I wish they'd stop this crap and let the guys race.
Motorsport by it's very nature, can never be green.
While it is okay to be efficient, it should never trump the racing.
You've saved fuel by cutting half the cylinders.
Now concentrate on a race schedule which host the races in succession, so you're not running jumbos all over the planet and back.
Let that be your concession to being 'greener'.