|
|
Several years ago I was manipulating some modern Digital Elevation Models as part of my palaeogeographic work. Part of this involved flooding the modern world for varying sea-level rises, including changes associated with melting increasing amounts of the worlds cryosphere (ice). In the last week the subject of sea-level change has been back in the news as concerns rise again about the effects of global warming on the Arctic and Greenland ice sheets, so I thought that it was time to put some of this work on the web site.
The flooding show in red is not corrected for isostatic effects due to the mass of the water load, nor is there any attempt to correct for thermal expansion due to temparture increases. The results are nonetheless sobering.
|
 |
 |
 |
| Modern sea-level |
Sea-level +c.1m (melting of all modern mountain glaciers) |
Sea-level +c.9m (melting of all modern mountain glaciers + Greenland Ice-sheet) |
|
 |
 |
 |
| Sea-level +c.15m (melting of all modern mountain glaciers + Greenland Ice-sheet + West Antarctic Ice-sheet) |
Sea-level +c.80m (melting of all modern mountain glaciers + Greenland Ice-sheet + West Antarctic Ice-sheet + East Antarctic Ice-sheet) |
Sea-level +c.250m (maximum Cretaceous sea-level high - possibly) |
|
|
LEFT: Detail of the UK and Ireland area with the flooding of all areas below 9m shown in red. It must be emphasized that this is a 'back of the envelope' calculation and what is shown here does not include isostatic effects (either due to glacial unloading, which is still continuing, or the mass of additional water) or changes due to changing sedimentation patterns.
|
|
|
It must be remembered that this is a picture of what might happen and NOT necessarily what will occur in the future. Climate change is complex and there are still many unknowns that further research needs to address, including the potential interaction between climate and anthropogenic land-use changes.
|
| RIGHT: A relief map of the modern world flooded up to about the Cretacous maximum sea-level (as generally interpreted in the published literature). This extreme high (of c.250m abouve present) reflected both the lack of ice sheets on the poles (c.80m sea-level change), but also the volume of the ocean basins and spreading ridges, although this has been disputed. In the Cretaceous, extensive large igneous provinces in the palaeo-Pacific contributed to the displacement of ocean water on to the continents.
|
|
|
