This is an interesting calculation to do but the specific example needs improvement. First, the calculation of the available supply is based on known, existing

This is an interesting calculation to do but the specific example needs improvement. First, the calculation of the available supply is based on known, existing reserves economically retrievable at current prices. Changes in demand will change both the known reserve quantity and the price. Lithium is currently about $1/kg, so there is plenty of room to grow price to increase supply without affecting the cost of batteries. So a reasonable estimate of lithium supply has to include both demand volume and price. Reserve growth based on demand volume and price is a very tricky thing to forecast. Second, the choice of 3.4 billion vehicles to "bring the entire world to North American levels" as a goal is an unrealistic number for many reasons. Regional economics, geography, and social density vary quite radically around the world. The built infrastructure varies and supports many different transportation modalities. It also doesn't take in to account changes in technology, infrastructure, and social organisation during such a radical transition. So a more reasonable estimate would be to simply replace all vehicles on the road with BEVs. Last, the note could also be improved by doing sanity checks. For instance, could the world production capacity of any other energy storage mechanism, including oil, hydrogen, ethanol, etc. support 3.4 billion vehicles? It's always useful to compare what you are calculating to the alternatives. There are currently about 1 billion cars in use in the world. Using just the reserve numbers quoted in the article it seems economically feasible to replace them all with Lithium chemistry battery electric vehicles.