According to a new, in-depth analysis

Apr 23, 2010 13:39 GMT  ·  By
Shortest-path tree of Atlanta, the US. An impact of the airport closures before and after closure
   Shortest-path tree of Atlanta, the US. An impact of the airport closures before and after closure

The eruption of the Icelandic volcano Eyjafjallajokull did not only prompt concerns for public health across Europe, but also about the integrity and ability to resist of the global air traffic system. At the peak of the crisis, the massive ash cloud the glaciovolcano released in the atmosphere prompted the closing down of about 27 major European airports, in addition to countless smaller ones. But the impact was global, experts were surprised to learn, with airports in Asia and America forced to shut down as well. A team of scientists from the Northwestern University investigated the full effects.

Things are pretty clear-cut when it comes to Europe. The large ash cloud grounded millions, and took a hefty financial toll on airlines, which lost in excess of one billion euros. But things are not so clear when it comes to the overall, global effects, so the NU team, led by professor Dirk Brockmann, looked more closely into how general mobility patterns were affected at a larger scale. They found severe repercussions in India, Asia and the United States, in places separated from Iceland by other continents, or located very far away.

The group used complex calculations, as well as advanced network theories, to determine the locations that were most affected by the closure of EU airports, but which remained opened at the same time. “We were surprised to discover that at the top of the list were airports outside of Europe, not airports in Europe. Singapore, Hong Kong and Beijing are some of the high-traffic airports most affected, despite being geographically distant from Europe and separated from Iceland by continents,” the team leader says. He conducted the work with Daniel Grady, Christian Thiemann and Olivia Woolley, all of them graduate students at Northwestern, PhysOrg reports.

When looking at the global air transportation network following the eruption, the team noticed that airports such as the one in Madrid, Spain, and Dubai, tended to take on the role of nodes, replacing their crippled European counterparts. “European airports are bridges to the world – the majority of global air traffic goes through Europe. The distances to places have increased globally as a result of the volcanic ash disruption. Mumbai, for example, has become more disconnected than we expected from the US and Africa. Flights from the U.S. to Mumbai normally go through Europe, but now Mumbai is a more distant city to us,” Brockmann adds.

“The removal of those 27 nodes dramatically affects the entire complex system. We can quantify Eyjafjallajökull's effect and illustrate it, which is not a simple thing to do. In this case, the entire air transportation system was slowed but still works. Our calculations show that an actual system breakdown requires the removal of 80 percent of the airports from the system. This shows how robust the system is,” he adds. The expert is based at the university's McCormick School of Engineering and Applied Science, where he is an associate professor of engineering sciences and applied mathematics.