ACE sea-level rise expert Dr John Hunter is removing some of the guesswork for engineers, planners and developers of new coastal buildings. Dr Hunter’s latest analysis combines two sets of information – the current frequency of flooding events and estimates of sea level rise. From this combination a single figure is calculated, defining the height allowance required for a building to be safe from future flooding.  The technique was published in November in the journal Climatic Change and Dr Hunter is now the basis of guidance being provided to the Tasmanian Government. The technique addresses the impact of rising sea levels by allowing planners to calculate where buildings need to be situated so that flooding by the sea is no more common in the future than it is today. Both the frequency of flooding events and the degree of sea-level rise hold significant uncertainties, but putting both elements together delivers planners a much more useful height allowance figure.  “The method is objective in that once you have the input numbers - one number defining the storm surges and tides at a given location, and two more numbers defining the best estimate of future sea-level rise and its uncertainty - there is only one answer for the allowance,’’ Dr Hunter said. “A bonus of this method is that the answer does not depend on the degree of precaution - it simply says that this is what you need to do in order to keep the same level of precaution that you have at present.” Dr Hunter has used tide gauge data from all over the world and has therefore been able to compare the frequency of coastal flooding events on a global scale. “We have showed these results for Australia before, but the paper also shows (and tabulates) the results for a global data set,’’ Dr Hunter said. Owners of beach infrastructure are already feeling the effects of sea level rise. For example, in November a report by GeoSciences Australia for Surf Lifesaving Australia found that extreme tides and weather conditions were threatening more than half of Australia's surf live saving clubs.

---