The authors note that metal production accounts for 11% of global energy use and a significant portion of the annual carbon footprint. Further, they note that the mining of metals required for the transition to green energy is moving to areas of high biodiversity.
The authors contend that continuing to produce from land-based sources, in effect, shift the environmental and social burden from fossil fuels to metals.
According to the paper, the replacement of the internal combustion engine with an EV battery almost triples the CO2e emissions from vehicle manufacturing, thereby reversing gains from reducing vehicle emissions. This, say the authors, raises questions about the future source of metals for EV batteries.
Recycling metal stocks which are already in use is the most responsible solution in the long term, but the authors state it will take decades to build up the primary stock of metals that will make mass-scale EV metal recycling possible.
The paper compares land ores with seafloor polymetallic nodules and considers the transitional demand for the four base metals used in EV battery cathodes and wiring: nickel, cobalt, manganese and copper.
The paper compares the impacts of producing metals for one billion EVs across climate change, non-living resources, biodiversity, and social and economic impacts.
The authors conclude that climate change impacts would be significantly reduced by producing metals from polymetallic nodules; specifically that the GWP (Global Warming Potential) of producing metals from land ores is higher than for seabed minerals; that land-based mining carbon sequestration impacts are higher than those for seabed minerals, and that impacts on non-living resources (such as land use and pollution) would be greater with land-ore mining.
The results, say the authors, are based on a specific set of assumptions that can and should be challenged and developed further.