Introduction
Despite all the international efforts to reduce greenhouse gas emissions, the concentration of carbon dioxide in the atmosphere continues to increase at a steady rate. Even the full commitment of policymakers against climate change and implementation of the Paris Agreement would not be enough to prevent global warming by the end of this century. Climate change is defined as a global commons problem with temporal and spatial dimensions where the differentiation of responsibilities and vulnerabilities threatens global action (Gardiner, 2006).
To solve the problem of spatial and temporal dimensions, scientists use climate models to assess the costs of action and inaction both globally and also in a time horizon until the end of the 21st century. At the core of these models lies human activities creating additional radiative forcing to earth with scale on the same degree compared to natural radiative forcing – mainly from solar and geochemical cycles – causing climate variability which started long before human civilizations appeared on earth. Climate change was perceived positively as prevention of another ice age at the beginning of the 20th century whereas scientists nowadays also consider climate extreme events such as the stopping of Thermo-haline circulation or the albedo effect from melting of continental and sea ice in polar regions (Hulme, 2008). However, both the temporal and spatial distance of these events and also the uncertainties underlying the empirical evidence leave us in a situation of difficulty to act.
As the future is uncertain, modellers have developed climate future narratives as a baseline to cover the different pathways through which human societies as a whole could evolve until the end of the 21st century. These directions are referred to as shared socioeconomic pathways which are characterized depending on the level of challenges to climate mitigation and adaptation. This is the problem of the utilitarian where climate mitigation efforts require the reduction of total welfare whereas increasing welfare could also be directed to climate adaptation efforts (Berdinesen, 2018). However, decision making for welfare maximization which doesn’t consider environmental externalities and doesn’t act according to environmental virtues risk losing everything in case of a climate extreme event.
Also as current greenhouse gas emissions will determine the extent of climate change in the future, the temporal dimension of actions require the development of additional shared policy assumptions depending on largely uncertain discount rates used for comparing the welfare of current and future generations (Cafaro, 2011). Placing nature as our locus of environmental value requires also the fair distribution of resources between humans and other species while respecting the climate as life supporting and regulating system. Despite human civilizations have consumed nearly half of the global carbon budget in the atmosphere defined by climate target under the Paris Agreement (Alcaraz et al. , 2019), we have not been able to develop feasible environmental ethics towards our climate which supported our welfare during the Holocene geological epoch.