COFFEE’S daily ritual hides a surprisingly complex climate story: every fragrant cup is the end point of a globe-spanning chain of emissions that starts in tropical hillsides and ends in your kitchen or the cafe down the street.
To answer, “how much carbon is emitted in the process of coffee growing, cultivation and brewing and its wastage?” We have to walk the entire life cycle, because the footprint is the sum of many small (and a few very large) pieces.
The short version: a plain black coffee typically ranges from a few dozen grams of CO₂-equivalent (CO₂e) per cup to a few hundred, depending on how it’s brewed and how electricity is generated; add dairy and the number jumps.
Per kilogram of green coffee (unroasted), credible life-cycle assessments place farming-to-export emissions most often around 10–13 kg CO₂e, though results vary by location and method.
What follows is a grounded tour through the biggest contributors and what can be done about each.
On the farm, carbon flows are driven by fertilisers, land management, yields and whether forests were cleared to plant coffee.
Synthetic nitrogen fertiliser and on-farm energy use emit nitrous oxide and CO₂; processing cherries into parchment can add more if it’s energy-intensive or wastewater is poorly handled.
A widely cited synthesis finds conventional production in major origins like Brazil and Vietnam in the 11–13 kg CO₂e per kg of green coffee range, while broader systematic reviews report much wider spans (roughly 2–23 kg CO₂e/kg green), reflecting differences in agronomy, productivity and accounting boundaries.
Higher yields reduce per-kilogram emissions, while shade-grown systems can store more carbon in trees but may lower yield if poorly managed.
The headline: farm-stage emissions are material and variable, and they set the baseline before a single bean is roasted.
After harvest, coffee is pulped, washed or dry-processed, dried and milled.
Energy for mechanical drying and electricity for milling add ounces, not pounds, of CO₂e compared to farming.
And international shipping (ocean freight) is generally a small slice of the total per cup.
That said, when processing relies on diesel or grid power with high emission factors, or when beans are air-freighted (rare for coffee), these stages can swell.
Most cradle-to-export assessments still leave the farm stage as the dominant pre-consumer contributor.
Roasting requires heat; packaging protects quality. Gas-fired roasters are common; electric roasters’ footprints depend on the grid.
This tends to be a modest contributor per cup but can be noticeable per kilogramme roasted, especially for small batches.
Packaging is frequently scrutinised for sustainability, yet in life cycle assessment (LCA) terms it’s usually a minor share compared to brewing energy and milk in the consumption stage.
Surprisingly, a large share of a cup’s footprint often occurs at the moment you make it, because heating water consumes energy.
Analyses aimed at consumers have estimated that roughly a third of a cup’s emissions can happen during the consumption stage, mostly from boiling water especially if you heat more than you need or use an inefficient appliance.
Crucially, your local electricity mix and appliance efficiency can swing results dramatically.
Brewing methods also matter: in experiments modeling 40 mL servings, moka pots and capsule machines showed different footprints per shot due to device energy use and waste handling, with values on the order of single-digit to tens of grams of CO₂e for a small espresso-sized cup.
Scale that up to the more common 200–350 mL mug and results naturally rise.
What’s “A Cup” Worth in Carbon? Ranges You Can Use
A WWF-supported analysis placed brewed coffee at about 0.25 kg CO₂e per liter (so ~50 g CO₂e for a 200 mL cup) when including brewing energy; instant coffee was lower at ~0.16 kg CO₂e/L because it uses less coffee per serving.
Other consumer-facing syntheses put a 12-ounce (355 mL) black coffee closer to ~0.26 kg CO₂e, reflecting both the larger volume and differing electricity assumptions.
Espresso-focused LCAs modeling 40 mL shots show values from roughly 8–18.5 g CO₂e per serving depending on method again, small volumes, so small numbers.
The spread tells you two things: your grid and your brewing habits are powerful drivers; and dose size (grams of coffee per cup) is a quiet but major variable.
Milk: The Carbon Multiplier in Lattes and Cappuccinos
When you add dairy, the footprint often jumps more than all the other stages combined.
One synthesis estimated ~0.33 kg CO₂e for a latte vs ~0.06 kg for an espresso, driven by milk’s high emissions per liter.
Different milk styles (skim vs whole), foam volumes and cup size shift the exact number, but the pattern holds: milk is the multiplier.
Waste: Grounds, Methane and Why Your Bin Choice Matters
Coffee’s carbon story doesn’t end when you tip the puck from your portafilter.
Spent grounds and other by-products can create greenhouse gases if sent to landfill, where they can emit methane, a gas far more potent than CO₂ over a 100-year period.
Composting or anaerobic digestion captures nutrients (and in the latter case, energy) and avoids landfill methane.
There’s also a flourishing wave of upcycling: researchers have converted used grounds into biochar for concrete, replacing sand, boosting strength and potentially lowering cement demand a major emissions source while keeping organics out of landfill.
The takeaway: divert grounds from landfill whenever possible; if your city offers organics collection or community compost, use it.
Putting It Together: From Kilogrammes per Kilo to Grams per Cup
If you prefer rules of thumb, start from the farm: roughly 10–13 kg CO₂e per kg of green coffee is a common ballpark in high-yield conventional systems, with wide variation (about 2–23 kg CO₂e/kg) across studies.
Translate that into cups: a 200 mL mug might use ~12 g of roasted coffee (about ~10 g green equivalent, ignoring roast loss for simplicity).
At 11 kg CO₂e/kg green, the farm-to-export share per mug would be on the order of ~110 g CO₂e before roasting, packaging and brewing.
Add roasting and packaging (often modest), then brewing energy (perhaps ~20–100+ g depending on your electricity), and a typical black mug can plausibly land anywhere from ~50 g to a few hundred grams of CO₂e.
That’s a wide band, but it reflects real-world diversity in dose size, appliances and grids. Add 150–250 mL of dairy milk and the total can easily triple.
Use these as directional estimates, not absolutes; what matters are the levers you control.
How Your Choices Shift the Numbers (A Practical Playbook)
Brew efficiently
Heat only the water you will use; avoid “keep warm” plates; descale to keep heaters efficient.
For espresso or small cups, devices with quick heat-up and low standby losses help; for drip, an efficient kettle plus manual brewers can shine.
These changes directly cut the consumption-stage share found in consumer LCAs.
Mind the dose
More coffee per cup means more upstream emissions. If you like stronger coffee, consider smaller volumes rather than larger doses or try instant for days when you want the least-emissions option per litre.
Tweak the milk
Go small on milk, choose foamy styles that use less liquid, or try lower-carbon alternatives you enjoy. Even modest reductions often beat the gains from swapping cups or filters.
Handle grounds wisely
Keep them out of landfill; home compost (in small amounts), municipal organics bins, or community gardens are all better.
If your area pilots biochar or industrial composting participate, you’re cutting methane and sometimes displacing fossil fuels or cement.
Buy from efficient supply chains
Higher-yield farms with good nitrogen management and improved processing can deliver lower footprints per kg of beans.
Certifications and transparent roasters who publish LCA-informed data can help you choose.
Caution, Context and Comparisons
A few cautions help interpret any coffee carbon number you see. First, system boundaries matter: “cradle-to-farm gate”
excludes roasting and brewing; “cradle-to-cup” includes everything; some studies exclude milk by default and list it separately.
Second, electricity assumptions swing results: a 1 kWh kettle powered by coal-heavy grids has several times the emissions of the same kettle on renewables.
Third, serving size and dose dominate per-cup math espresso studies reporting 8–18.5 g CO₂e for a 40 mL shot cannot be compared directly to a 12-ounce mug.
Finally, LCAs often present ranges, not single truth points; a 2024 methodological review explains why results can vary widely depending on scope, data quality and treatment of land-use change.
That variability is frustrating for those seeking a single answer but empowering if you’re trying to reduce your own impact, because it highlights practical levers at home and in cafes.
The views expressed here are those of the writer and do not necessarily represent the views of Sarawak Tribune. The writer can be reached at khanwaseem@upm.edu.my.
