Development of climate tipping damage metric for life-cycle assessment - the influence of increased warming from the tipping

Purpose: The multiple climate tipping points potential (MCTP) is a novel metric in life-cycle assessment (LCA). It addresses the contribution of greenhouse gas emissions to disturb those processes in the Earth system, which could pass a tipping point and thereby trigger large, abrupt and potentially irreversible changes. The MCTP, however, does not represent ecosystems damage. Here, we further develop this midpoint metric by linking it to losses of terrestrial species biodiversity at either local or global scales.
Method: A mathematical framework was developed to translate midpoint impacts to temperature increase, first, and then to potential loss of species resulting from the temperature increase, using available data on the potentially disappeared fraction of species due to a unit change in global average temperature.
Results and discussion: The resulting damage MCTP expresses the impacts on ecosystems quality in terms of potential loss of terrestrial species resulting from the contribution of GHG emissions to cross climatic tipping points. The MCTP values range from 2.3·10^–17 to 1.1·10^–15 PDF (potentially disappeared fraction of species) for the global scale and from 2.7·10^–17 to 1.1·10^–15 PDF per 1 kg of CO₂ emitted for the local scale. They are time-dependent, and the largest values are found for emissions occurring between 2030 and 2045, generally declining for emissions occurring toward the end of the century.
Conclusions: The developed metric complements existing damage-level metrics used in LCA, and its application is expected to be especially relevant for products where time-differentiation of emissions is possible. To enable direct comparisons between our damage MCTP and the damage caused by other environmental impacts or other climate-related impact categories, further efforts are needed to harmonize MCTP units with those of the compared damage metrics.