Catastrophe

Worldwide, cities face increasing risk of catastrophes. The Indian Ocean tsunami of 2004, with more than 240,000 deaths, and Hurricane Katrina of 2005, considered the most costly disaster in U.S. history at over $200 billion, captured world attention. Most of these losses were sustained in urban areas with high concentrations of people and property located in extremely low-lying hazardous areas. These devastating events are likely precursors to more frequent and severe catastrophes to strike cities in the foreseeable future.

Catastrophic events can be conceptualized according to their source. Some events result from largely uncontrollable forces of nature such as earthquakes, hurricanes, and tsunamis. Other events are caused by combinations of natural forces and human action. For example, dredging and filling in wetlands for urban development often results in loss of the capacity of watersheds to store stormwater runoff, which increases the risk of flooding for downstream communities. Still other catastrophes result from deliberate human will like terrorism, arson, and armed conflicts.

Catastrophic events can be slow-onset, multi-episodic events or rapid-onset, single episodic events. Slow-onset catastrophes result from clusters of traumatic episodes (e.g., protracted drought due to long-term absence of precipitation, large-scale abandonment of inner cities due to prolonged divestment in built environments or recurring crime). Rapid-onset events include terrorist attack, hurricane landfall, and earthquakes.

Catastrophes need to be distinguished from disasters when considering the rising global environmental risk to cities. Both catastrophe and disaster refer to crisis events of sufficient enormity to cause disruption to infrastructure (sewer, water, electricity, and roads), local economies, housing, and everyday functioning of cities. Yet, a clear distinction exists between them that must be understood when assessing the risk to cities. Several dimensions of these crises help us to make the distinction. First, there is the scale of destruction. Most or all of a city's built environment is heavily impacted in a catastrophe, but only partial destruction occurs in a disaster. The damage in New Orleans from Hurricane Katrina was catastrophic, as 80 percent of the city was flooded. The 1902 volcanic eruption of Mount Pelée buried the entire city of St. Pierre on the island of Martinique in the Caribbean. Nearly 30,000 residents perished, and only one man survived: a prisoner in solitary confinement. In contrast, disasters strike only parts of a city. The Mexico City earthquake of 1985, considered a major disaster, caused destruction of only 2 percent of the residential housing stock. The damage caused by the attack on the World Trade Center on September 11, 2001, was confined to only a few city blocks in lower Manhattan.

Second, there is the degree of accessibility of aid. Aid for emergency response and recovery is much more problematic in a catastrophe compared to a disaster. An entire region of communities is devastated and unable to contribute to the need for personnel, supplies, and communication. In a disaster there is usually only one major target for the convergence of assistance, but in a catastrophe many nearby localities are targets and often compete to gain the attention of external aid donors. After Katrina, the devastated cities in southern Mississippi (Biloxi, Gulfport, Pass Christian) could have anticipated a flow of assistance from the major metropolitan city, New Orleans, but the catastrophic conditions throughout the region precluded this possibility.

...