All resources must be considered:
The risk of overlooking a resource and exploiting it until it is too late is too great. Certain resources must also not be saved at the expense of other resources (e.g. clearing primeval forests for biofuels to save CO2 emissions). The overall consumption of resources must decrease.
To represent the value of resources, I assume a gardener who is responsible for all ecosystems and resources on our planet and sells us resource surpluses. The gardener represents the interests of the garden and is a business partner for us humans. A gardener and the image of a garden illustrate the resource limitations of the perceived immeasurable size of our earth. A gardener is less abstract than "nature", "ecosystems", etc. As a person she has interests and can make demands.
The gardener wants to stabilize and restore the ecosystems. It strives for perfect sustainability. It does not want to restrict or even control us unnecessarily. In fact it’s quite the opposite: She is well-disposed towards us and wants us to persist. With the garden she also protects us humans. She wants to inspire and motivate us to develop sustainable behavior and technologies.
Ideally, the gardener would estimate the resources generated by the garden per period (month) and determine what proportion can be made available to us. She measures the value of resources in her own currency REU (Resource Equivalent Unit) and gives this sum equally to all humans.
Whenever we use or endanger resources, we have to pay from the REU budget given to us.
The REU payment results in all products and intermediates receiving a second price in REU. No matter how long and complex the value chain is, REU costs are passed on from the extraction of resources to the final consumer. The REU price estimatesthe environmental footprint for each individual product.
Since the monthly REU budget is limited, there is a need to develop and purchase products that have low REU costs. This corresponds exactly to the optimization mechanisms that have so far worked with the classic money costs and high accuracy. Our entire economic activity is given a second optimization goal.
What is essential for the new currency is that it is independent of our traditional money and that it represents limited resources with a limited REU budget, detailed justifications can be found in Chapter 4.
At the moment, humanity consumes about 1.6 times as many resources as are created , in some countries even much more. If the REU budget were to correspond exactly to the available surplus, many people would become insolvent a few months before the end of the year and would not be able to use any further resources. That is why the gardener will have to compromise at the beginning and will be much more generous. She estimates the current resource requirements, evaluates them in REU and pays out the REU budget. So in the first moment we could go on living beyond our means.
But the REU budget is continuously being reduced so that resource-conserving products become more attractive. Earth Overshoot Day will shift towards the end of the year until there are even resources left. This means that we live sustainably and ecosystems are recovering.
The gardener acts like a company that sets the price for its products. However, there are important differences: a company will not give its customers the money to buy the products beforehand, the gardener will. The gardener also does not aim to increase sales or profits. On the contrary, she doesn't really want to sell anything, because that is always associated with damage to the garden. It will not and cannot increase the production of resources to flood the market with a successful product and maximize its REU revenue. Her first goal is the preservation of the garden and the as a vision she wants human to persist.
In order to make clear the dimension of environmental risk and our responsibility, I push up Chapter 9.19.1. To simplify matters, I only consider CO2 emissions, even if in principle all relevant resources must be taken into account.
If it is assumed that everyone would have a budget of 1000 REU per month and all people together would have to pay the CO2 emissions of 2012 (34.5 giga tons) with this budget, this would result in a price of 2.43 REU for every kilo of CO2. And that is a very generous offer, since CO2 emissions would have to be much lower to slow climate change. All the more these facts are disturbing therefore:
One economy scheduled flight Stuttgart to Barcelona and back causes 736 kg CO2 emissions  i.e. 1788 REU would have to be paid for this flight. That's almost a 2-month REU budget.
A car produces approx. 15kg CO2 per 100km. With an annual mileage of 12.000km, this corresponds to 4,374 REU, which is more than 1/3 of the annual budget. The production of a passenger car is not even considered and bursts the annual budget completely.
Even more impressive is the fact that the annual per capita emissions in India are only 1600 kg CO2, i.e. an Indian would have to pay 3,888 REU per year for his total CO2 emissions, and would have an unused budget of 12,000 - 3,888 REU = 8,112 REU at the end of the year. He could sell this REU amount to other people with higher resource consumption. The price would be regulated by supply and demand, although of course it would be much better if everyone tried to stay within their budgets.
With these figures it becomes clear how many people consume very few resources and who has the actual responsibility.
If the price per kilo of CO2 doubles over time, CO2 emissions will have to be halved, because we could not pay for more CO2 emissions with an unchanged budget. In the transition period there would be a very strong motivation to save CO2.
The prices seem to be very high, but they reflect exactly the value of the CO2 resources and for amount of CO2 each individual is responsible for.