Evaluating asset-level impacts: mining
This approach can also be used for more detailed evaluations of impacts
where assessments at the level of individual assets is desired and
feasible. As an example, we analyze individual lithium mining assets. We
integrated a dataset on the location of 23 global lithium mines with
high-resolution (~5m) satellite
imagery29 to map the footprint of individual mines. We
then combined these footprints with the global maps of ecosystem service
and biodiversity values to calculate mine impacts. These impacts account
for both mine location and the mine-specific area of land impacted.
Our results show that the magnitude of impact varies substantially among
mines (Figure 4). The range of potential impacts of lithium mining on
nature are determined by the location of Earth’s lithium reserves
relative to the location of ecosystem service and biodiversity hotspots,
but even given this constraint, there are options for acquiring lithium
with higher or lower costs to ecosystem services and biodiversity. This
asset-specific information can be weighed alongside information such as
differences in productivity and operation costs. Understanding the
impacts of specific assets or project footprints on natural capital can
help project developers, corporates, infrastructure investors, and other
decision makers limit their negative impacts and optimize for production
efficiency when evaluating investments in new or existing development.
Using high-resolution, asset-specific footprints also reveals the
impacts of many lithium mines to be much higher than estimated by
assuming a fixed, median size (Figure 4a). The fixed approach is
generally able to differentiate between high- and low-impact mines for
the ecosystem services of sediment retention and nitrogen retention but
was not as effective at distinguishing differences for biodiversity
(Figure 4b). Assuming a median area by asset type may be both necessary
and sufficient when comparing across many assets, such as when comparing
across thousands of companies. However, where feasible, asset-specific
footprints provide valuable additional information and spatial precision
in assessing impact, especially when comparing among assets within an
activity type or analyzing an asset over time. Of the 23 lithium mines
evaluated, the mine with the largest footprint (Chaerhan Lake, China at
>3,250 km2) is the most impactful mine on
endemic species, Red List species, and species richness, but other mines
had greater impacts on the other four measures. None impacted coastal
risk reduction. Five different mines represent the highest impact mines
across all seven metrics. Four of these five are in China, which
contains 8 of the 23 total lithium mines assessed.
Our approach can also leverage high resolution, high frequency satellite
imagery to assess how a mine’s footprint – and associated impact –
changes over time. Combining the mine footprint with high resolution
ecosystem service and biodiversity maps is important because these
impacts do not necessarily scale linearly with footprint area or
production. Using the Greenbushes, Australia lithium mine as an example,
with annual satellite imagery29 and production data
from 2016-202330, we find that the mine’s total
footprint increased around 75 percent, while annual production increased
around 140 percent (Figure 5, Table S2). Impacts to nitrogen retention,
sediment retention, and species richness each increased over 80 percent,
slightly more than would be expected by the change in footprint size
alone, indicating the mine expanded into higher impact areas over time.
In contrast, impacts to nature access, habitat for endemic species, and
habitat for threatened and endangered species increased slightly less
than the increase in footprint size. Across all ecosystem service and
biodiversity measures, the impact per tonne of lithium produced
decreased between 2016 and 2023, apart from a period of low production
around 2021 likely due to COVID-19. Given that demand for lithium is
increasing and will likely continue to in a transition to a lower carbon
economy23,24, intensity metrics can help show which
areas produce the most while limiting negative environmental impacts.
Capturing this level of granularity can help project developers and
investors explore the impact of an asset over time and analyze whether a
possible increase in negative impact due to a larger asset footprint is
justified by a meaningful increase in production. In addition to
evaluating past trends, the high-resolution ecosystem service and
biodiversity impact maps could also contribute to implementation of the
mitigation hierarchy at the asset level31, enabling
project developers to avoid and minimize impacts to the most sensitive
locations. The ability to compare impacts among mines can help guide
extraction towards more sustainable options for this important resource.