Q1. What are the contributions mentioned in the paper "Enhancing life cycle impact assessment from climate science: review of recent findings and recommendations for application to lca" ?
36 Since the Global Warming Potential ( GWP ) was first presented in the Intergovernmental Panel on 37 Climate Change ( IPCC ) First Assessment Report, the metric has been scrutinized and alternative 38 metrics have been suggested. The IPCC Fifth Assessment Report gives a scientific assessment of 39 the main recent findings from climate metrics research and provides the most up-to-date values 40 for a subset of metrics and time horizons. The objectives of this paper are to perform a systematic 41 review of available midpoint metrics ( i. e. using an indicator situated in the middle of the cause42 effect chain from emissions to climate change ) for well-mixed greenhouse gases and near-term 43 climate forcers based on the current literature, to provide recommendations for the development 44 and use of characterization factors for climate change in life cycle assessment ( LCA ), and to 45 identify research needs. This work is part of the ‘ Global Guidance on Environmental Life Cycle 46 Impact Assessment ’ project held by the UNEP/SETAC Life Cycle Initiative and is intended to 47 support a consensus finding workshop. In an LCA context, it can make sense to use several 48 complementary metrics that serve different purposes, and from there get an understanding about 49 the robustness of the LCA study to different perspectives and metrics. The authors propose a step-by-step 50 approach to test the sensitivity of LCA results to different modelling choices and provide 51 recommendations for specific issues such as the consideration of climate-carbon feedbacks and 52 the inclusion of pollutants with cooling effects ( negative metric values ).