Hans-Peter Plag October 20, 2014 Foresight: Cumulative Sea Level Equation Vulnerability: The Example of Sea Level Rise
800 Years? 4.5 m 100 Years? How worried should we be? Accepted knowledge in 2000: Greenland: no significant contribution to sea level rise Antarctica: minor contribution Main contribution: steric changes Knowledge in 2014: Greenland: is contributing, is accelerating, potentially a large contribution to sea level rise Antarctica: West Antarctic ice sheet (WAIS) will contribute 4.5 m WAIS Contribution to Global Sea Level
Modified from Church et al. (2010) Example Hampton Roads Soon could get as high as: 20 mm/year (~6 feet/century) Today: 5 mm/year (~1.5 feet/century) Local Sea Level Rise leads to: - more nuisance flooding - higher risk of extreme floods - a transient coast line
Example Hampton Roads Soon could get as high as: 20 mm/year (~6 feet/century) Today: 5 mm/year (~1.5 feet/century) Local Sea Level Rise leads to: - more nuisance flooding - higher risk of extreme floods - a transient coast line INCREASING IMPACTS 20 to 30 years Norfolk: Sea Level exceeding level that causes “nuisance flooding Events per Year Hours per Year “Nuisance Flooding” is very likely getting worse and could become economically damaging Add a rapid sea level rise...
Ecosystem services of coastal ecosystems: $1.6 trillion per year Assume: Local sea level rise of 0.5 m by 2100 Probability 0.8 Results in loss of 20% of current coastal ecosystems Risk is $250 billion per year Loss of coastal ecosystems between 1900 and 2000: 50% 25% in the last two decades
Other changes: - storm patterns - distribution in time - distribution in space
Planning for any limited range of plausible LSL trajectories inherently ignores part of the probability density function of future LSL. How large is the risk associated with the part of the PDF not considered? MOST LIKELY VERY LARGE, BUT WE DON’T HAVE A SOLID ASSESSMENT How likely is it that LSL might by far outside the limited range considered?WE CANNOT EXCLUDE THIS TO HAPPEN IN THE “POST-HOLOCENE” How likely would that turn into a low-probability, high-impact event? MOST LIKELY, THIS WOULD BE A GLOBAL DISASTER AND COULD TURN INTO A X-EVENT