a fireplace in their homes, considering that most areas of San Diego rarely require a fireplace for heating. This is possibly because we did not explicitly know whether it is outdoor or indoor fireplaces. Outdoor fireplaces may be associated with homeowners’ valuation of outdoor living, which makes this struc- tural attribute a worthy investment.11 In Santa Cruz, house size is positively correlated with housing prices. However, since houses in Santa Cruz are larger on the average, the implicit marginal price of house size is smaller at $135/sq.ft. The same observation holds true for lot size, with Santa Cruz houses being valued by $32 more per additional sq.ft. Waterfront, in contrast to San Diego, is significantly associated with higher housing prices in Santa Cruz. In particular, waterfront houses in Santa Cruz are valued more by about 40%, 9  We recognize that all of our regression coefficients should be interpreted as elasticities, although we remain silent on the direction of causality. See Gopalakrishnan et al. (2011) for a discussion of the endo- geneity problem in hedonic beach value models and for a potential solution. 10  We calculate marginal implicit price ($ per unit) for the logged variables as: where 훽k is the estimated coefficient of the regressor xk , and ̄xk and ̄p are the unconditional means of the regressor xk and the dependent variable p, respectively. Marginal Implicit Price = 𝛽k ̄xk × ̄p 11  The National Association of Realtors 2013 Home Features Survey reveals that 57% chose homes with at least one fireplace. ===== PAGE 9 (score 165, numeric-paren 138, table-words 1, var-words 7) ===== 63 1 3 Environmental Economics and Policy Studies (2021) 23:55–77 Table 2   Results from simple OLS Regression All variables Reduced model Reduced model Combined San Diego Santa Cruz Combined San Diego Santa Cruz Combined San Diego Santa Cruz Seawall (0−1) 0.099 0.216 0.100 0.114 0.223 0.068 0.079 0.216 −0.007 (0.130) (0.182) (0.206) (0.110) (0.159) (0.157) (0.107) (0.157) (0.146) Percent seawalled (%) −0.080*** −0.038 −0.111** −0.091*** −0.061 −0.100*** −0.088*** −0.065* −0.094*** (0.030) (0.045) (0.050) (0.024) (0.038) (0.028) (0.024) (0.038) (0.028) House size (sq. ft.) 0.516*** 0.498*** 0.523*** 0.496*** 0.455*** 0.480*** 0.494*** 0.460*** 0.504*** (0.113) (0.125) (0.163) (0.089) (0.105) (0.131) (0.088) (0.104) (0.129) Lot size (sq. ft.) 0.150** 0.370*** 0.057 0.133** 0.373*** 0.079 0.137*** 0.375*** 0.076 (0.061) (0.097) (0.073) (0.053) (0.089) (0.065) (0.053) (0.089) (0.063) Years since last transaction −0.387*** −0.392*** −0.375*** −0.374*** −0.379*** −0.355*** −0.372*** −0.380*** −0.359*** (0.040) (0.058) (0.057) (0.036) (0.055) (0.048) (0.036) (0.055) (0.047) Years since built −0.174* −0.134 −0.218 −0.064 −0.050 −0.106 −0.070 −0.052 −0.102 (0.095) (0.125) (0.174) (0.065) (0.099) (0.085) (0.065) (0.097) (0.087) Fireplace (0−1) 0.232*** 0.267*** 0.181 0.213*** 0.255** 0.187* 0.211*** 0.241** 0.191* (0.075) (0.096) (0.115) (0.074) (0.105) (0.104) (0.074) (0.103) (0.104) Waterfront (0−1) 0.290*** 0.165 0.333** 0.375*** 0.196 0.463*** 0.365*** 0.207 0.428*** (0.106) (0.119) (0.159) (0.088) (0.134) (0.117) (0.086) (0.133) (0.112) Waterfront nourishment (1−0) −0.147 0.147 −0.216 −0.270 0.118 −0.447** (0.232) (0.620) (0.234) (0.205) (0.582) (0.204) Beach nourishment (1−0) 0.056 −0.001 0.124 0.087 −0.205 0.209** (0.180) (0.456) (0.168) (0.137) (0.408) (0.104) Bedrooms −0.036 −0.066 0.032 (0.088) (0.116) (0.137) Geotime 0.008 −0.034 −0.001 (0.066) (0.322) (0.076) ===== PAGE 10 (score 51, numeric-paren 37, table-words 3, var-words 1) ===== 64 Environmental Economics and Policy Studies (2021) 23:55–77 1 3 Robust standard errors are in parentheses. *, **, ***Denote statistical significance at 10, 5 and 1% level. Source of basic data: The Heinz III Center for Science, Economics, and Management Table 2   (continued) Regression All variables Reduced model Reduced model Combined San Diego Santa Cruz Combined San Diego Santa Cruz Combined San Diego Santa Cruz Geotime squared −0.005 −0.005 −0.000 (0.005) (0.021) (0.007) Elevation (ft.) 0.013 −0.004 0.020 (0.016) (0.027) (0.023) Distance to water (ft.) −0.009 0.027 −0.023 (0.043) (0.109) (0.049) Beach width 0.015 0.019 0.013 (0.021) (0.031) (0.029) Built Post-FIRM −0.540** −0.580 −0.476 (0.239) (0.356) (0.401) San Diego (1−0) 0.132 −0.015 −0.013 (0.104) (0.076) (0.075) Constant 9.587*** 7.889*** 10.385*** 9.380*** 7.445*** 10.067*** 9.374*** 7.414*** 9.913*** (0.767) (1.402) (1.132) (0.652) (0.863) (0.961) (0.653) (0.866) (0.974) Observations 247 130 117 281 130 151 281 130 151 R-sq. 0.557 0.623 0.550 0.516 0.574 0.497 0.513 0.572 0.486 R-sq. (adj.) 0.522 0.566 0.473 0.496 0.538 0.461 0.497 0.544 0.457 ===== PAGE 11 (score 16, numeric-paren 0, table-words 4, var-words 8) ===== 65 1 3 Environmental Economics and Policy Studies (2021) 23:55–77 posting a marginal implicit price of more than $232,000.12 The existence of fire- place, while positive, is not significantly correlated with housing prices. Overall, we find no strong evidence to suggest that there are systematic differ- ences in housing prices between the two counties or market segmentation (Taylor 2003). Our OLS regression finds that the San Diego dummy, while positive, is statis- tically insignificant. We also performed Wald test for San Diego dummy and found the F-statistic insignificant, with the value of 1.60 and p value equivalent to 0.207. The variables indicating flooding and erosion risks (e.g.Geotime, Elevation) do not appear to be significantly correlated with property prices. This is true when we analyze housing prices in each county separately and after combining observations from the two counties. This is different from the findings in Kriesel and Friedman (2003). This could potentially be explained by the different nature of the shorelines between the two regions. Unlike the Atlantic and Gulf coast, much of the Pacific coastline consists of narrow beaches backed by steep cliffs. Cliff erosion is site spe- cific and episodic, which is often hidden by the low long-term average erosion rate. Only 45 observations in our entire sample have a Geotime less than 100 years. It is likely that erosion risk is not reflected in property prices till decades later. Although the low long-term erosion rate might reduce homeowners’ perceptions of the erosion threat to their properties, shoreline management policies can still affect house buyers’ awareness of erosion risk levels. Regarding the seawall indica- tors, we obtain remarkably similar results to Kriesel and Friedman (2003) and Krie- sel et al. (2005). The coefficient on Seawall is positive but not statistically significant in either county. The imprecision of this estimate relative to Kriesel and Friedman (2003) could be due to our smaller sample size. We evaluate the effect of seawalls on housing prices using combined samples to increase the sample size and observe same result. Meanwhile, we notice a significant negative effect of Percent Seawalls on prop- erty prices in Santa Cruz. This suggests that property owners in the county are worse off as a result of extensive coastal armoring. Furthermore, our coefficient of −0.11 is more than three times larger than the −0.03 found by Kriesel and Friedman (2002). This suggests that, as the percentage of waterfront coastal armoring in a community increases by 100%, the associated value of a house located on the Santa Cruz coast drops by $77,597. In contrast, we do not find any strong evidence to suggest that the extent of armored coastline in San Diego has an effect on property values. If there is an effect, house values in San Diego declines by about $22,365 if the share of waterfront coastal armoring in a community increases by 100%. Interestingly, our estimate falls within the ballpark of Kriesel and Friedman (2003) who found that for the same percentage increase in coastal armoring, house prices on the Atlantic and Gulf coasts drop by $41,091 in 2014 dollars. 12  For dummy variables, the calculated marginal implicit price is expressed as: where 훽k and p are as previously defined. (5) Marginal Implicit Price = (e𝛽k −1) × ̄p ===== PAGE 15 (score 16, numeric-paren 10, table-words 2, var-words 1) ===== 69 1 3 Environmental Economics and Policy Studies (2021) 23:55–77 horizontal axis and the average prices of neighboring houses weighted by the spatial lag vector 퐖 in the vertical axis. We assume that the degree of spatial dependence of a particular house is inversely related to the geographic distance between the two properties. That is, We find evidence of positive spatial dependence for houses located in Santa Cruz. The Moran statistic is 0.0867 and is statistically significant at 5% level. In contrast, there is no strong evidence to suggest that housing prices in San Diego are spatially dependent. We formally test for the presence of global spatial autocorrelation by calculating Moran’s I (Moran 1950) and Geary c (Cliff and Ord 1970). We then determine the significance of these statistics following the procedure suggested by Pisati (2001). Table 3 summarizes the results. The tests confirm our graphical approach suggest- ing no strong spatial dependence of house prices in San Diego. In contrast, there is strong evidence of spatial autocorrelation of house prices in Santa Cruz. The spatial autocorrelation persists even if we combined the two datasets. 3.2.2  Hedonic prices with spatial dependence With an indication of potential spatial dependence, we re-estimate Eq. (2) using data on Santa Cruz county house prices. This time, we relax the assumption that 휆 and 휌 are both zero. We estimate parameters based on models with spatial dependence in a maximum likelihood framework using the procedure suggested by Drukker et al. (7) 퐖= ⎛ ⎜ ⎜ ⎜ ⎜⎝ 0 w1,2 w1,3 … w1,n w2,1 0 w2,3 … w2,n w3,1 w3,2 0 … w3,n ⋮ ⋮ ⋮ ⋱ ⋮ wn,1 wn,2 wn,3 … 0 ⎞ ⎟ ⎟ ⎟ ⎟⎠ wi,j = 1 dij . Table 3   Tests for global spatial autocorrelation The estimated standard deviation of each statistic are in parentheses. *,**,***Represents significance at 10, 5 and 1%, respectively San Diego Santa Cruz Combined Distance of nearest neighbor (in kms) Mean 1.279 0.042 Min 0.931 0.006 Max 3.336 0.239 Moran’s I 0.023 0.087** 0.054* (0.049) (0.037) (0.022) Geary c 0.943 0.900** 0.924** (0.051) (0.040) (0.024) ===== PAGE 16 (score 18, numeric-paren 0, table-words 6, var-words 6) ===== 70 Environmental Economics and Policy Studies (2021) 23:55–77 1 3 (2015). We employ different specifications to potentially account for different forms of spatial autocorrelation, namely spatial lag model, spatial error model and the spa- tial ARAR(1,1,) model.17 Then, for each model, we run three different specifications similar to the simple OLS regression in which we start with all the variables and drop some of them to slightly increase our sample. We do this to test the stability of our estimates. Results are presented in Table 4. We start the analysis by looking at the estimated spatial autocorrelation param- eters. We find no strong evidence to suggest that there exists spatial autocorrela- tion. In particular, we fail to reject the null hypotheses that (1) 휆= 0, 휌≠0 ; (2) 휆≠0, 휌= 0 ; and (3) 휆≠0, 휌≠0 in Eq. (6).18 The estimated effect of changes in the variables of interest, even after account- ing for potential spatial dependence, remains robust and consistent with our base- line results. The coefficient remains insignificant for the indicator variable Seawall. Nonetheless, the coefficient for the extent of coastline armoring (Percent Seawalls), remains negative albeit slightly smaller and statistically significant. This confirms our earlier result that as the percentage of waterfront coastal armoring in a beach community increases, the associated value of houses located in San Diego and Santa Cruz drops significantly. Moreover, our estimates remain stable across differ- ent forms of assumed spatial dependence and under different sets of controls, thus increasing our confidence on the robustness of the results. 4  Discussion We find that the sales price of a house located within 1,000 feet of the coast in San Diego and Santa Cruz counties is correlated with its structural characteristics and the shoreline management policies taken in the community. Although seawalls pro- tect coastal structures from erosion damages, the negative coefficient on Percent Seawalls calls for attention to the welfare impacts of coastal armoring on waterfront and non-waterfront households. Using our baseline estimates, we predicted the potential  change in total hous- ing values for the two counties when the share of those that are protected by sea- walls increases by a certain percentage (see Table  5). Results suggest that dou- bling the current level of properties protected by seawalls may be associated with a $20,954.16 drop in the resale value of an average coastal home in San Diego that is protected by seawalls. For those that are not protected by seawalls, the magnitude 17  Thanks to an anonymous referee, we recognized that the estimation of a SARAR model may intro- duce more problems than solving them. Nonetheless, the employment of different specifications, includ- ing the SARAR, is meant to show that our estimates, particularly on seawall protection, are consistent and robust over different specifications of spatial dependence. We refrain to interpret the actual estimates due to uncertainties in the type of spatial dependence. 18  We also perform diagnostic tests for spatial dependence in an OLS framework after estimating Eq. (2), following the procedure as suggested by Pisati (2001). Results are summarized in Table A.8. We find no strong evidence to suggest that there is spatial dependence amongst observed housing prices in each county. ===== PAGE 17 (score 161, numeric-paren 134, table-words 1, var-words 7) ===== 71 1 3 Environmental Economics and Policy Studies (2021) 23:55–77 Table 4   Results for models with spatial dependence Spatial lag model Spatial error model Spatial ARAR(1,1) model (1) (2) (3) (1) (2) (3) (1) (2) (3) Seawall (0−1) 0.094 0.068 −0.008 0.103 0.060 −0.011 0.084 0.046 −0.026 (0.161) (0.138) (0.128) (0.163) (0.136) (0.126) (0.157) (0.132) (0.123) Percent seawalled (%) −0.098* −0.100** −0.093** −0.112** −0.100*** −0.094** −0.081* −0.090** −0.084** (0.053) (0.041) (0.041) (0.054) (0.037) (0.038) (0.047) (0.035) (0.035) House size (sq. ft.) 0.496*** 0.480*** 0.502*** 0.519*** 0.484*** 0.508*** 0.472*** 0.468*** 0.489*** (0.155) (0.117) (0.118) (0.155) (0.114) (0.115) (0.149) (0.112) (0.113) Lot size (sq. ft.) 0.056 0.079 0.076 0.056 0.073 0.071 0.064 0.064 0.062 (0.075) (0.060) (0.059) (0.077) (0.058) (0.058) (0.070) (0.055) (0.055) Years since last transaction −0.379*** −0.355*** −0.360*** −0.374*** −0.358*** −0.363*** −0.382*** −0.363*** −0.367*** (0.057) (0.053) (0.053) (0.058) (0.053) (0.053) (0.057) (0.053) (0.052) Years since built −0.196 −0.106 −0.100 −0.210* −0.113 −0.107 −0.212* −0.102 −0.097 (0.124) (0.080) (0.081) (0.127) (0.079) (0.080) (0.125) (0.078) (0.079) Fireplace (0−1) 0.176 0.187* 0.191* 0.183 0.177 0.184* 0.142 0.165 0.171 (0.116) (0.108) (0.108) (0.117) (0.108) (0.108) (0.119) (0.108) (0.108) Waterfront (0−1) 0.333** 0.463*** 0.426*** 0.326** 0.480*** 0.441*** 0.371*** 0.470*** 0.434*** (0.131) (0.101) (0.099) (0.136) (0.100) (0.098) (0.133) (0.096) (0.094) Waterfront nourishment (1−0) −0.208 −0.446* −0.216 −0.458* −0.200 −0.453* (0.263) (0.251) (0.264) (0.252) (0.264) (0.251) Beach nourishment (1−0) 0.132 0.209 0.127 0.220 0.128 0.196 (0.207) (0.166) (0.208) (0.163) (0.203) (0.163) Bedrooms 0.033 0.028 0.054 (0.134) (0.136) (0.132) Geotime 0.021 0.010 −0.007 (0.080) (0.093) (0.076) ===== PAGE 18 (score 61, numeric-paren 47, table-words 2, var-words 1) ===== 72 Environmental Economics and Policy Studies (2021) 23:55–77 1 3 Table 4   (continued) Spatial lag model Spatial error model Spatial ARAR(1,1) model (1) (2) (3) (1) (2) (3) (1) (2) (3) Geotime squared −0.002 −0.001 −0.000 (0.006) (0.007) (0.006) Elevation (ft.) 0.027 0.020 0.036* (0.021) (0.020) (0.020) Distance to water (ft.) −0.033 −0.030 −0.009 (0.049) (0.059) (0.049) Beach width 0.010 0.013 0.005 (0.022) (0.022) (0.023) Built post-FIRM −0.426 −0.449 −0.512* (0.290) (0.312) (0.302) Constant 8.372*** 10.034*** 9.640*** 10.398*** 10.114*** 9.959*** 6.603*** 8.362*** 8.102*** (2.221) (1.904) (1.895) (1.043) (0.803) (0.809) (2.470) (2.122) (2.077) Lambda 0.156 0.003 0.022 0.294 0.146 0.155 (0.152) (0.136) (0.135) (0.181) (0.166) (0.162) Rho 0.056 −0.134 −0.107 −0.341 −0.312 −0.294 (0.250) (0.204) (0.201) (0.339) (0.287) (0.280) Observations 117 151 151 117 151 151 117 151 151 Degrees of Freedom (model) 17 10 8 17 10 8 17 10 8 Log-likelihood −71.103 −106.390 −107.966 −71.586 −106.167 −107.833 −70.669 −105.846 −107.458 Chi-sq. 125.754 138.532 132.654 134.338 155.262 146.471 123.693 128.271 123.748 Robust standard errors are in parentheses. *, **, ***Denote statistical significance at 10, 5 and 1% level ===== PAGE 19 (score 26, numeric-paren 0, table-words 2, var-words 8) ===== 73 1 3 Environmental Economics and Policy Studies (2021) 23:55–77 is larger at $22,365. Overall, the said increase in the share of protected properties translates to more than $718 million reduction in the value of affected houses in the county. In terms of property tax revenues, a very crude back-of-the-envelope Table 5   Potential effect of increasing the share of waterfront households protected by seawalls I. San Diego County has 70 miles of coastline. Based on a very conservative estimate of housing density (4 homes per acre), this means that there are approximately 33,939 homes within 1,000 feet of the shore- line. 42% of these homes are currently protected by seawalls. Property tax in San Diego County is a little more than 1%. II. Santa Cruz County has 29 miles of coastline. Based on an even more conservative estimate of housing density (2 homes per acre), this means that there are approximately 7,030 homes within 1,000 feet of the shoreline. 40% of these homes are currently protected by seawalls. Property tax in Santa Cruz County is a little more than 1%. III. The change in price for seawalled properties is calculated using the estimated coefficients of the Sea- wall and Percent Seawall in our baseline model (i.e., OLS including all variables). The unconditional mean property price for each county is used as the base price ($588,000 for San Diego and $699,000 for Santa Cruz.). For non-seawalled properties, we just used the coefficient for Percent Seawall % Change in seawalls (from current mean) Change in price No. of affected houses Total effect Revenue loss (in $) (in $) Seawalled Non-seawalled (in ’000$) (in ’000$) San Diego 1.00 10.47 −223.65 14,397 19,542 −4,219.92 −42.20 5.00 7.90 −1,118.26 14,967 18,972 −21,097.37 −210.97 10.00 −95.32 −2,236.53 15,680 18,259 −42,331.75 −423.32 20.00 −635.10 −4,473.06 17,105 16,834 −86,161.88 −861.62 30.00 −1,619.35 −6,709.58 18,531 15,408 −133,391.07 −1,333.91 40.00 −3,048.07 −8,946.11 19,956 13,983 −185,919.98 −1,859.20 50.00 −4,921.25 −11,182.64 21,382 12,557 −245,649.31 −2,456.49 60.00 −7,238.90 −13,419.17 22,807 11,132 −314,479.74 −3,144.80 70.00 −10,001.02 −15,655.70 24,232 9,707 −394,311.94 −3,943.12 80.00 −13,207.60 −17,892.22 25,658 8,281 −487,046.53 −4,870.47 90.00 −16,858.64 −20,128.75 27,083 6,856 −594,584.26 −5,945.84 100.00 −20,954.16 −22,365.28 28,509 5,430 −718,825.86 −7,188.26 Santa Cruz 1.00 −0.74 −775.98 2,840.12 4,189.88 −32,533.71 −325.34 5.00 −158.54 −3,879.89 2,952.60 4,077.40 −162,879.83 −1,628.80 10.00 −704.13 −7,759.79 3,093.20 3,936.80 −327,267.40 −3,272.67 20.00 −2,956.45 −15,519.58 3,374.40 3,655.60 −667,096.04 −6,670.96 30.00 −6,756.96 −23,279.37 3,655.60 3,374.40 −1,032,546.40 −10,325.46 40.00 −12,105.67 −31,039.15 3,936.80 3,093.20 −1,436,679.04 −14,366.79 50.00 −19,002.57 −38,798.94 4,218.00 2,812.00 −1,892,554.72 −18,925.55 60.00 −27,447.66 −46,558.73 4,499.20 2,530.80 −2,413,233.60 −24,132.34 70.00 −37,440.95 −54,318.52 4,780.40 2,249.60 −3,011,776.64 −30,117.77 80.00 −48,982.43 −62,078.30 5,061.60 1,968.40 −3,701,244.16 −37,012.44 90.00 −62,072.11 −69,838.09 5,342.80 1,687.20 −4,494,696.64 −44,946.97 100.00 −76,709.97 −77,597.88 5,624.00 1,406.00 −5,405,194.88 −54,051.95 ===== PAGE 20 (score 7, numeric-paren 0, table-words 0, var-words 7) ===== 74 Environmental Economics and Policy Studies (2021) 23:55–77 1 3 calculation suggests that this increase would cost the government $7 million in terms of revenue loss and the discounted present value of this annual loss is $143 million.19 For Santa Cruz County, the potential effect of increasing the current share of seawalled properties by 100% is significantly greater, reaching to about a $77,000 decline in home resale values for protected properties. For non-seawalled proper- ties, the effect is about similar at $78,000. This implies that there is no positive net benefit of putting up an additional seawall from the current level. The increase in the seawalled-properties is associated with the loss in the total value of coastal homes in the county by more than $5.4 billion. This translates to a government revenue loss of about $54 million, which is equivalent to a discounted present value of about $1.08 billion. Although our estimates are large, the associated welfare impacts are consist- ent with the existing literature. Our findings are in line with Kriesel and Friedman (2003) and Kriesel et al. (2005) who find negative, albeit smaller, effects on prop- erty prices. Landry et al. (2003) also found a negative effect, but their estimated effect was statistically insignificant. However, their contingent valuation study strongly suggests that beachgoers do not like beaches with seawalls. The existing literature suggests that our estimates might even be underestimated. Gopalakrishnan et al. (2011) correct for endogeneity bias and find that the beach width effect on property prices is almost five times larger. Furthermore, they find that the long- term net value of coastal residential property can fall by as much as 52% when the erosion rate triples. To the extent that seawalls can potentially double or triple erosion rates on neighboring non-protected properties, our estimates are very much in line with their results. Our paper does not come without limitations. Aside from potential measurement problems associated with the survey-based price variable and the inability to control for unobserved systematic patterns across beach communities, our study may also be confounded by the potential immunity of the property market to climate risks, which may be coupled with households’ potential downward bias against these risks. To be more precise, if property buyers underestimate the risk of floods/erosion, then the benefits of seawalls will be vastly undervalued while the negative consequences would remain. Moreover, we find that variables indicating flooding and erosion risks are not significantly correlated with property prices, which could indicate that home buyers are myopic. Another possibility is that home buyers assess the risk accurately but that it is quite low or even non-existent. Both possibilities could be because there were no flood episodes in the study areas in the years prior to the survey. Most of the prior flood episodes were in Northern California. There has been no major impacts in Central California until 2017 when Hurricane Marie caused flooding in the region. Even in the absence of flooding and erosion, more recent information of pro- gressing climate change, climate change reporting, and extreme events might have 19  Property tax in San Diego County is a little more than 1%. Using the annual discount rate of 5%, an infinite stream of annual losses of $7.188 million would be $7.188 m/0.05 = $143.765 m.