Using computer simulations, climatologists at NASA have estimated how the location of a melting glacier affects sea level rise in the largest port cities across the globe. In a paper published in Science Advances, the scientists showed which glaciers melting will have the greatest effect on a particular city. On the website of NASA is available and interactive map of glaciers, which can be used to estimate the sea level rise in 293 port cities in ten, a hundred or a thousand years, and find out what glacier will contribute most to this increase.
One consequence of the steady rise in the Earth’s temperature in recent years is the steady rise in sea level. In the 20th century alone, the average global sea level has risen by 17 centimeters. The main reason for this is the melting of glaciers, both in the largest ice sheets: the Antarctic and Greenland – and smaller mountain glaciers and ice formations on the water surface. Because of this, by 2100, the average sea level may rise by as much as 15 centimeters to 2 meters. However, due to the rotation of the Earth and uneven distribution of gravity sea level is also rising unevenly. In this case, reliable ways to predict how the local sea level in specific cities located on the coasts of different continents, to date has not been proposed.
American climatologists from NASA led by Eric Larour (Eric Larour) have decided to study the sensitivity of port cities around the Earth to the melting of specific areas of ice sheets and other ice formations. To do this, the authors of the work proposed a method based on a joint computer simulation of the circulation of the atmosphere and water in the world’s oceans, taking into account the rotation of the earth and the uneven distribution of gravity. These data were used by scientists for a mathematical model that links local sea level rise with local changes in the thickness of the glacier. The proposed algorithm allowed to take into account not only the contribution from melting glacier, but also the processes occurring as a result of warming and melting in the ocean: water expansion and changes in the directions of ocean currents.
The areas of the Greenland ice sheet whose melting would cause the greatest sea level rise in the nine major port cities on Earth
In total, the authors of the work evaluated the sensitivity to melting of the various glaciers of sea level in 293 port cities. It turned out, for example, that water levels in London are most affected by melting of the western part of the Greenland Ice Sheet, and in New York – by melting glaciers in its northeastern part. In this case, each year the sea level in New York should rise by a quarter of a centimeter, and in two hundred years, as a result of melting glaciers, it will rise by about half a meter.
According to scientists, their proposed model can be easily changed later, taking into account future climate changes.
It is worth noting that the assessment of sea level rise as a result of melting glaciers is important not only for large cities located on the coasts, but also for less populated areas, where important objects for mankind are located. For example, after the abnormally warm year of 2016, it was the melting of the permafrost that led to a small flood in the World Seed Vault located on Svalbard Island.