Climate change effects on major drivers of harmful algal blooms (HABs): best management practices and HAB severity

SUMMARY This technical report documents the description and findings of the case study entitled “Climate change effects on major drivers of HABs in Lake Erie in the United States” implemented by the National Center for Water Quality Research (NCWQR), Heidelberg University, Ohio, USA. This report is divided into five main sections: 1) description of the case study, 2) potential adaptation measures, 3) contact, 4) data production and results, and 5) conclusions. The Copernicus Climate Change Service (C3S) platform provided downscaled and bias-corrected climate indicators in which the locally-produced climate indicators in the Western Lake Erie Basin can be compared and verified with. The platform also provided an easy access to climate indicators and essential climate variables (ECV’s) that could be used to develop and test other mitigation approaches. The results showed that increased temperature and precipitation would increase the annual occurrence of severe algal blooms to 24% in the 2050’s. However, the implementation of best management practices (BMPs) could reduce this risk down to 12%, similar to the past 16 years. Currently recommended mitigation approaches on top of the existing practices are enough to maintain the risk level of severe algal blooms occurrence even with climate change effects in the future. However, “out-of-the-box” mitigations are necessary to further lower the risks of severe algal bloom occurrence than the current levels