It is now accepted beyond doubt that historical and future greenhouse gas emissions and changing land use had and will have a significant effect on the Earth’s climate. The IPCC Fifth Assessment (AR5) report concluded that “warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia”. Furthermore, it is extremely likely (95–100% probability) that human influence was the dominant cause of global warming between 1951 and 2010. The United Nations has declared that the world experienced
more unprecedented high-impact climate extremes in the first decade of the 21st century than in any previous decade. Understanding of the potential for additional climate change needs to be continually refined, improved and updated to reflect the best available science and emerging understanding of global social and economic development and exploit the advances in information technologies.

Accurate climate projections, produced by climate models, can assist policymakers to plan for and adapt to the adverse effects of climate change. The EC-Earth CMIP6 data, produced as part of this report, provide sharper and more accurate projections of the future global climate and will lead to a better understanding not only of the physical climate system but also of the climate impact on societies. The EC-Earth data will assist in addressing all three of the CMIP6 broad scientific questions and a number of the grand challenges of the World Climate Research Programme. The datasets will enhance the overall understanding of anthropogenic climate change on a global scale and will assist in presenting a case for a follow on to national targets, such as the United Nations COP21 Paris Agreement. This study ensures that Ireland remains at the forefront of global climate change research and continues its involvement with the Coordinated Regional Climate Downscaling Experiment (CORDEX) and CMIP6 and IPCC AR6 reports.

All CMIP6 EC-Earth data were published on the Irish Centre for High-End Computing (ICHEC) Earth System Grid Federation (ESGF) node. ESGF is an international collaboration between climate centres with a mission to support CMIP6 and future IPCC assessments. The data produced as part of the current report will be analysed by the international research community for inclusion in the upcoming IPCC AR6 reports. In addition, the EC-Earth simulation data will be used as a basis for more focused regional climate impact studies, such as national downscaling projects and the international CORDEX research community.