Sea level and flood projections

We followed the Intergovernmental Panel on Climate Change's (IPCC) Fifth Assessment Report (AR5) projected global sea-level rise by 2100, forced by different GHG emission scenarios²⁹. Projected rise of sea level under each scenario is based on the addition of specific forces including steric changes, melting of glaciers and ice caps, the Greenland Ice Sheet, the Antarctic Ice Sheet, and land water storage¹². Sea level projections in Cartagena for 2050 and 2100 were obtained from the Integrated Climate Data Center of the University of Hamburg (ICDC, http://icdc.cen.uni-hamburg.de/1/daten/ocean/ar5-slr.html).

We used two GHG scenarios (RCP) from moderate (RCP 4.5) to unmitigated growth of emissions (RCP 8.5). The data consist of gridded fields of projected sea-level change estimated as the 20-yr mean differences between the 2081–2100 and the 1986–2005 periods, with a horizontal resolution of 1°. The RCP 4.5 and RCP 8.5 scenarios were assessed for the Cartagena region from data produced by the ICDC-University of Hamburg (Fig. 5). Also, we used a new digital elevation model, CoastalDEM, produced by Climate Central that uses neural networks to reduce the error of elevation data. This worldwide CoastalDEM shows that many of the world’s coastlines, including the Caribbean and Cartagena region (Fig. 5), are situated far lower in elevation than previously known from past DEMs^22,32.