Sorry, I have to resist the urge to throw up when I read that anything written by Hawkins is "state of the art" since he is the author of:
Hawkins, T. R., Singh, B., Majeau-Bettez, G. and Strømman, A. H. (2013), Comparative Environmental Life Cycle Assessment of Conventional and Electric Vehicles. Journal of Industrial Ecology, 17: 53–64. doi: 10.1111/j.1530-9290.2012.00532.x
That paper can be best described as a hit piece with such huge errors that either he is incompetent or he's an industry shill. He did publish a corrigendum that corrected the most egregious error, but that doesn't even come close to fixing all the problems.
(2013), Corrigendum to: Hawkins, T. R., B. Singh, G. Majeau-Bettez, and A. H. Strømman. 2012. Comparative environmental life cycle assessment of conventional and electric vehicles. Journal of Industrial Ecology DOI: 10.1111/j.1530-9290.2012.00532.x. Journal of Industrial Ecology, 17: 158–160. doi: 10.1111/jiec.12011
His paper was used by a slew of anti-EV advocates to attack the electric vehicle movement and Tesla in particular.
Note these parts from his paper:
"Although this study incorporates the cradle-to-gate portion of the battery inventories by Majeau-Bettez and colleagues (2011)..."
"The cradle-to-gate battery production impacts estimated by Majeau-Bettez and colleagues (2011) (22 kg CO2-eq/kg) are substantially higher than the estimates by Notter and colleagues (2010) (6 kg CO2-eq/kg) or Samaras and Meisterling (2008) (9.6 kg CO2-eq/kg). These differences, which mostly stem from differing assumptions concerning manufacturing energy requirements and system boundaries, are indicative of the need for better public primary inventory data from the battery industry. "
So, yes, of course Hawkins used the "substantially higher" Majeau-Bettez battery production estimates and ignores the others. He didn't even use the average of the 3 which would be almost half of his estimate.
At first glance, the chart that Fallenone posted from his meta-analysis paper does seem more in-line with reality, but since his meta-anaylsis includes his own and Majeau-Bettez research, it's still wrong. Very wrong. And he certainly didn't bother to correct the misconceptions of people that used his research to apply to Tesla. If he was truly competent, he would quickly draw the distinctions between his analysis and the very different Tesla/Panasonic production. He didn't and allowed a slew of hit pieces to misapply his research in in a very public way.