There are hundreds of thousands of flights per day. Adding an additional flight, or even an additional thousand flights, to substantially improve Google doesn't seem like a big cost. Consider: Would your life be worse if one random trans-American flight was cancelled today, or if Google searches became 10% worse?
Another way of thinking about this same point, is, why is the author writing about language models if they are so concerned about the environment. Surely the airline industry is a better subject as, again, they fly hundreds of thousands of flights each day. It's hard to take someone seriously when they are focusing on an infinitesimal part of a huge problem.
It's also misleading because there is a difference between energy used by an airline flight, where the energy comes from burning jet fuel, and energy used in a data center. In Google's case (the people training BERT) the energy used was 100% renewable - Google reached that goal in 2017. Perhaps Open AI didn't use renewable energy to train GPT-3, but I wager they didn't power their machines by burning jet fuel either.
Maybe electricity used to power to train language models will become a meaningful issue at some point in the future. I don't think that future is close at hand though.