Every day, you carry out an average of 6 to 8 bank transactions: coffee, groceries, streaming subscription, fuel, online order... Each of these expenditures is also a climate decision. Together, your bank statements from the last 12 months contain a precious and largely untapped piece of information: your real carbon footprint. Here is why your bank spending is the most accurate mirror of your climate impact.
The link between money and CO2: an often-overlooked reality
Our economy is deeply carbon-intensive. Every euro spent, regardless of the category, generates a greater or lesser amount of CO2 depending on what it funds. A euro spent on a plane ticket does not have the same climate impact as a euro spent on books or vegetables. But in both cases, there is an impact.
Researchers have developed emission coefficients by spending category that allow euros to be converted into kilograms of CO2. For example, according to the work of ADEME and researchers at the University of Leeds, each euro spent on:
- Fuel generates approximately 2.8 kg of CO2e
- Red meat generates approximately 0.8 kg of CO2e
- Air travel generates approximately 1.5 to 3 kg of CO2e
- Digital services generates approximately 0.1 kg of CO2e
- Plant-based food products generates approximately 0.2 to 0.4 kg of CO2e
Applying these coefficients to all of your bank transactions over a year produces a carbon footprint estimate that is far more accurate than a checkbox questionnaire.
How open banking makes this possible
The European PSD2 regulation (Payment Services Directive 2), which came into force in 2018, opened a new era: that of open banking. It requires banks to allow authorized third-party providers to access their customers' transaction data, subject to the explicit consent of those customers.
To understand the basics of this system, our article on open banking — a simple guide to understanding it all is an excellent starting point.
In practical terms, open banking allows third-party applications to:
- Automatically retrieve your transaction history
- Categorize each expense by type (food, transport, housing, etc.)
- Apply carbon emission factors to each category
- Generate a real-time dashboard of your carbon footprint
No more filling out long questionnaires. Your banking data does the work for you.
What your bank statement reveals about your footprint
The major emission categories that statements reveal
An analysis of aggregated (anonymized) French banking data conducted by researchers in 2023 reveals recurring patterns:
- Fuel spending (gas stations) often represents the top emission category for households in suburban or rural areas
- Supermarket purchases indirectly reveal dietary habits: an average basket with regular meat vs a vegetarian basket do not have the same impact
- Plane tickets, even rare ones, create massive emission spikes that can represent 30 to 50% of the annual footprint
- Recurring subscriptions (streaming, cloud, video games) have a low but cumulatively significant impact
Hidden emissions in everyday purchases
Some emissions are hidden in spending categories you would not immediately suspect:
- A florist purchase may conceal flowers flown in from the Netherlands or Kenya
- A restaurant meal has a highly variable carbon footprint depending on the menu (steak or salad)
- An Amazon purchase could correspond to a book (low impact) or an electronic device (high impact)
This is where the limitation of purely transactional analyses lies: the spending category is not always granular enough. The best applications cross-reference transaction data with other sources (merchant name, amount, history) to refine the estimate.
Open banking and environmental footprint: the combination that changes everything
The combination of open banking and carbon calculation represents a paradigm shift in how we understand our environmental impact. To explore how this union between banking data and climate issues is reshaping our behaviors, our article on the environmental impact of open banking covers this topic in detail.
"Spending data is the best proxy for individual carbon footprint available at scale. It finally allows us to move beyond biased self-reported surveys and have a real signal of climate behavior."
— I4CE think tank report, 2023
Concrete advantages of spending-based carbon tracking
- Accuracy: the calculation is based on your actual transactions, not on statistical averages
- Automation: no manual entry, everything is derived from your existing data
- History: you can visualize the evolution of your footprint month by month, year by year
- Hotspot identification: the interface highlights your most carbon-intensive categories to help prioritize your efforts
- Comparison: some tools allow you to compare yourself to similar profiles (same region, same income)
Limitations and precautions to take
This approach has limitations that you should be aware of:
- Accuracy is not perfect: emission factors by category are averages, not exact measurements
- Some emissions escape spending data: the carbon footprint of your public services or taxes is not captured
- Cash spending entirely escapes the radar: untracked expenses distort the calculation
- Privacy: access to your banking data should only be granted to trusted providers, authorized by the ACPR (French Prudential Supervisory Authority)
What to do with this information?
Knowing your "carbon map" is not enough. The challenge is to turn it into concrete actions. The best applications go beyond display and offer:
- Personalized challenges based on your highest emission categories
- Lower-carbon alternatives for each spending category
- Automatic offset options for unavoidable emissions
- Progressive reduction targets with tracking over time
Conclusion: make your banking data speak for the climate
Your bank statements are a goldmine of information about your environmental impact. By allowing a trusted application to analyze this data, you get a complete and personalized view of your carbon footprint in just a few minutes — without manual entry, without approximations. This is the democratization of the personal carbon assessment: what only large companies could afford to do ten years ago is now accessible to everyone, free of charge, from their smartphone.