Global ecosystem service and biodiversity impact maps
We developed high resolution (0.0028 degrees, ~300 meters) global maps for quantifying assets’ impacts on 8 measures of ecosystem services and biodiversity. We first modeled potential natural vegetation, or the vegetation that might exist absent development in a given location, as the baseline condition. We followed the approach used by Damania et al.14, applying to all land areas including current urban areas.
We then modeled the 8 measures of ecosystem services and biodiversity under these baseline conditions. We selected four ecosystem services for which global modeling was possible and which capture a range of values of nature that are produced and delivered through unique phenomena (e.g., hydrologic flows, coastal storms, human travel) such that they are not spatially redundant with each other, and which are not commonly captured by existing ESG approaches. These ecosystem services, sediment retention, nitrogen retention, coastal risk reduction, and nature access were modeled with the same methods as described in Chaplin-Kramer et al.15, using extensions of the InVEST16 suite of models. For nitrogen retention, we modeled loading rates based on the current land use/land cover44, representing fertilizer application in agricultural areas and background loading rates for all other landcover types. Combing nitrogen loading from a current scenario with retention provided by a baseline scenario of potential natural vegetation allows us to estimate the nitrogen retention service that would be provided by returning a location to natural vegetation while keeping the rest of the landscape under current conditions. Again following Chaplin-Kramer et al.15, for all ecosystem services biophysical measures were combined with measures of the number of people benefitting to yield a relative measure of realized ecosystem service value: number of people downstream benefiting from clean water from nutrient and sediment retention, number of people within the protective distance of coastal habitats for coastal risk, and number of people within 1 hour travel of natural and semi-natural lands for nature access.
We include four indicators of biodiversity, each capturing a different dimension. Species richness is the number of different vertebrate species (amphibians, birds, mammals, and reptiles) represented in an area. Red List species is a measure of the number of threatened, endangered, and critically endangered vertebrate species potentially present at a location according to the IUCN Red List of Species45. Endemic species are represented by a range-weighted species richness map, which weights rare species more heavily than common species. This is done by weighting each species by the inverse of its range size. Key Biodiversity Areas (KBAs) are areas that contribute significantly to the global persistence of biodiversity, identified according to a set of globally agreed-upon criteria46. Global maps of species richness, Red List species, and endemic species were modeled under baseline conditions (potential natural vegetation) following the methods in Damania et al. 202314. We created a global map with binary values, indicating where locations were within 1 km of a KBA47. This was intended to account for the fact that development activities can impact sensitive biodiversity and ecological functions beyond a project’s footprint, primarily within 1 km of distance48,49.
To identify hotspots and their areas of overlap, we calculated the 90th percentile of values for each ecosystem service or biodiversity metric. Oceans and areas with no data were excluded from the percentile calculations. Areas with positive values for coastal risk reduction and areas within 1 km of a KBA made up less than 10 percent of land area, so all non-zero values for these metrics are included in the hotspots.