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.