Compte CO2 - Headband Illustration

The Green-Euro, a monetary innovation that is more than 10 years old

The idea of introducing an incentive mechanism, rather than a punitive one, is at the origin of the invention of the Green-Euro

1990 – 2010. Palavers

20 years of exciting discussions and experiments with passionate researchers on climate change and its challenges.

2010. Incorporation of 450 Co.

This is the beginning of the move to action. By creating the 450 Company (like 450 ppm, the CO2 concentration threshold that should not be exceeded to have a 50/50 chance of limiting climate change to 2°C), the fundamental idea is to encourage and reward those, including companies and local authorities, who reduce their CO2 emissions with carbon credits..

2012. Approval of the methodology for calculating CO2 emission reductions

The CO2 methodology is approved by the French government (DG Treasury and DG Energy Climate), as well as by the UNFCCC in the framework of the law on "domestic projects" and the Kyoto Protocol. The scope of the calculation of CO2 emission reductions is limited to Buildings PLUS Transport, in order to have accurate measurements. This also represents about half of Europe's emissions.


With the support of Michel Rocard, former Prime Minister, and Jean-Pierre Denis, Chairman of the Crédit Mutuel Arkéa group, the CO2 Savings Account is open to the general public. Households can calculate their CO2 emissions, receive carbon credits, and spend them in a network of partners. The currency is called "Kg of CO2". We thought it would help to materialise both climate change (we don't see the CO2, it's for 2050), and the currency.


Let's simplify, let's simplify... This is the beginning of our reflections on User eXperience (UX). The name of the site is shortened, and the currency is now called "CO2". When I reduce one ton of CO2, I receive 1000 CO2, which are worth 44.60 euros (44.60 is the value of the carbon tax).

2018. Switch to €O2

There is no longer any need to explain climate change to our users, as the media are now talking about it all the time. Explaining what a currency is, however, remains a tricky exercise. To simplify things, and to avoid confusion between money and CO2 reductions, the currency is now called the €O2. When I reduce one tonne of CO2, I receive 1000 €O2, which is worth 44.60 euros. Birth of the CO2 Account App available on the Stores. 450 wins two European calls for projects and receives funding from the European Commission (H2020 programme) to design and distribute a currency that also promotes energy efficiency.

2020. Green money and the Euro-Green

Towards even greater simplification. To win the climate battle, it is not finance or banks that must become green, but money! And since everyone uses the euro, without knowing exactly what it is, let's call our currency the Euro Green (€G). Let's also do away with the complex calculations: one euro-green is worth one euro. Full stop. When I reduce one tonne of CO2, I get 44.60 euro-greens. One euro-green is one euro, backed by a reduction in CO2 emissions.

2022. Euro-Green, the first retail central bank digital currency?

All central banks are now looking at the possibility of using crypto-currencies, and are looking for use cases. We have responded to many calls for projects from these central banks, with a euro-green that would be registered on a blockchain. There would be a lot to gain for central banks (before GAFAMs get hold of the subject), for States (in France alone, public spending could be reduced by 19.8 billion euros, not to mention the Affaire du Siècle case where the court has so far condemned in 2021 the French State for climate inaction), and for all of us, because each euro-green is associated with a reduction in CO2 emissions. So if many of us download the CO2 Account App, and circulate euro-greens, we will succeed in generating a lot of CO2 emission reductions. And win the climate battle.

Compte CO2 - Footer Flower Illustration