While many industries have seen negative financial, regulatory and human knock-on effects from climate change, one industry has thrived: the climate change impact mitigation industry.
Rising seas have proved a particular challenge for cities on or near the water-edge, yet dams have remained the ubiquitous mitigant with little successful innovation over time. This post explores the business case for re-focusing industry efforts from innovation to improving defense resilience.
The Sinking ‘Floating City’
Venice is supported by more than 10 million multi-century-old wooden poles which hold up the foundations of its buildings.[i] These poles rest on a layer of hard clay and are sinking into the clay at a modest rate of ~2mm/annum.[ii] More worryingly, sea-level rates are projected to rise by ~8.6mm/annum through 2100.[iii]
To combat this, the Italian government has commissioned MOSE (translation: Experimental Electromechanical Module), a series of 78 barriers that will rise from the sea, blocking high waters from entering the lagoon’s three entrances.[iv] One lagoon will include a lock, to facilitate trade continuity.
Consorzio Venezia Nuova (CVN) is the pass-through company comprising the for-profit research, design and execution Italian-only companies responsible for MOSE.
Designing MOSE: Promoting Versatility
Traditional tide-mitigation barriers have focused on blocking an entire river-way or lagoon entrance(s), e.g., London’s Thames Barrier. However, this strategy presents a challenge for Venice, which as a historically important Freeport still accepts ~4,800 passengers arriving by cruise-ship per day:[v] how can you facilitate substantial sea trade while blocking increasingly frequent sea threats?
Slated for completion in 2018, MOSE is intended to strike this delicate balance, since the 78 barriers across lagoon entrances can be variously blocked, partially blocked or unblocked as befits the needs of incoming ships. Importantly, deep and wide cruise ships are accommodated since the barriers can be brought to the bottom of the lagoon inlets.[vi]
Designing MOSE: Sacrificing Resilience
This new and innovative solution is not without downsides. MOSE is designed to protect the city from seas of up to 286cm above current levels.[vii] The project was approved in 2003 using then-current forecasts, and unfortunately, the following decade has seen a doubling of estimations of the rise in sea-levels by 2100.[viii] Some expectations reach ~3-4x the annual rise vs. expectations just two decades ago.[ix]
At current average sea levels, a tide of 57cm leaves 2% of the city surface submerged, while 77cm (the intended threshold for raising the barriers) swallows 12%, and 135cm covers 80%.[x] The last fifty years have seen eight events of 80%+ surface-level submersion, with a max height above average of 194cm, and an average tide of 157cm.[xi]
Assuming a catastrophic event of 194cm-above-average tides and an increase in average sea levels of ~8.6mm/annum, MOSE’s protection period is ~105 years, roughly the intended usage timeframe at time of project authorization.[xii] Assuming sea increases of 13-14mm/annum shortens effectiveness to ~60-70 years.
Furthermore, since the infrastructure’s resting state is submerged, maintenance is more complex vs. above-water structures. Since rising sea levels correspond to a lower threshold for the MOSE operators to trigger the barriers, usage and maintenance requirements should increase. Performing maintenance on submerged structures is a key negative factor of MOSE, and current projections of sea level rises and subsequent barrier usage exceed what the structures were designed to be able to withstand.[xiii]
Next Steps for CVN’s Constituents
When considering sea-level assumptions and maintenance difficulties, many scientists now believe that MOSE’s effective use period will be limited to decades.[xiv] [xv] Likely as a consequence, MOSE Project has since been expanded to include non-barrier-based elements such as raising the height of Venice’s quaysides. The project’s extension has been branded “Not Just MOSE.”[xvi] In part due to these extensions, costs have escalated from ~€4.1bn to ~€5.5bn.[xvii] [xviii]
My recommendation for CVN’s constituents is to acknowledge the deficiency in planning for versatility vs. resilience. When considering future projects, planning for resilience must be the primary objective, with all local elements and commercial biases taking a back seat. This may be a short-term negative for many involved—more expensive structures lead to higher government costs and local taxes, while lower design flexibility leads to less competitive differentiation between construction companies. However, the MOSE Project clearly exhibits the pitfalls of overlooking a primary objective for the sake of a secondary objective; it would be ill-advised to repeat this process.
[i] Eric Nakasako, Illumin, vol. X, no. IV (July 2008), http://illumin.usc.edu/130/a-look-at-venice-past-and-present/, accessed November 3, 2016.
[ii] Science Channel, “Sinking City—Venice,” http://www.sciencechannel.com/tv-shows/strip-the-city/videos/surprising-structure-holding-venice-up-from-beneath-the-ground/, accessed October 31, 2016.
[iii] US Department of Commerce National Ocean Service, “Is sea level rising?” http://oceanservice.noaa.gov/facts/sealevel.html, accessed November 2, 2016.
[iv] MOSE Project, “MOSE System,” https://www.mosevenezia.eu/?lang=en, accessed November 1, 2016.
[v] Port of Venice, “Passengers,” https://www.port.venice.it/en/passengers.html, accessed November 3, 2016.
[vi] MOSE Project, “MOSE System”.
[vii] MOSE Project, “MOSE System”. 286cm at current levels = 300cm at 2003 levels.
[viii] US Department of Commerce, “Is sea level rising?”
[ix] Center for American Progress Action Fund/Think Progress, “Has The Rate Of Sea Level Rise Tripled Since 2011?” https://thinkprogress.org/has-the-rate-of-sea-level-rise-tripled-since-2011-27a9ebd7a130#.p7yxzjss5, accessed November 2, 2016.
[x] City of Venice, “The altimetry of the historical center: percentage of flooding,” http://www.comune.venezia.it/archivio/1754, accessed November 3, 2016.
[xi] City of Venice, “Data & Statistics,” http://www.comune.venezia.it/archivio/3045, accessed November 3, 2016.
[xii] City of Venice, “Venice Altimetry,” http://archive.comune.venezia.it/flex/cm/pages/ServeAttachment.php/L/IT/D/a%252Fa%252F0%252FD.7b6da843719cced7726d/P/BLOB%3AID%3D1754/E/pdf, accessed November 3, 2016.
[xiii] City of Venice, “Venice Altimetry.”
[xiv] World Bank, “Climate Resilient Cities,” http://siteresources.worldbank.org/INTEAPREGTOPURBDEV/Resources/573631-1233613121646/venice_extop.pdf, accessed November 3, 2016.
[xv] Steve Connor, “Venice flood barriers scheme ‘will soon be obsolete,’” http://www.independent.co.uk/news/world/europe/venice-flood-barriers-scheme-will-soon-be-obsolete-9263236.html, accessed November 2, 2016.
[xvi] MOSE Project, “Not Just MOSE,” https://www.mosevenezia.eu/not-just-mose/?lang=en, accessed November 1, 2016.
[xvii] MOSE Project, “MOSE System.”
[xviii] IlFattoQuotidiano, “[trans.] MOSE, in ten years, costs [€]1.3 billion more,” http://www.ilfattoquotidiano.it/2014/06/06/mose-in-dieci-anni-13miliardi-di-costi-in-piu-e-allarmi-inascoltati/1015136/, accessed November 1, 2016.
[xix] Photograph credit: MOSE Project, “MOSE System.”