Latte is usually my drink of choice when I walk into a coffee shop. As luck would have it, I've been invited to discuss all that is involved in producing a cup of latte at the Lewis and Clark Environmental Affairs Symposium. This compels me to find out what goes into a tall (12 oz) cup of latte and what GHG emissions come out. Surprising result: The coffee itself appears to play a relatively minor role in the carbon footprint.
The coffee is typically grown in a country like Brazil (which happens to be the largest coffee producer). Primary processing produces green beans from the coffee fruit -- this can be very water-intensive if wet processing is used. The green beans are then shipped to consumer countries where they are roasted and ground. The latte itself is just milk and espresso coffee in the right proportion.
CarbonScopeData provides all the production data for coffee and milk, and the newly updated FoodCarbonScope provides a quick LCA-quality analysis. It turns out that a typical tall latte served in a US coffee shop, made with 2% milk, has a carbon footprint of about 0.46 Kg CO2e, including the disposable cup and all transportation.
Here is a breakdown of the results. Production (meaning agricultural production and processing) dominates the emissions. More than half of the total emissions come directly from the milk; the emissions from coffee are just 10% of the total. The next biggest contributor is labeled "cooking" (meaning coffee making in this case), which includes the disposable cup and the electricity/water used to make the coffee drink and accounts for about a quarter of the total emissions. Distribution within the US accounts for the rest of the footprint.
Another interesting finding: The 12 oz cup of latte has a huge water footprint of about 108 liters, most of it due to the milk. (A liter of 2% milk requires about 390 liters of water to produce.) Although coffee does use a lot of water as well for growing and processing, milk is the dominant component in a latte.
How do you get a sustainable cup of latte? For starters, you need sustainably produced milk in order to have sustainable latte.