Credit: NASA/GSFC, MODIS Rapid Response
During the last two weeks, news of the erupting Icelandic volcano, Eyjafjallajökull, was as inescapable as the volcano’s side effects were for the European airline industry. Beginning on April 15th, Eyjafjallajökull’s pulsed plumes of ash into the sky, and prevailing winds scattered the scouring silicate particles across the continent. The resulting week-long ban on most commercial jet travel throughout northern Europe wreaked havoc around the globe.
Despite protestations from some of the vocal skeptics who also decry other scientifically prescribed preventative interventions against things like swine flu or climate change, the decision to ground flights was clearly the right thing to do. Commercial jets aren’t equipped to detect harmful fluxes of engine-clogging airborne ash, and dynamic weather conditions ensure that the extent and severity of danger zones constantly shift. It’s reasonable to question and perhaps criticize airlines that have failed to better quantify the risks volcanic ash poses to jet engines; it’s not reasonable at all to say that such uncertainty justifies business as usual. If you disagree, I recommend you read this chilling account of a jetliner’s 1982 encounter with an ash plume over the Indian Ocean. The estimated loss of nearly $2 billion due to the grounding pales against the potential damages, financial and otherwise, posed by the risk of passenger-filled planes falling from the sky. Human lives are more tangible than the consensual hallucination that is money.
As people and products failed to reach their final destinations amid the atmospheric turmoil, remarkable ingenuity emerged. In the struggle to get from point A to point B, businesses plotted new routes for delivering goods, while many individuals turned to slower travel methods like rail, automobile, boat, horseback, and even their own two feet. A newfound excess of time spurred creativity: TED organized an impromptu conference in London, and plans were made for a magazine produced solely by stranded travelers. The International Civil Aviation Organization used Smithsonian Institution data to correlate the world’s active volcanoes against major flight paths, and a platform debuted for using such data to make testable predictions of when and where the next disruptive eruption could happen. Some thinkers wrote that the crisis foretold a future era where planes were only encountered as relics in museums and air travel regained its sense of miraculous wonder; others saw an opportunity to engage the public on the finer points of volcanism or risk management. All across Europe, people paused to savor the simple pleasure of a clear blue sky suddenly freed of contrails.
For me, the past week’s events resonated most strongly with a study from Sergey Buldyrev and colleagues that was published in Nature the day before Eyjafjallajökull’s eruption. The researchers investigated catastrophic failures in complex networked systems—systems like the closely coupled infrastructures underlying modern transportation, electricity distribution, telecommunications, and financial transactions. These systems are constructed from many interdependent nodes, which gives them greater stability and resilience: If one node fails, material, money, energy, or people are routed through other nodes, and functionality is maintained. But past a certain critical threshold of node failures, the system fragments and cannot function.
Buldyrev’s team modeled how disruptions percolate through a tightly linked pair of idealized interdependent networks, and found a counter-intuitive result: The failure of even a small number of nodes in one network can cause additional failures in the second. These failures can then feed back into the first network and cause yet more node failures. In other words, the greatest strength of an interdependent network in isolation is also the greatest weakness of interdependent networks as a whole. Two closely linked, highly resilient systems can suffer catastrophic failure through initially small disruptions that would have been essentially harmless to either network individually. What’s true for two linked networks presumably holds for larger assemblages.
Which brings us back to Eyjafjallajökull. Like all of Iceland’s volcanoes, this one is fueled by the tectonic spreading of the Atlantic seafloor and a “hotspot” of upwelling material from the Earth’s deep interior. This confluence of geology has caused periodic eruptions for more than ten thousand years; on human timescales, there’s nothing new about it. On the other hand, only in the last half-century has flinging winged tubes of steel and aluminum through the air become a common method of high-speed transportation. Mix this development with increasingly powerful and ubiquitous information technology and telecommunications networks, stir, and at a stroke all is transformed. The interdependent biological, technological, and cultural systems of the planet now freely mingle and tightly meld in a globalized milieu, with surprising effects. Leaving its volcanic ash aside, just the pronunciation of Eyjafjallajökull’s Icelandic name placed international news organizations into momentary disarray. In a merging world, nothing is too trivial to gain significance through disruption.
Given this week’s geophysical unrest, it’s fitting that yesterday marked the fortieth anniversary of Earth Day, an annual holiday meant to foster appreciation for the planetary environment. The holiday’s a worthy idea, but only when stripped of its “save the planet” sensibilities. A better message for Earth Day would be more frightening, and closer to the truth: save the humans. The planet will endure our collective ravages and the biosphere will eventually rebound. The world has certainly changed over the past forty years, but we have changed even more. As the products of countless interdependent complex systems, we seem to somehow harbor their flaws. Now, we’re making them manifest, eliminating the interstices that used to protect and insulate the thin veneer of life that glosses this planet. Our greatest strength has become our greatest weakness; we are complex, but fragile. Our systems are connecting, with each node at our fingertips. Alas, if only their failures could teach us to fly.
Lee Billings is a staff editor for Seed. He likes space.
Originally published April 23, 2010