COMPLEX NEGATIVE EVENTS AND THE DIFFUSION OF CRISIS: LESSONS FROM THE 2010 AND 2011 ICELANDIC VOLCANIC ASH CLOUD EVENTS CHARLES F. PARKER Department of Government & Center for Natural Disaster Science (CNDS), Uppsala University, Uppsala, Sweden Parker, C.F., 2015. Complex negative events and the diffu- sion of crisis: Lessons from the 2010 and 2011 Icelandic volcanic ash cloud events. Geografiska Annaler: Series A, Physical Geography, 97, 97–108. doi:10.1111/geoa.12078 ABSTRACT. In a world characterized by complex interde- pendence, crises that originate in one country have the poten- tial to rapidly diffuse across borders and have profound regional and even global impacts. The eruption of the Ice- landic volcano Eyjafjallajökull in April 2010 demonstrates how rapidly a natural disaster can morph from a local crisis with local effects to a cascading crisis with international effects across multiple sectors. After spreading to Europe the ash cloud severely disrupted air travel and paralyzed the European aviation transport system. This cascading crisis caught authorities by surprise and revealed the need to improve crisis preparedness to deal with the threat of vol- canic ash in particular and aviation in general at the interna- tional, EU, and national levels. In the aftermath of the event, reforms and policy changes ensued. Just over a year later, the Icelandic volcano Grímsvötn erupted, providing an opportu- nity to observe the revised system respond to a similar event. The origins, response, reforms, lessons learned, and ques- tions of resilience connected to these complex negative events are the subject of this paper. The article concludes by addressing the question of whether and to what extent the vulnerabilities and problems exposed by the 2010 volcanic ash cloud event are amenable to reform. Key words: cascading crises, transboundary crises, surprise and warning response problems, crisis, crisis management learning and reform, volcanic ash crises, Eyjafjallajökull, Grímsvötn, European aviation system, resilience Introduction In a world characterized by complex interdepend- ence, crises that originate in one country have the potential to rapidly diffuse across borders and have profound regional and even global impacts (Ansell et al. 2010; Galaz et al. 2011; Boin et al. 2013). This means that a volcano eruption in Iceland can ground flights around the world, strand millions of people, and result in huge eco- nomic costs. The ash cloud resulting from the eruption of the Icelandic volcano Eyjafjallajökull in April 2010 caused a massive disruption to air travel and paralyzed the European aviation trans- port system. This cascading crisis caught authori- ties by surprise and revealed the need to improve crisis preparedness to deal with the threat of vol- canic ash in particular and aviation in general at the international, EU, and national levels. In the aftermath of the event, reforms and policy changes ensued. Then, on 21 May, 2011, just over a year later, the new system and reforms were tested by the eruption of the Icelandic volcano Grímsvötn. This second ash cloud event, despite some key differences, nonetheless provided an opportunity to observe the revised system respond to a similar event and make some preliminary judgments concerning the efficacy of the reforms that were implemented. The purpose of this article is to carry out a theo- retically informed qualitative case study, utilizing official documents and secondary sources, to address the following four key objectives: provide an analysis of the origins of the 2010 ash cloud crisis that resulted in the nearly complete shutdown of European air space; examine the crisis manage- ment of the event and how the crisis was resolved; consider the lessons learned and the reforms that followed in the wake of the crisis; and conduct a preliminary assessment of the revised system’s response to the Grímsvötn eruption in May 2011 in an effort to unveil plausible lessons that can help shed light on the prospects of crisis-induced policy change serving as a basis for enhancing resilience. The study of acute policy surprises and complex negative events has tended to disproportionately focus on failures and policy fiascos, such as the September 11, 2001 terrorists attacks, Hurricane © 2014 Swedish Society for Anthropology and Geography DOI:10.1111/geoa.12078 97