Abstract
Baltic Earth (https://baltic.earth) succeeded the Baltic Sea Experiment (BALTEX) in June 2013, and is currently one of the GEWEX Regional Hydroclimate Projects (RHPs). It strives to coordinate and foster research in an international and interdisciplinary network of institutions and scientists working
on regional Earth system issues in the Baltic Sea region. The BALTEX Assessment of Climate Change for the Baltic Sea Region (BACC, 2008) was among the first regional assessments that took the Intergovernmental Panel on Climate Change (IPCC) example to the regional level, but with a dedicated bottom-up strategy. No countries were officially involved, only scientists from the region, from different countries and disciplines. The idea was to compile a “synthesis of material drawn comprehensively from the available scientifically legitimate literature (e.g., peer reviewed literature, conference proceedings, reports of scientific institutes). Studies whose results and conclusions cannot be reconciled with a consensus view but which are of a good scientific and technical standard should be taken into account. The assessment should thus encompass the knowledge about what scientists agree on but also identify cases of disagreement or knowledge gaps” (https://baltic.earth/bacc; BACC II tasks and responsibilities). The assessment was published as a comprehensive textbook with Springer, by more than 80 authors from various disciplines. It is separated into three parts: past climatic changes, possible future climatic changes, and the manifold impacts on terrestrial, freshwater and marine ecosystems of the region. An important aspect already in this early assessment was the close collaboration with the Helsinki Commission (HELCOM), which is an intergovernmental organization to protect the Baltic Sea environment and to give associated scientific advice and recommendations to the contracting partner countries. As such, it acts as a regional science-policy interface. Seven years later, the Second Assessment of Climate Change for the Baltic Sea Region (BACC II, 2015) was published, this time with more than 140 authors, and updated content, including new aspects like postglacial climate change, socio-economic aspects of climate change, and drivers of regional climate change, including aerosols and land use. Both assessment reports, published as textbooks, represent excellent archives of the contemporary knowledge of climate change and its impacts in the Baltic Sea region, and are excellent study books on the environment of the Baltic Sea region.
