This year on the EGU General Assembly blog there will be guest posts from participants about their research and their impressions of sessions. These are personal points of view not EGU corporate views. If you would like to contribute a research viewpoint, please email us.
This Research Perspective comes from Luís Costa, a PhD student at the Potsdam Institute for Climate Impact Research. He will present his research in NH5.5 Storm Surges and coastal areas: extreme events, damages, and risk.
Lamarck vs Darwin: Evolutionary paths for sea-level rise adaptation
I came across a dilemma when looking on how authors integrate adaptation options to sea-level rise in impact assessment models. Should adaptation at the coastal zones be the product of a Lamarckistic or Darwinistic process? For both ground-breaking naturalists, adaptation was the evolutionary process whereby a population becomes better suited to its habitat, the difference between both conceptions lies on the mechanisms driving changes in the population.
For the last two decades authors have been looking at potential impacts at the coastal zone and proposing adequate adaptation measures to counteract the negative effects of a substantial increase in global sea-levels by the end of this century . Assessments appear to be restricted to a narrow portfolio of adaptation options. Coastal protection, coastal retreat, beach and wetland nourishment rank as the most commonly investigated solutions to adapt to sea-level rise . It appears that most options labelled as coastal adaptation can be better defined as current coastal management practices scaled up to accommodate accelerating levels of sea-level change and highly uncertain storm intensities. In this sense, adaptation to sea-level rise seems to follow a Lamarkistic approach. In the in the same way the giraffe altered its physiology by constantly stretching its neck to adapt to higher trees, researchers seem to envision the upgrade of existing coastal management strategies as a suitable response to higher sea-levels. The same Lamarkistic view is traced to the common assumption that all coastal regions of the world (that are currently in different states of urban and economic development) will rely on the same set of adaptation options within 80 years time. The assumption that technology on coastal protection employed today in developed coasts will be adopted in other world regions is in striking similarity with Lamarck’s claim that the acquisitions or losses wrought by nature on individuals are preserved within the coming generations.
Adaptation to sea-level rise following a Darwinistic approach implies that coastal zones better adapted to sea-level rise survive while the ill adapted ones perish. The idea of a “better adapted” coast demands serious refinement. It is commonly accepted that the European part of the Kingdom of the Netherlands possesses a well adapted coastline. The immense tradition on coastal protection and land reclamation, associated to robust economic performance, seem to provide all necessary conditions for the Dutch to endure sea-level rise. There are even reasons to believe that the inherent vulnerability to sea-level rise of the Dutch culture is socially constructed , highlighting how deep into society adaptation to climate change needs to be considered. Just across the rising Atlantic, the Katrina example warns us for the costly price of developing our coastal activities relying on traditional protective measures. The old New Orleans should have perished, and in its place, a Darwinistic new New Orleans flourish by engaging in a progressive abandonment of traditional protection measures, enforcing a moratorium on coastal development, creating unprecedented liberty margins for the sea and a redistributing its economic activities to safer areas. In the aftermath of the disaster, the rush by the residents to rebuild the familiar and the effort to reconstruct the failed levees to their existing height  places coastal adaptation back in line with Lamarck’s thesis. A Darwinistic view on coastal adaptation seems dramatic. But considering that necessary emissions cuts to avoid dangerous climate change  implies restructuring most of the world’s energetic system, the magnitude of reconfiguring prone coastlines appears to me as an equally plausible challenge.
As a researcher I’m currently struggling with what is the best adaptation approach to sea-level rise. A Lamarck’s adaptation weighted by the technical and economic capacity of coastal communities, or the Darwinistic prospect of a dying coastline as example of a brighter future?
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