When you join CarbonStory, you are initially given the average carbon footprint for someone living in your country of residence. If you are happy with this footprint calculation, you can proceed straight away to building your portfolio of offset projects. Alternatively, you have the option of going to the calculator and completing a high-level calibration of your carbon footprint followed, if you wish, by detailed calculations for various categories including housing, food, transportation and everything else. We recommend that you take the time to calculate a detailed carbon footprint as it will give you a better idea of actions you can take to reduce your greenhouse gas emissions.
Our calculator is global with data from 147 countries covering the vast majority of the world’s population.
Our calculator is based on peer-reviewed science published in the International Journal of Greenhouse Gas Reviews by CarbonStory's co-founder Andreas Birnik. This research article outlined 13 evidence-based principles for how individual/household carbon footprints should ideally be determined. The article also evaluated the 15 most popular carbon footprint calculators on the web and identified significant shortcomings of most of the calculators. To access the research article, please click here. Otherwise, we provide a summary of the calculation principles below:
Principle 1 – Greenhouse Gases
"A personal carbon footprint calculator should as a minimum requirement estimate emissions relating to carbon dioxide, methane and nitrous oxide."
Carbon dioxide, methane and nitrous oxide account for 98.9% of overall greenhouse gas emissions so a footprint accounting for these three gases can be considered comprehensive. Focusing on only carbon dioxide would result in an underestimated footprint as carbon dioxide only represents 77% of overall greenhouse gas emissions.
Principle 2 – Global Warming Potential
"A personal carbon footprint calculator should base conversions to carbon dioxide equivalents on 100-year GWP conversion factors."
The emerging standard is to consistently use 100-year global warming potential (GWP) figures when converting greenhouse gases to carbon dioxide equivalents.
Principle 3 – Consumption Data
"A personal carbon footprint calculator should estimate consumption based footprints as the purpose is to determine an individual’s climate impact regardless of where goods and services consumed are produced."
Footprint impact should be based on the final consumption of products and services. This also includes accounting for international aviation and shipping. This approach encourages sustainable consumption by providing transparency to end-users about the climate impact of their lifestyle choices regardless of where products and services used are produced.
Principle 4 – Income / Consumption Adjustment
"A personal carbon footprint calculator should allow users to adjust for income or consumption level instead of only using national averages."
A carbon footprint calculator should adjust for income/consumption given that the scientific literature has consistently shown a clear relationship between these variables and a person's greenhouse gas footprint. Wealthier individuals tend to live in larger homes, use more energy, fly more and drive more.
Principle 5 – Income / Consumption Adjustment
"A personal carbon footprint calculator should adjust the relative distribution of consumption categories as a function of the income level."
As income increases, there is a shift in the relative composition of consumption categories away from necessities (e.g. food) towards discretionary spending (e.g. cars and flights).
Principle 6 – Household Size
"A personal carbon footprint calculator should adjust for the number of people living in a household."
Research has shown that the per capita footprint is reduced in larger households given that people share housing, furnishings, appliances as well as heating and cooling loads.
Principle 7 – Housing Emissions
"A personal carbon footprint calculator should allow users to model their housing emissions in detail."
Given that housing is one of the major emission categories, users should be given the option to model their housing emissions in detail.
Principle 8 – Housing Emissions
"A personal carbon footprint calculator should capture emissions from household energy use as well as emissions from furnishings, appliances, building material and maintenance of buildings."
A carbon footprint calculator should capture both energy and non-energy housing related greenhouse gas emissions. The non-energy emissions relate to building material, construction, maintenance, appliances, furniture and textiles used in the home.
Principle 9 – Food Emissions
"A personal carbon footprint calculator should allow users to model their food related emissions in detail."
A carbon footprint calculator should enable users to reflect differences in consumer choices in terms of diet and shopping behavior. For dietary choices, this typically falls on a continuum from a strictly vegan diet towards a meat heavy diet. For shopping choices, a key driver is the extent to which food is organically grown and sourced locally.
Principle 10 – Transportation Emissions
"A personal carbon footprint calculator should allow users to model their transportation related emissions in detail."
A carbon footprint calculator should allow users to compute their transportation emissions in detail covering different road, rail and air travel modes. The calculator should reflect differences in energy efficiency of road transport in order to encourage users to switch towards more fuel-efficient and less emission intensive vehicles. Flight calculations should distinguish between short- and long-haul flights.
Principle 11 – Transportation Emissions
"A personal carbon footprint calculator should allow users to include radiative forcing of flights when modeling flights emissions."
While the scientific debate is not fully settled regarding the radiative forcing effect of flight emissions, users should be given the chance to include radiative forcing in line with the precautionary principle.
Principle 12 – Comprehensive Footprints
"A personal carbon footprint calculator should provide a comprehensive footprint including allocating emissions for a variety of consumption categories."
A carbon footprint calculator should cover all major emission categories rather than just a few. While classification schemes differ, this typically includes categories such as housing, food, transportation, restaurants and hotels, recreation and culture, clothing and footwear, communications, alcohol, health, education and other (roads, airports, emergency services, emergency services, etc.). The purpose is to give an accurate estimation of an individual's direct and indirect climate impact across all key consumption categories.
Principle 13 – Emission Factors
"A personal carbon footprint calculator should base calculations on up-to-date and country/region specific emission factors whenever possible."
The calculator should use recent emission factors that are appropriate for the user's country and state if relevant.