World map. The map at the top shows all regions of the portal. Each of the small coloured hexagons stands for one variable, its colour for the sector (the same colours as in the list of sectors below). So you see at a glance how many variables a region offers in which sectors; the mouse pointer pushes the hexagons aside. A click on a region opens a window with a short description and its sectors with the number of variables; a click on a sector leads to the map of the region.

Sector overview. Below the map the sectors are listed with the number of regions that offer them. A click opens an overview: one row per variable, one column per region, with small preview maps. So you can compare which variables exist where; a click on a preview opens the map of that variable in that region directly.

Header and footer. At the top right you choose the language and find „Old design“, the previous version of the portal. At the bottom you find the news, the imprint, data privacy, contact and the newsletter.

How maps, time line, settings, diagrams and tables are used on the region pages is explained there under Usage in the top bar.

Observations and simulations. For the past the portal shows observations: for Germany and Bavaria values interpolated from the stations of the German Weather Service, for the other regions the observation-based global data set W5E5. They are the best-founded basis. Next to them are historical simulations: climate models recompute the past, and the comparison with the observations shows how well they reproduce the climate of a region. The future projections continue these model runs under different scenarios. The simulations are adjusted to the observations (bias adjustment, ISIMIP3BASD) to reduce systematic model errors.

Uncertainties. Projections are not forecasts. They depend on the scenario, on the climate models and, for climate impacts, also on the impact models; single models and methods have known weaknesses, especially for precipitation and extremes. The portal therefore shows means over 10 or 30 years and the spread of the model ensemble (10th to 90th percentile), not the value of a single year.

Scenarios. Most regions use the scenarios of the latest model generation (CMIP6), which combine socio-economic pathways with emissions: SSP1-2.6 (sustainable development, strong climate protection), SSP3-7.0 (regional rivalry, high emissions) and SSP5-8.5 (fossil-fuelled development, very high emissions). For Germany and Bavaria the data are based on the regional model ensemble EURO-CORDEX of the previous generation (CMIP5) with the scenarios RCP2.6 (strong climate protection, about 2 °C) and RCP8.5 (very high emissions).

Data sources.

• Global climate models from ISIMIP (Inter-Sectoral Impact Model Intercomparison Project, coordinated by PIK), CMIP6, for most regions.
• Regional climate models from CORDEX (Coordinated Regional Climate Downscaling Experiment): for Germany and Bavaria the EURO-CORDEX ensemble of combinations of global and regional models (17 runs for RCP8.5, 7 for RCP2.6), for Jordan in addition CORDEX precipitation at high temporal resolution (RCP8.5).
• Further climate data sets for single regions, e.g. RAIN4PE (precipitation) in Peru.
• Climate impacts from ISIMIP: global hydrological models (water) and crop and vegetation models (agriculture) of several research groups.
• PIK models: the eco-hydrological model SWIM (water in Germany, Europe and the Congo basin), the vegetation model LPJmL (forests and biodiversity in the Amazon and Ethiopia) and the statistical yield model ABSOLUT (silage maize and winter wheat per district in Germany).
• Derived indicators: many variables are calculated by KFO itself from the daily climate data, e.g. hot days and frost days, growing degree days, climatic water balance or photovoltaic yield.

Which data and models are used for a region in detail is described there under data info.

Climate Impacts Online is for everyone who wants to know how the climate and its impacts may develop in a region – no background in climate modelling needed.

• School and university students explore climate change in their own or a distant region, compare scenarios and periods and use maps and diagrams for presentations and projects.
• Teachers find clear maps, diagrams and tables for lessons in geography, biology, physics or politics, for very different regions of the world.
• Planners of adaptation measures in municipalities, districts, regional and state planning, water management, forestry and agricultural administrations get a first assessment down to the district level; the data can be downloaded.
• Professions that depend on weather and climate: agriculture, horticulture, wine and fruit growing (e.g. frost days, growing degree days, Huglin index, dry days, yields), forestry (forests and biodiversity), energy (photovoltaic yield, wind), tourism (snow days), health and care (hot days, tropical nights, heat stress), construction and urban planning (heavy precipitation, heat).
• Media, policy and administration use the portal for a quick overview and for graphics on regional climate impacts.
• Development and international cooperation finds data for regions in Africa, Asia and South America, in the languages of these regions.
• Anyone interested sees what climate change may mean for their home town, their garden or their holiday destination.

The maps show means over 10 or 30 years and the spread of a model ensemble, not a weather forecast. For planning, read the data info of the region as well.