In 2019, climate commitments were almost entirely self-reported: employers asked staff to fly less, cities asked residents to drive less, but nothing stopped anyone from simply ignoring the target once it became inconvenient. Doconomy, a Stockholm fintech, wanted a personal carbon budget that behaved like money — enforceable, not aspirational. Carbon accounting existed only as after-the-fact inspection: annual footprint reports, voluntary offset marketplaces, none of it touching the actual moment of decision, the purchase itself.
Doconomy partnered with Mastercard, which supplied the Åland Index — a database translating transaction categories and amounts into estimated CO2 emissions — and worked with ad agency RBK Communication on the product. Rather than building new tracking infrastructure, they attached the carbon calculation to the card network's existing authorization step, the same instant a bank already approves or declines a purchase for insufficient funds.
Piggybacked on the card network's existing authorization step: each purchase's CO2 footprint is tallied against a personal limit, and once hit, the card declines.
The authorization step already enforces spending limits, so adding carbon made it equally binding.
Piggybacking on existing card infrastructure avoided building new enforcement systems.
Real-time calculation made the limit tangible at the moment of purchase.
The decline was a familiar, trusted mechanism, increasing acceptance.
Enforce soft targets at the point of transaction using existing rails, not self-reporting.
Launched in Sweden in April 2019 and won the Cannes Lions Creative eCommerce Grand Prix two months later, but real-world uptake stayed small: reporting put registrations for the pilot card at roughly 9,000 users in Sweden, nowhere near mass adoption. The DO Black card was discontinued in 2022 as the company's business model shifted.
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