UNIVERSITY OF TORONTO, CANADA: Researchers from the University of Toronto, University of Harvard and Rutgers University have found a way to identify the “sea level fingerprint” left by a particular sheet of ice – and possibly enable a more precise estimate of its impact on global sea levels, a key measure of global warming.

As the Earth’s climate warms, a melting ice sheet produces a distinct and highly non-uniform pattern of sea-level change, with sea level falling close to the melting ice sheet and rising progressively farther away. The pattern for each ice sheet is unique and is known as its sea level fingerprint.

These findings provide a new method to distinguish sea-level fingerprints in historical records of sea levels, from other processes such as ocean waves, tides, changes in ocean circulation, and thermal expansion of the ocean. Scientists around the world are trying to estimate both the current rate of sea level rise and the rates of ice sheet melting, and yet little work has been done to combine the two problems and answer these questions simultaneously. Researchers from the Universities of Toronto, Harvard and Rutgers sought out statistical techniques that had not previously been applied to this problem, and began developing the new method using data analysis techniques common in other fields such as engineering science, economics, and meteorology. The researchers then tested and refined the method by applying it to synthetic data sets. The tests provide important guidance for the application of the method to actual sea-level records.