How to Read the Poster
This guide explains how to interpret all the information displayed on the CO₂ Food Poster.
Poster Legend
CO₂ Values
Each food item shows its CO₂ value in grams of CO₂ equivalents for the amount that covers ⅓ of your daily nutritional requirements.
Example:
- Covering ⅓ of daily requirements with vegetables: ~620g CO₂
- Covering ⅓ of daily requirements with lobster: ~14,000g CO₂
This means choosing vegetables over lobster for one-third of your daily nutrition saves approximately 13,380g of CO₂ — equivalent to driving about 80 km in an average car.
Star Ratings
Foods are rated with 0-3 stars based on their climate impact:
| Rating | Meaning | Compared to Average |
|---|---|---|
| ★★★ | Climate-friendly | 50% better or more |
| ★★☆ | Better than average | 0-50% better |
| ★☆☆ | Worse than average | 0-100% worse |
| ☆☆☆ | Very high impact | 300%+ worse |
The goal: Choose more ★★★ and ★★☆ foods to reduce your dietary carbon footprint.
Portion Information
Each food shows a portion number indicating how much of your daily nutritional needs 100g of that food fulfills.
Higher number = more nutritionally dense
For example:
- Nuts might show a high portion number (calorie and fat dense)
- Lettuce shows a low portion number (mostly water)
This enables fair comparison: you don't need to eat the same weight of different foods to get the same nutrition.
Reading the Layout
Food Groups
Foods are organized in visual clusters based on their category:
- Vegetables — Generally low CO₂ impact
- Fruits — Low to moderate impact
- Grains & Legumes — Low impact, high protein efficiency
- Dairy — Moderate impact
- Meat — Moderate to high impact
- Seafood — Variable, some very high
Color Coding
The visual design uses color to indicate climate impact:
- Green tones — Climate-friendly choices
- Yellow/Orange tones — Moderate impact
- Red tones — High impact choices
Understanding the Science
What's Included in CO₂ Values
The CO₂ equivalent values account for:
-
Agricultural production
- Farm emissions (fertilizers, machinery, livestock)
- Land use changes
- Methane from animals
-
Transportation
- Distance from origin to market
- Transport mode (ship, truck, air)
-
Processing
- Manufacturing energy
- Refrigeration
- Heating/cooking in production
-
Packaging
- Material production
- Disposal or recycling
What's NOT Included
The values do not include:
- Consumer preparation (home cooking)
- Food waste at consumer level
- Retail storage
CO₂ Equivalents Explained
The term "CO₂ equivalents" (CO₂e or CO₂-eq) means all greenhouse gases are converted to their equivalent impact in CO₂:
| Gas | Global Warming Potential | Example Source |
|---|---|---|
| CO₂ | 1× | Energy, transport |
| Methane (CH₄) | 28× | Cattle, rice paddies |
| Nitrous oxide (N₂O) | 265× | Fertilizers |
This allows comparison of total climate impact, not just CO₂.
Practical Tips
Making Climate-Friendly Choices
-
Look at the stars first — Choose ★★★ and ★★☆ foods when possible
-
Compare within categories — If choosing protein, compare:
- Legumes (low CO₂) vs. chicken (moderate) vs. beef (high)
-
Consider frequency — High-impact foods occasionally have less total impact than moderate-impact foods eaten daily
-
Check origins — Some foods on the poster note that transport method (air vs. ship) significantly affects impact
Common Surprises
Foods that are better than expected:
- Seasonal local vegetables
- Legumes and beans
- Grains
- Many fruits
Foods that are worse than expected:
- Butter (high dairy input)
- Cheese (concentrated dairy)
- Air-freighted produce
- Greenhouse-grown off-season vegetables
Example Calculations
Daily Food Unit (DFU) Calculation
For 100g of whole-grain cereals containing:
- 10g proteins
- 7g fats
- 1434 kJ energy
- 16g water
- 84g dry weight
The DFU is calculated as:
(10/50 + 7/66 + (1434 - 17×10 - 37×7)/6000 + 16/2500 + 84/600) / 5 = 0.124
With a CO₂ value of 85g CO₂/100g, the final score is:
685g CO₂/DFU → 91.2% better than average
This means whole-grain cereals score better than 91.2% of all products in terms of climate efficiency per unit of nutrition.
Using the Poster Effectively
For Individuals
- Pin it on your refrigerator as a daily reference
- Use it when meal planning
- Share insights with family and friends
For Educators
- Discuss the methodology in science classes
- Compare regional food choices
- Calculate meal carbon footprints as exercises
For Food Service
- Reference when creating menus
- Identify high-impact ingredients to reduce or replace
- Communicate choices to guests
Questions?
For questions about the methodology or data: