Towards a comprehensive characterization of evidence in synthesis assessments: the climate change impacts on the Brazilian water resources

• Published in: Climatic change Vol. 155; no. 1; pp. 37 - 57
• Main Authors: Borges de Amorim, Pablo, Chaffe, Pedro B.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.07.2019; Springer Nature B.V
• Subjects: Atmospheric Sciences; Climate change; Climate Change/Climate Change Impacts; Communication; Confidence intervals; Consistency; Earth and Environmental Science; Earth Sciences; Environmental assessment; Environmental impact; Hydrologic models; Hydrologic regime; Hydrology; Intergovernmental Panel on Climate Change; International organizations; Synthesis; Uncertainty; Water resources; Brazil
• ISSN: 0165-0009; 1573-1480
• DOI: 10.1007/s10584-019-02430-9

The Intergovernmental Panel on Climate Change (IPCC) has put a lot of efforts to describe uncertainties and to judge the confidence level of its major conclusions. Despite a guidance to communicate uncertainty, the assignment of confidence is not sufficiently clear and, thus, hard to be reproduced by the extern community. By conducting a synthesis assessment about the impacts of climate change on the Brazilian water resources, we identified an opportunity to illustrate the characterization of evidence as adopted in IPCC reports. We propose a method to describe the evidence from model outputs wherein the quality and amount of studies, as well as the consistency among their conclusions, are subject of a transparent rating procedure. In summary, the more comprehensive the study in sampling uncertainties, the higher its quality . Likewise, the amount and consistency among conclusions is assigned in a systematic way. The method is applied for synthesizing a collection of 42 peer-reviewed articles. It reveals important aspects about the evidence of the potential impacts of climate change in the Brazilian water resources, such as changes into a drier hydrological regime. However, the use of multi-model ensemble, the evaluation of models, and the observational data is limited. The proposed method enables consistent communication of the degree of evidence in a transparent, traceable, and comprehensive fashion. The method can be used as a tool to support experts on their judgment. The approach is reproducible and can guide synthesis work not only in Brazil but anywhere else.