ACCELERATING SEA-LEVEL RISE – PROJECTIONS AND IMPLICATIONS

Accelerating greenhouse gas buildup, ice sheet melt, summer Arctic pack ice thinning, and Arctic tundra and methane hydrate melt all point to accelerating sea level rise through this century. Combined ocean w arming and expansion, glacier melt, and ice sheet melt should produce at least 150-180cm sea level rise this century. This will result in abandonment of all sandy barrier islands, inundation of significant portions of the world’s major deltas, and force nearly complete relocation away from low lying coastal areas. If this accelerated sea level rise has reached 150cm at the end of the century, sea level will be rising at 30cm per decade and accelerating. The world’s port facilities and any remaining coastal infrastructure will need to be adapted to a rapidly shifting coastline.

In addition, the anticipated accelerated warming and ice melt leads to the significant probability that collapse of one or more ice sheet sectors will cause one or more very rapid pulses of sea level rise of 1-10m. This happened repeatedly as climate and sea level moved from the last ice age to the present interglacial, and must be expected over the next few centuries because of severely and destabilized polar zones. Biological and cultural assets too valuable to lose (e.g. seed banks, Library of Congress, unique coherent cultural hubs) or too critical to be inundated or disrupted (e.g. nuclear power and waste disposal sites, critical military and transportation centers, agricultural centers) should be moved well above the reach of any possible major sea level rise pulses. The authors suggest above 52m elevation.