Floating Islands?

Motivated by the recent devastating flooding in the North of England, I wanted to briefly explore potential mitigation mechanisms. With sea level increasing, and 650 million people projected to be at risk from storm surges by 2100, attention towards this area will become ever more critical. I have previously discussed the pros and cons of migration in offering one such mitigation mechanism for these changes, but this drastic ‘worst case scenario’ solution is by no means the only option.

The IPCC proposed three strategies for flood protection in their first assessment; protection, accommodation and retreat. Protection refers to the typical hard engineering methods, such as breakwaters and sea defences. Accommodation describes a possible change in land use of areas within a coastal zone. This may dictate a change in agricultural habits, such as converting rice paddies to fish reservoirs, or changes to housing design. Retreat would regulate land use in areas considered to be vulnerable. These basic ideas have since been further developed and are represented in the diagram below.

Developed of the IPCC coastal adaptation strategy, from The Japan Academy (2013)

The latter solution has received recent support from Temmerman and Kirwan (2015), who recommends an ecosystem approach to coastal defence. It highlights the vulnerability of countries situated within vast river deltas, such as Bangkok, Shanghai and New York, to extreme flood events. They say that hard engineering approaches in these environments will become less plausible in the future due to inevitable energy price increases. Additionally, they interrupt natural delta processes, which may actually increase long term flood risk. Instead they propose that ecosystem-based engineering will provide much greater protection, with the restoration and retention of wetland environments enabling further natural land building processes. Projects of this nature have recently begun in Mississippi and the Rhine-Meuse delta. Depending on their success, more countries may look towards implementing this style of long term mitigation strategy.

The Pacific islands are even more vulnerable to rising sea levels and Anote Tong, the President of Kiribati, has recently been voicing his suggestions on how this risk could be managed. As I have mentioned previously, Kiribati are considering the role of migration within their adaptation strategy, but are also determined to maintain the island nation as a habitable entity. In his article, Tong suggests the country relocates to large floating islands, anchored to the sea. These would supposedly be able to support a population of 30,000 for a century. With reference to his slightly unusual idea, he says:

"It's radical, unprecedented, way out of the box, but in the absence of other options, unless you can come up with alternatives, I'm afraid that these are the options available to us."

Whilst this idea is no doubt unique, Tong raises an important point. The conditions we are predicted to face in the next century are unprecedented, and our current methods of adaption and mitigation may be insufficient to deal with this threat. Consequently, there is a constant demand for new and innovative ideas to reduce vulnerability to these threats which could offer a significant investment opportunity to those in the engineering industry.