Tuesday, December 6, 2016

What Happens to Coastal Cities Vulnerable to Sea Level Rise?

Adapting to rates versus amounts of climate change: a case of adaptation to sea-level rise ( 9 page pdf, Soheil Shayegh, Juan Moreno-Cruz and Ken Caldeira, Environmental Research Letters, Oct. 4, 2016)

Today we review the most immediate aspect of climate change- its impact in terms of sea level rise and how best to adapt to this financially, given that many coastal cities are threatened including London, New York, and Tokyo. The authors consider four scenarios given the current rate of rise of 44 cm/100 years which is expected to increase by almost a factor of ten to 344 cm/100 years as Antarctic ice continues to melt over the next 1,000 years for a 60 m rise in sea level. The scenarios include: taking no action, creating a buffer zone, adapting to change in rise and building dikes to withstand increased sea levels. The optimum distance from the sea for safety increases from 310 m to 481 m as the rate of rise of sea level doubles. Insurance based on static risk need to be revised to a more flexible approach based on rate of rise.

Key Quotes:

“climate is likely to continue changing far into the future. Here, we show how considering rates of change affects the projected optimal adaptation strategy.”

“Recent studies indicate that sea-level may continue to rise for millennia, ultimately leading to up to 60mof sea-level rise” “optimal investment strategies depends on taking into account future rates of sea level rise, as well as social and political constraints….Unrestrained fossil-fuel combustion with release of CO2 to the atmosphere has the potential to ultimately melt all of Antarctica at rates of sea-level rise averaging up to 3 cmyr−1 over the next 1000 years “

“Over the next 1000 years, sea-level is projected to rise at an average rate of 3.44 cm yr−1, if all available fossil fuel resources are combusted and the CO2 released to the atmosphere”

 “In the scenarios where rate of change is taken into account …, the optimal distance from the shoreline for investment increases from 310 to 481m as the rate of sea-level is doubled from 1 to 2 cm yr“

 “Failure to recognize the need for adapting to the rate of climate change undervalues the benefits of early adaptation strategies and increases vulnerability to climate change.”

Flood insurance policies traditionally estimate the likelihood of a flood by assigning a probability to such event. New insurance policies can be designed by taking into account the ongoing rate of sea-level and updating the flood likelihood.”

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