'Earth Credit' is inspired from the 'carbon credit' that we already have to curb the release of greenhouse gasses to the environment. For every item produced by a company, an 'Earth Credit' is assigned to it, dependent on how much its production actually harms the environment. The more it harms, the higher the 'Earth Credit' is.
On the other hand, everyone is given a number of 'Earth Credit' to be spent annually. Since everyone in this world has an equal right to live in this world, everyone is given an equal amount of 'Earth Credit' as well. To earn more, people can help out in various efforts that benefit the environment through their time or donation.
For people who have more than enough 'Earth Credit', they can either donate it back to help preserve the Earth or exchange it for real cash for those who need it more.