How does the One Small Step Carbon Footprint Calculator work?
Our carbon accounting system is a work in progress. While we’ve put a lot of work and thought into the current model, its accuracy is constrained by:
the information we can collect from you in order to predict your environmental impact; and
the reliance we have presently on self-reporting by users without access to real-world data on things like your energy usage, car usage or kgs of waste you create each week.
That said, we think the model we’ve built is promising and is only going to get better with time, especially as we look to partner with organisations where we can collate observed data. For example, with your consent, integrating your energy usage numbers through a partnership with your energy provider, or asking questions that help us figure out exactly how often you’re driving your car and it’s fuel efficiency.
We’ve outlined the methodology we’ve used below to calculate your quiz results in the One Small Step app, and the default assumptions we’ve used to figure out the environmental impact you can achieve by completing the current programs in the One Small Step app.
We are continuously improving this calculator, and we will update this page with changes to our model as we augment it.
Calculating your carbon footprint: methodology and assumptions
We combine the information you provide in your answers to the on-boarding quiz and Australian Bureau of Statistics (ABS) census reports on Australian income, expenditure, water & electricity usage to get a highly detailed breakdown of what your consumer habits are likely to be. These figures are influenced by what state you live in, how many people you live with, and what income bracket your household applies to.
We then run these energy, water, gas, fuel, food & spending figures through a consumption-based accounting model provided by Tomorrow co. to create an annual carbon dioxide equivalent (CO2e) footprint score in each category. This model is used globally and provides localised conversion factors for many countries, including Australia. We then take care to improve accuracy by using recent, Australian-specific data in place of global averages.
The CO2e footprint data we use is based on ‘full life-cycle analysis’, meaning it takes into account the CO2e produced during material processing, manufacturing, distribution, use, recycling & final disposal of the things you consume. This paints a more complete picture of the effort and consequences behind consumer goods & services, allowing for more impactful decision-making when trying to reduce our carbon footprint.
Calculating the estimated impact of One Small Step programs & habits
We have made a series of assumptions about the impact of our existing carbon footprint reduction programs & habits. These are outlined here. All data sources listed are publicly accessible. We think the assumptions we’ve made to calculate program impacts are reasonable and also relatively conservative.
However we’ll be able to rapidly improve the accuracy of our assumptions with regard to program impacts when we introduce a feature that provides our users with more granular control over their personal carbon profile. Until then, wherever the onboarding profile lacks detail, we use built-in default assumptions about user behaviour and how often users carry out specific pro-environmental behaviour as a result of completing One Small Step programs & habits.
Impacts scale to fit your existing carbon footprint profile
For different users, actions will have different impacts. This is because One Small Step users have different carbon footprint profiles that affect the potential impact of different programs & habits.
Here’s an example of how this works:
Mike uses the One Small Step app. When he does the quiz, he reports that he is a regular meat eater. When Mike completes the ‘Discover Plant-based Food’ challenges and starts switching to vegan alternatives, we assume he commits to eating two vegan meals per month for 2 months. By calculating the difference in intensity of those vegan meals as compared to his current diet we are able to estimate his impact.
When Chrissy does the quiz, she reports that she is a vegetarian. By using her current diet in the calculation, we get a lower, but more accurate, potential impact for Chrissy than for Mike.
This convention is used wherever possible to help keep the total impact of completing programs consistent with who you are, and the sustainable habits you already have committed to prior to coming into the app.