capture of CIRES logo with CU and NOAADanger from the sea - Sea-level rise in a changing climate

Dr. John J. Clague, Emeritus Professor at Simon Fraser University

Friday November 3, 3 pm, at CIRES Auditorium, room 338

Abstract: The rise in ocean levels is among the most dangerous of the many secondary effects of near-future climate warming. On a global scale, sea level is currently rising at an average rate of about 3.5 mm/yr; this rate is nearly 50% higher than rates during the first half of the past century. Sea-level rise has been driven by a nearly 1oC rise in average Earth surface temperature since the early 1900s and, more specifically, has resulted from the loss of alpine glacier ice cover and thermal expansion of ocean waters. A further minimum 1oC rise in average global temperature is ‘locked in’, perhaps before the middle of this century. Continuing warming will ensure that the sea surface will continue to rise, likely reaching an average level nearly 1 m higher than today by the end of the century. This rate of sea-level rise is without precedent in the Holocene and matches some of the highest rates of the Pleistocene Epoch.

Recently, a group of respected climate scientists argued that IPCC has underestimated the amount of sea-level rise by the end of this century due to as yet poorly understood contributions of water from Greenland and Antarctica. Uncertainties in future rates and magnitudes of sea-level rise stem largely from two sources – future anthropogenic carbon emissions and poor knowledge of how rapidly Earth’s cryosphere will equilibrate to the warmer climate we face. Projected costs of protecting existing low-lying coastal infrastructure from higher seas could amount to hundreds of trillions of dollars. However, even with a massive effort, traditional engineering measures, mainly sea dykes, will be effective only for 1-2 m of sea-level rise. Displacement of hundreds of millions of people from low-lying coastal areas, with attendant social disruption and strife, will accompany sea-level rise more than 2 m.

More about Dr. Clague and the event here.