Simon They made many different claims over the years regarding this, also because their product changed so often. With the original Green Card, you could after all plant 2 trees per 100 Euros if you also paid for a Premium subscription. There is also not one fixed number for how high the average CO2 footprint is, so with that in mind I could see it kinda working out... 1000 Euros (and a bit more) every month would've netted you close to the 24 trees a month that you need to get CO2 neutral in 2 years with the older offering. There is also a blog article from the "SuperGreen" era where it says you can get CO2 neutral in around 5 years. Which is what it actually takes if you spend 1000 Euros every month under the current offering of 1 tree per 100 Euros.
