Controls
Primary Controls
Antarctica Controls
Greenland Controls
Info
Introduction
This simulation explores the impact of collapsing polar ice sheets (Greenland and Antarctica) and their impact on global mean sea level rise, along with shrinkage in livable area around the world. Here, we look at US coastal areas, and how shoreline would retreat if Greenland and Antarctica were to dramatically decrease in volume.
Note
This scenario is hypothetical, and by no means fully representative of all the processes involved in both the evolution of polar ice sheets, and the way sea level rises differently in various parts of the world. It does not for example account for local subsidence of the ground, flooding, erosion of the shorelines, glacial isostatic rebound, negative feedbacks from the atmosphere, etc. It is, however, meant to assess the sensitivity of local sea level rise to melting of polar regions.
Datasets Used for the Simulation
- Digital elevation model for US coastal areas: Global Land One-km Base Elevation Project anisotropically interpolated onto unstructured mesh ranging from 500 m to 100 km resolution.
- US overlay: TrueMarble (4km resolution).
Greenland
- Greenland Surface elevation from Bamber et al., 2001.
- Greenland Bedrock elevation from Bamber et al., 2001.
- Other Greenland datasets found at the SeaRISE Present Day Greenland webpage.
Antarctica
- Antarctica Surface elevation from Bamber et al., The Cryosphere, 2009, and Griggs and Bamber, The Cryosphere, 2009.
- Antarctica Bedrock elevation from BEDMAP1+ -> merge of BEDMAP1 (Lythe et al., 2000) and bathymetry grids from Nitsche (LDEO) et al. 2007 and Tara Deen (BAS).
- Other Antarctica datasets found at the SeaRISE Present Day Antarctica webpage.
Model Settings
- Greenland mesh at 20 km resolution split into 3 areas (North, Center and South).
- Antarctica mesh at resolution ranging from 20 to 60 km, split into 4 areas (northwest, northeast, southwest and southeast).
- Computation of SLR using volume above hydrostatic equilibrium and conversion to global mean sea level rise from global ocean surface area. New US coastline computed using simple comparison between surface height and new sea level.
- Code to compute volume above floatation:
function VolumeAboveFloatation(md) {
let vol = 0;
let di = md.materials.rho_ice / md.materials.rho_water;
for (let i = 0; i < md.mesh.numberofvertices; ++i) {
if (md.geometry.base[i] > 0){
vol += (md.geometry.surface[i] - md.geometry.base[i]) * area[i];
} else {
let sh = (di - 1) / di * md.geometry.base[i];
if (md.geometry.surface[i] > sh){
vol += (md.geometry.surface[i] - sh) * area[i];
}
}
}
return vol;
}
// Figure out the new volumes of the polar ice caps
let offset = 0.01;
let vg = VolumeAboveFloatation(mdgre);
let va = VolumeAboveFloatation(mdant);
// Overall volume change
let deltav = (vg - vgi) + (va - vai);
// Overall water equivalent volume change
deltav = deltav * di;
// equivalent slr
// 361 million square kilometers ocean surface
// 10^6 * 10^6 (from etopo)
let newheight = offset - deltav / (361.934 * Math.pow(10,12));
How to Run the Simulation
Remove a certain amount of ice (relative percentage of the overall mass) from Antarctica and/or Greenland using the corresponding sliders (in the "Controls" drawer pane). The ice can be removed from all basins or from a specific basin by using the select menu. The resulting shrinkage of the ice sheets will be displayed in the initial frame, along with shoreline retreat and global mean sea level rise. Specific US coastal areas can be selected using the "Region" select menu.
Note that when viewing this page in portrait orientation, the Antarctica and Greenland panels can be displayed using the Glacier Region buttons after clicking LET'S GO.
Legend
Feedback
If you have any questions or feedback, please send us an email.