Carbon Science

Understanding the science behind carbon emissions and how your daily activities impact the climate

🌡️ What is a Carbon Footprint?

A carbon footprint is the total amount of greenhouse gases (primarily CO₂) generated by your actions. It's measured in kilograms or tons of carbon dioxide equivalent (CO₂e).

🌍

Global Average

4 tons/year

Per person worldwide

🇺🇸

US Average

16 tons/year

Per person in the USA

🎯

Target Goal

2 tons/year

By 2050 to limit warming

📊 Emission Factors by Category

🚗 Transport Emissions

✈️ Airplane (short-haul)0.25 kg CO₂/km

Most emissions-intensive per km. A 500km flight = 125 kg CO₂

🚗 Gasoline Car (average)0.21 kg CO₂/km

Average car. 10km commute = 2.1 kg CO₂ per day

🚕 Taxi / Ride-hail0.18 kg CO₂/km

Slightly more efficient due to newer vehicle fleets

🚌 Bus0.06 kg CO₂/km

70% less than car. Great for daily commutes

🚆 Train / Metro0.04 kg CO₂/km

80% less than car. Best public transport option

🚴 Bicycle / Walking / E-Scooter0.00 kg CO₂/km

Zero emissions! Best for trips under 5km

🍽️ Food Emissions

🥩 Beef10.0 kg CO₂/serving

Highest emissions. Includes methane from cattle, land use, and feed production

🐑 Lamb7.5 kg CO₂/serving

Second-highest due to methane emissions

🧀 Cheese3.5 kg CO₂/serving

Dairy production requires significant resources

🐷 Pork3.0 kg CO₂/serving

Moderate emissions from feed and land use

🐔 Chicken / Poultry1.5 kg CO₂/serving

More efficient than red meat. 85% less than beef

🐟 Fish1.2 kg CO₂/serving

Varies by fishing method. Farmed fish may differ

🥗 Vegetarian0.5 kg CO₂/serving

95% less than beef. Plant-based diet is most sustainable

🌱 Vegan0.3 kg CO₂/serving

Lowest emissions. No animal products

⚡ Energy Emissions

💡 Electricity (grid average)0.50 kg CO₂/kWh

Varies by region. Coal = higher, renewables = lower

🔥 Natural Gas5.30 kg CO₂/therm

Common for heating and cooking

🛢️ Heating Oil10.2 kg CO₂/gallon

Higher emissions. Consider heat pumps

☀️ Solar / Wind0.00 kg CO₂/kWh

Renewable energy = zero operational emissions

🛍️ Shopping Emissions

👕 Clothing (new)5-15 kg CO₂/item

Fast fashion has high carbon cost. Buy secondhand when possible

📱 Electronics (phone)80 kg CO₂

Manufacturing and mining materials. Keep devices longer

💻 Laptop200 kg CO₂

Complex manufacturing. Repair instead of replace

♻️ Secondhand Items~0 kg CO₂

Reusing extends product life and avoids new manufacturing

🧮 How We Calculate Emissions

Our Methodology

CarbonCoach uses emission factors from trusted scientific sources:

  • IPCC (Intergovernmental Panel on Climate Change) - Global standards
  • EPA (Environmental Protection Agency) - US-specific data
  • DEFRA (UK Department for Environment) - Transport and energy factors
  • Our World in Data - Food emissions research
  • Life Cycle Assessment (LCA) studies - Product manufacturing

Calculation Formula

Emissions (kg CO₂) = Activity Value × Emission Factor

Example:
Car Trip: 15 km × 0.21 kg CO₂/km = 3.15 kg CO₂
Beef Meal: 1 serving × 10 kg CO₂/serving = 10 kg CO₂

Accuracy & Limitations

Our calculations are estimates with approximately ±15% accuracy. Actual emissions vary based on:

  • Vehicle age, fuel efficiency, and driving conditions
  • Food production methods (organic, local, seasonal)
  • Regional energy grid mix (coal vs. renewables)
  • Product manufacturing location and methods

Despite these variations, our factors provide reliable relative comparisonsto help you make better choices.

🌡️ Why It Matters

The Climate Crisis

  • • Global temperatures have risen 1.1°C since pre-industrial times
  • • We need to limit warming to 1.5°C to avoid catastrophic impacts
  • • Individual actions collectively make a massive difference
  • • Every ton of CO₂ reduced helps slow climate change

Your Impact

  • • Switching to plant-based diet: -1.5 tons CO₂/year
  • • Using public transport: -2.0 tons CO₂/year
  • • Switching to renewable energy: -2.5 tons CO₂/year
  • Combined: Reduce footprint by 35-40%

Ready to Track Your Carbon Footprint?

Use science-backed data to understand and reduce your environmental impact.

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