Climate change is a fact even though some governments are trying to deny at all costs. In a new research in Nature Communications, scientists from the University of Central Florida claim that a flood level with a one-percent chance of occurring in 2017 (also known as a 100-year flood) will, in some parts of the world, have a 50- or even a 100- percent chance of occurring in 2050. This is absolutely relevant revelation will probably change our approach to flooding risk analysis.
Small but inevitable rises in sea level will double the frequency of severe coastal flooding in most of the world with dire consequences for major cities that sit on coastlines, according to scientists. Climate change is causing sea levels to rise at about 4mm per year, as ice caps melt and the oceans warm and expand. Some people believe that the rise in sea level is a direct issue to worry about but the truth is that our coastal infraestructures are prepared for this. The true point is that the rising level gives a higher starting point for the storm surges and waves that can overwhelm these coastal defences.
This study shows how even small changes in mean sea level can significantly increase the frequencies with which critical thresholds are exceeded. The reason of this fact is that there is a non-linear dependence between mean sea level and damage caused by the storm surge.
The new statistical model developed considers the uncertainties of what we know about extreme floods today and the results show that the old model underestimated predicted flood rates, in particular along the West Coast of both North and South America, in Southern Europe, and in Australia. Therefore, it seems that people on many more coastlines of the world will see extreme floods become common within a few decades.
The research shows that most at-risk areas were in the low latitudes, where tidal ranges are smaller meaning sea level rise is proportionally more significant. The United States loses 82 lives and $8 billion to floods each year. If we are not able to prevent these damages, it is clear that the consequences will be expensive and dangerous all over the world.
Moreover, in the future we will not only be threaten by sea but also by rivers. Many coastal cities have grown around or close to a river and an increase on the mean sea level will complicate its discharge to the sea. I will try to explain further this idea on my next post.
It is important to note that major flood protection systems can take decades to plan and implement. That´s why if we can foresee that by 2050 things are already so critical, that means we should probably take measures right now.