In Research Focus 3, the scientific findings obtained at small (RF 1) and basin-wide (RF 2) scales will be combined with the factor time. IOW scientists are interested in finding out how the Baltic and its many processes have changed over the course of decades, centuries and millennia. On the basis of information describing past and current developments they will be able to make predictions about the future of the Baltic Sea and thus of comparable ecosystems. Of particular interest is the question how coastal and marginal seas respond to climate change and to intensive anthropogenic influences.

To be able to make these predictions, IOW scientists are developing computer models – virtual representations of the Baltic Sea – and setting these in high-speed motion into the future. As with the forecasts of the weather or stock prices, a computer model of the Baltic Sea becomes more reliable the more that is known about the past behavior of each contributing process. Therefore, to calibrate their computer models the scientists make use, on the one hand, of the IOW's extensive data set, covering a century of observations, and, on the other, the natural "archives" of the sediments, which offer an even further look into the past, to a Baltic Sea before the industrial revolution. Both sources of information are constantly being extended by measurements from buoys, probes, stations, satellites and research excursions, as well as by the latest analyses of sediment samples from the ocean floor, so that with each passing year scientists gain increasing insight into the Baltic Sea of the past. As a result, the accuracy of the forecasts made by the IOW's models increases in parallel.