Regular banking transactions also consume electricity, and they likely require way more than bitcoin does. Banks have to have employees, servers, lots of things that require electricity. Employees need to drive to work. Employees and Servers need air conditioning. There's tons of opportunity costs there as well. If it takes electricity only to verify transactions through bitcoin, the entire process can be done with clean energy as well, you can't say the same with banking. Banks require employees, and each human being has a carbon emission cost. Bitcoin may use lots of energy, but so does regular banking transactions. It's kind of backwards to bitch about bitcoin and how much energy it costs if you don't also compare it to how much power banking already costs.
Definitely true, there's really no process on earth that doesn't leave some sort of imprint. I think the cost of mining atleast in Bitcoin's case is worth the extra levels of security and decentralization that it brings... and where that energy comes from is still possible with renewable resources.