Ethics is based on the assumption of equal rights and obligation for all humans. The resulting ethical guidelines, partially manifested in the laws, have to be obtained by discourse aiming at ensuring maximum wellbeing for everyone while minimizing the restrictions to our behavior.
Since human behavior influences the ecosystem of our planet earth, which in turn affects everyone, this feedback also has to be taken into account in the societal discourse. Our personal behavior, for which we are individually responsible, affects the wellbeing of everyone. It has to be realized that we don't have the right to only have rights. We also unavoidably have obligations, which here need to take e.g. sustainability into account.
A sustainability ethics has to take these hard boundary conditions into account, which can not be negotiated. Since the changes in our ecosystem will be rapid, we can not rely on traditions for our behavior or even traditions on how we develop and update an ethics. Instead it is upon us to actively foster a sufficiently fast discourse and to agree on new ethical guidelines that will foreseeably deviate from our previous traditions. It is these traditions that have got us into the current situation with its global challenges.
In developing a sustainability ethics, we can not rely on unanimity but have to move faster. Thus new strategies in the discourse between developed and less developed regions are required leading also to more flexible structure and mode of ratification of international treaties.
As living beings we have certain demands and desires. Living within a society, we have to realize and acknowledge that we are interacting continually with comparable human beings, which also have comparable demands and desires. We finally realize that not all of the demands and desires of all humans interacting can be fulfilled simultaneously. Some may even be conflicting. Thus, apparently, a way has to be found that allows to generate a situation, where the demands and desires may not be completely fulfilled but at least fulfilled to an acceptable degree. This is the basic for an ethics.
Realizing that the demands and desires are very individually personal, it is clear that ethical rules cannot be defined on absolute grounds. While some fundamental ethical rules like the right for unharmed life may be derived on very basic grounds, for more individual aspects a direct negotiation between the interacting humans is required. Only this way the individual aspects can properly be accounted for. This leads to the insight that a proper ethics has to include discursive elements, resulting in a discursive ethics. The goal of the discourse is to find an optimal balance between the possibly differing interests of different people. Since it is impossible that all people involved in each individual situation first engage in a discursive negotiation about the specific ethical rules to be applied, fundamental prototype ethical rules have been developed in the past, which finally culminated in the legal body of laws, which is binding within a society. That even these laws are based on discursive engagement of society is clear, since laws are continually changed induced by new insights or new situations that need to be covered.
Especially in a limited world, where induced by our actions we are hitting these limits, an ethics cannot only build on discourse per se. We also have to realize the consequences of our actions. This includes for example our individual actions inducing an increase in climate change or an increase in number of undernourished fellow humans. Since we are individually responsible also for what we individually contribute, it is required that in the discourse also the reactions of the ecosystem to our decisions and the resulting actions has to be included in the ethical considerations. Realizing that many of the consequences of our actions today like the climate change will stay with us for centuries to come, these ecological aspects need to be accounted for with a correspondingly high weight.
A sustainability ethics thus has to consider the best compromise between the individual interests of all humans and at the same time has to consider the consequences of the resulting changes of our ecosystem for each of us. While we can negotiate the compromise with our fellow humans, we can not negotiate with the ecosystem. The consequences of the ecosystem, which are induced by our actions, will inevitably happen. Thus, if we don’t change, the ecosystem will.
Interestingly enough, even in the UN Declaration of Human Rights obligations are mentioned, which assign duties to everyone so that it is and will remain possible that all humans can enjoy the universal rights defined in that declaration. Especially adequate food supply is one of the fundamental human rights, which directly relates back to the discussion on sustainability. These already existing and broadly accepted Human Rights thus can form a first basis for a sustainability ethics, if the duties are more generally realized as referring to individual responsibilities.
Until now, ethical guidelines and rules have been developing over long periods of time and became part of our culture. These ethical boundary conditions traditionally change only slowly, which as a consequence leads to laws being changed only now and then and often only in small steps. We have to realize that these traditional ways of coming to a generally accepted ethics will not work for our future. The changes will occur so quickly, that we are running out of time for the traditional approach. We thus need to actively foster the discourse and the coming to agreements. We essentially would need to change today to ensure wellbeing tomorrow. Sustainability ethics thus has to build on a broad consensus but possibly not on unanimity as is currently the case for example for the climate conventions. Requiring unanimity always leads to the slowest possible progress, which currently would be detrimental, since any veto has to be exhaustingly negotiated, only slowing down the process. Thus, binding international treaties need to be negotiated between the agreeing parties, which can then easily be extended to include new partners. Only with such a dynamic way of organizing the legal system between nations, we can be fast enough to cope with the challenges ahead. At the same time, such treaties may mean obligations on both sides, which are not just defining a finacial flux from developed into less developed regions, but can and should include all aspects of behavior discussed here, specifically also the number of children and nutritional habits.