Last year, Nature Geoscience and Science (PDF) published major articles suggesting that the consensus projection for sea-level rise this century was far too low — and could be as high as five feet. Now the Journal of Glaciology joins in with a remarkable analysis, “Intermittent thinning of Jakobshavn Isbræ, West Greenland, since the Little Ice Age” (PDF).
The lead author, Beata Csatho from the University of Buffalo, explains implications of this work for the traditionally very simplified ice sheet models, such as those used by United Nations Intergovernmental Panel on Climate Change (IPCC) to make projections of sea-level rise:
Ice sheet models usually don’t include all the complexity of ice dynamics that can happen in nature. This research will give ice sheet modelers more precise, more detailed data.
If current climate models from the IPCC included data from ice dynamics in Greenland, the sea level rise estimated during this century could be twice as high as what they are currently projecting.
The study “focuses on Jakobshavn Isbræ, Greenland’s fastest moving glacier and its largest, measuring four miles wide.” It documents the behavior of Jakobshavn Isbræ since the late 1800s by combining “field mapping, remote sensing, satellite imaging and the application of digital techniques in order to glean ‘hidden’ data from historic aerial photographs as many as 60 years after they were taken.” It is a very impressive piece of work. (The photo on the right is from 1944 — click to enlarge.)
For the record, five feet of sea-level rise would displace more than 100 million people worldwide — the equivalent of 200 Hurricane Katrinas!