Public willingness to pay for hybrid blue-green infrastructure: Evidence from the Clyde and Forth Estuaries, Scotland

Nature-based solutions are increasingly recognised as climate-resilient strategies for coastal climate adaptation. This study estimates public willingness to pay (WTP) for the creation of hybrid blue-green infrastructure in place of vacant and derelict land in the Clyde and Forth estuaries, using a contingent valuation method with a payment card format. Tobit and interval regression models were used to evaluate the effects of socioeconomic, attitudinal, and consequentiality variables on WTP. Modelled mean annual household WTP was £84.95 (95% CI:£78.82-£91.13) for the Clyde and £86.01 (95% CI: £80.51-£91.58) for the Forth, with corresponding conservative lower-bound estimates of £38.91 (95% CI: £34.25-£43.57) and £41.22 (95% CI: £36.95-£45.50), respectively. No statistically significant difference in WTP was observed between regions (p=0.473), indicating no evidence of systematic regional differences in stated WTP within the study sample. A split-sample methodology was used to assess alternative status quo framings, vacant and derelict land versus residential mixed-use development. No statistically significant difference in WTP was detected between the two framings (p=0.084), although this result does not establish that preferences are invariant to baseline conditions. Key predictors included income, environmental awareness, and membership of an environmental body or organisation. Sensitivity analysis showed that WTP estimates remained positive when protest responses were retained as zero-WTP observations, although the estimated magnitude declined. When aggregated to the Central Belt of Scotland, the results indicate substantial support for hybrid blue-green infrastructure, while population-level extrapolation should be interpreted in light of sample representativeness and protest-response classification. These findings provide supporting evidence that estuarine restoration delivers valued public benefits and can play an important role in long-term coastal resilience strategies. The methodology is applicable at the national scale, incorporating relevant coastal features, and could be applied elsewhere to assess public preferences and support climate-resilient policy.