Energy and transport research towards net zero targets and climate change mitigation. A systematic review of evidence communication for policy makers

Scientific studies often put forward policy recommendations (PRs) to bridge the gap between science and policy making. Climate change is one of the areas that PRs can be useful and have major impact, but only if they are based on scientific findings and are communicated trustworthily. The objective of this systematic review is to appraise the quality of PRs in the areas of green energy and transportation. Four databases (Web of Science, Scopus, GeoRef and GreenFile) were searched from 2019. Studies with an environmental focus in the areas of green energy (wind power and hydrogen energy) and transportation that included PRs for tackling climate change or reaching net zero targets were included. The novel Evidence Communication Rules for Policy (ECR-P) critical appraisal tool was used to assess the individual study quality, specifically targeting PRs. The Collaboration for Environmental Evidence Critical Appraisal Tool (CEECAT) was also used. Findings were synthesized narratively based on ECR-P. Twenty-three studies were included, most focusing on wind power, followed by hydrogen energy and transportation. The majority of studies used econometric and empirical modelling. According to CEECAT, study quality was found to be medium to poor. ECR-P was piloted and validated, the rating results indicated poor quality of PRs across all studies. The areas addressing the papers inherent bias towards advocacy against providing information and to disclose uncertainties were found to present most concerns. Communication quality was markedly better regarding study findings and conclusion than PRs. Researchers must use the same scientific rigour and reporting standards in PRs as in any other section of their studies. A reporting guideline for scientific-based PRs could be of great assistance. More research in other disciplines is needed to validate our results and provide further data.