This edited extract is from the breakfast chapter of Sarah Bridle’s Food and Climate Change Without the Hot Air.
Check out the article in The Times here.
Tea and Coffee
As you drop the teabag into your cup, think about its journey from tea plants far away. The good news is that transporting a teaspoon (2 grams) of tea half way across the world by boat causes very little greenhouse-gas emissions compared to most other things you’re likely to eat today.
What about boiling the water? Burning natural gas to heat a pan, or using electricity generated from burning coal or natural gas, unlocks carbon dioxide taken up by plants millions of years ago, and releases it back into the atmosphere, which causes global warming.
30 gCO2e of greenhouse-gas emissions are caused by making one cup of black tea assuming that, like many people, you boil twice as much water as you really need.
Boiling the water causes more emissions than the teabag itself, but even so the total is still small compared to our reference value of 3 kg per day per person.
1 g teabag = 3 g emissions
Do you prefer coffee? Coffee is made from the seeds of the coffea plant, which are often referred to as “beans”. To grow well, the coffea plants are tended, watered and fertilized. For dried coffee, the emissions from the fertilizer cause about one third of the total emissions; processing the bean from plant to cup and packaging contribute most of the remainder.
1 g instant coffee powder = 17 g emissions
For a typical cup of coffee, the instant coffee emissions are similar to those from boiling the water. Even so, the amount of emissions from a single cup, are small compared to our reference value of 3 kg per day per person.
Most people in the UK drink their tea with milk, typically adding just over one tablespoon (20 ml) to each cup.
How do cows contribute to climate change? Tabloid newspaper headlines warn about methane from cow farts, but in fact most methane comes out of their mouths as burps.
A typical dairy cow eats over 70,000 kCal a day, churning out milk at an average rate of 16 litres a day, but at the same time it’s burping out over 7 kilos of emissions each day.
We can already estimate the emissions from milk by sharing out the 7 kilos of emissions across the 16 litres of milk produced. A more accurate calculation takes into account the methane burped by the cow during the two years before it reached milk-bearing age.
In addition to the cow burps, we have to add in the impact from cow poo. Depending on how it’s stored and distributed on the fields as fertilizer, cow manure produces both methane and nitrous oxide and adds about 50% to the total milk emissions.
1 g milk = 2 g emissions
Overall, cows’ milk causes about twice its own weight in greenhouse-gas emissions, but this number can vary by more than 50% depending on how the cows are raised. For example, if the cows produce less milk each day then the emissions will be higher.
Keen to learn more? Food and Climate Change Without the Hot Air covers popular breakfast, lunch, snack and dinner options.