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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:

RatingMeaningCompared to Average
★★★Climate-friendly50% better or more
★★☆Better than average0-50% better
★☆☆Worse than average0-100% worse
☆☆☆Very high impact300%+ 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:

  1. Agricultural production

    • Farm emissions (fertilizers, machinery, livestock)
    • Land use changes
    • Methane from animals

  2. Transportation

    • Distance from origin to market
    • Transport mode (ship, truck, air)

  3. Processing

    • Manufacturing energy
    • Refrigeration
    • Heating/cooking in production

  4. 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:

GasGlobal Warming PotentialExample Source
CO₂1×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​

  1. Look at the stars first — Choose ★★★ and ★★☆ foods when possible

  2. Compare within categories — If choosing protein, compare:

    • Legumes (low CO₂) vs. chicken (moderate) vs. beef (high)

  3. Consider frequency — High-impact foods occasionally have less total impact than moderate-impact foods eaten daily

  4. 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:

Contact Eaternity →