I just read an article in The Guardian with the title “Climate change: website reveals which homes will be swamped by rising sea levels” . It turns out that someone has used some very accurate maps and the bathtub approach for assessing sea level rise in all of Australia! When you go to the website, you are asked to register and then are informed that it has too much traffic and they will let you know when you can have a look. I waited for a while and it finally let me in when I had almost forgotten what I was waiting for…

There is a disclaimer that you have to tick a box saying that you agree with which explains that this approach is just informative and that the method does not take into account that shorelines are dynamic etc…  (I just lost connection with the page and cannot copy/paste parts of the disclaimer here) Therefore this page cannot be used to make decisions and so on.

The bathtub approach is wrong and cannot be used. There are numerous references that state so. Shorelines are mostly dynamic and respond to sea level change, there are more accurate ways of studying coastal response to sea level. Several scientists have presented different ways of approaching coastal response to sea level rise, for example A/Prof Peter Cowell, a member of our research group, has focused most of his research in developing such models. Peter presented in the ICS2016 and his presentation was really well attended. Scientists of the NSW Office of Environment and Heritage also presented their research on coastal response to sea level rise proving that the bathtub approach does not work for sandy wave-dominated shorelines, or estuaries.

One of the keynote speakers in the ICS2016 that we organised, A/Prof Giovanni Coco made a brilliant presentation titled “How do we best model eco-geomorphic environments and what can we actually predict?” . Giovanni is one of the world leaders in biomorphodynamics which studies two-way interactions (feedbacks) relating biology, morphology and physical forcing. He was adamant and he repeated it several times: “the bathtub doesn’t work”. He also said, quite accurately that “vegetation is more than a friction factor“, but that is something that we can discuss another day.

-Ana