A global analysis of how human infrastructure squeezes sandy coasts - Scripts & Data

<strong>Abstract</strong> Coastal ecosystems provide vital services, including water storage, carbon sequestration, biodiversity, and coastal protection. Human disturbances, however, cause massive losses. The most direct impact is habitat destruction through infrastructure development, restricting the space available to coastal ecosystems and impeding their capacity to adapt to sea level rise by landward retreat – a phenomenon called ‘coastal squeeze’. While shoreline retreat is intensively studied, coastal congestion through infrastructure remains unquantified. Here we calculated the distance to the nearest human-made structure along 263,900 transects to show that infrastructure occurs at a 560-meter median distance from the shoreline worldwide. Moreover, we find that 18% of global shores harbour less than 100 m of infrastructure-free space, and that 14-17% of the unimpacted space may drown by 2100 according to sea level rise projections. Further analyses show that population density and gross domestic product explain 40-44% of observed squeeze variation, emphasizing the intensifying pressure imposed as countries develop and populations expand. Encouragingly, we find that nature reserves relieve squeezing by 3-5 times, illustrating their effectiveness. Yet, at present only 16% of world’s sandy shores has a protected status. We therefore argue that expansion of nature reserves could be key to preserving coastal resilience to sea level rise. ============================================== <strong>Methods</strong> The analyses rely on the following freely available datasets: Open Street Map: https://www.openstreetmap.org/#map=7/52.154/5.295 Global Urban Footprint: https://www.dlr.de/eoc/en/desktopdefault.aspx/tabid-9628/16557_read-40454/ GDP: https://data.worldbank.org/indicator/NY.GDP.PCAP.CD World population: https://data.humdata.org/dataset/worldpop-population-counts-for-world/resource/677d30ab-896e-44e5-9a31-05452bc3124b Protected areas: https://www.protectedplanet.net/en/thematic-areas/wdpa?tab=WDPA Shoreline: https://www.soest.hawaii.edu/pwessel/gshhg/ (coastline_L1) Projected shoreline change: https://data.jrc.ec.europa.eu/dataset/18eb5f19-b916-454f-b2f5-88881931587e In addition, we requested the sandy shoreline data from: Luijendijk et al. (2018) "The State of the World’s Beaches", Scientific Reports 8: 6641; https://www.nature.com/articles/s41598-018-24630-6 The deposited data contain 4 subfolders based on the separate analyses presented in the paper. In each subfolder you can find a Matlab script to run and an accompanying dataset to load. A readme file is included, which further explains the scripts and datasets.