According to BBC News' "Climate change food calculator," a cup of tea every day adds around 33 pounds to an individual's annual greenhouse gas emissions with coffee coming in at about 10 times.
You have to think about how you consume the drink and how it got to you.
One large factor of the carbon footprint of your coffee vs tea isn't actually the coffee or the tea — it's the milk. If you're adding cow milk to either drink, that increases the carbon footprint since cows produce methane.
Matcha is Moderately Sustainable
Carbon footprint: likely low, 1.9 kg CO2e to produce 1 kilogram or 2.2 pounds of tea, a car driving equivalent of 4.5 miles or 7.25 kilometers
Destruction: low, matcha production is relatively sustainable, there is no known significant damage to air, water, land, soil, forests, etc. as long as pesticides have not been used, be sure to buy Non-GMO/organic, as toxic, chemical pesticides contaminate air, water, soil, etc., a typical tea plant used to produce matcha can live for a half-century or longer, making it one of the most sustainable and environmental food crops in existence, matcha is the only kind of tea that uses the entire leaf which creates less waste.
