Posts Tagged ‘sea level rise’

assessing sea level rise using geographic information systems

Tuesday, December 8th, 2009

Increased attention is given to environmental issues at the meeting of the United Nations Climate Change Conference in Copenhagen. As carbon dioxide and other greenhouse gases are released into the atmosphere due to anthropologenic activities, more and more solar radiation gets trapped inside Earth’s atmosphere, increasing the average temperature. This had a direct impact on continental glaciers as well as alpine glaciers, causing them to melt and flow into the oceans. A large part of Earth’s freshwater (about 70%) is stored in glaciers, which is why their melting has the potential to increase sea levels of several meters. This rise can cause many problems for people living on islands or in coastal regions. As water rises, part of land will be completely submerged and others will get severely eroded due to the increase in wave energy and increased storm magnitudes. Expensive operations like community relocation or community protection will have to be put in place in order to avoid human losses. To be able to assess the need for action, several methods have been developed, using GIS.

Scientists at the University of Kansas have developed a technique for analysing the internal structure of glacial ice, which will then help them assess the status of the glacier. When more ice melts from the glacier than is accumulated due to precipitation, the glacier shrinks. This is the current state of most of he world’s glaciers. Although they have rates of decrease that seem insignificant at a human time scale, these rates are very fast when analysed at a geological time scale. By looking at glacial profiles using radar, not ice cores, the analysis becomes less time-consuming and data easier to gather although the costs may be higher.

In Australia, GIS is incorporated in a climate model to allow for the fast first analysis of impacts of sea level rise at the scale of a beach. This method is cost-effective as it does not involve expensive aerial photography on a range of years. It allows a management committee to have an overview of the upcoming situation without spending large amounts of money that could be better invested in damage control.

For the general public, a Google Maps application has been developed to visualize sea level rise. Users can choose three values of sea level rise, each of which corresponds to a colour. When the user runs the app, a series of coloured dots appear on the landmasses displayed on Google Maps. The use of this app requires no computing skills and is very fast. It is perfect for educational purposes or for aspiring environmentalists, although it is insufficiently accurate to use for spatial analysis that would eventually lead to decision making.

thanks to CA, Intro to GIS, for the post.