I didn't assess the study itself, but it focuses on the wrong metric. Even if a single coffee pod were to be more CO2-efficient than an espresso from an espress

I didn't assess the study itself, but it focuses on the wrong metric. Even if a single coffee pod were to be more CO2-efficient than an espresso from an espresso machine, the popularity and consumerist approach makes it so that you will have more coffee (rebound effect). Without a nespresso machine in the office or at home, would you walk out to the coffee shop for a coffee 3 times a day? Coffee is made from an exotic plant and should be treated as a special treat, not a "brain enhancing" commodity like it is today. If people had this mindset, it wouldn't matter how you brew your coffee.