In spite of the very real threat of terrorism, I believe that our greatest threats are from other sources. To gain some perspective, let's compare the impact of several major events:

  1.  Hurricane Katrina: The official death toll now stands at 1,163 and the damage higher than $200 billion, topping Hurricane Andrew as the most expensive natural disaster in U.S. history. Over a million people were displaced - a humanitarian crisis on a scale unseen in the U.S. since the Great Depression.
  2.  Spanish Flu epidemic of 1918: 675,000 American fatalities and estimates of 21 to 50 million fatalities worldwide, in a single year. By comparison, WWI killed 9 million men over a 4-year period. Recent analysis of 80-year-old specimens preserved in wax indicates that this flu virus originated as a bird virus that mutated into a swine virus that mutated into a human virus.
  3.  Destruction of the World Trade Center (9/11/2001): Estimated fatalities of 2,936. Insured property damage to the World Trade Center and the Pentagon is estimated at a combined total of $19 billion dollars.
  4.  Indian Ocean Tsunami (12/26/2004, Sumatra-Andaman earthquake): One of the most deadly natural disasters in modern history, the United Nations estimated 229,866 dead or missing people.  The earthquake that caused the tsunami has been estimated at 9.1-9.3 on the Richter scale, making it the fourth largest quake since 1900. Over 1.7 million people were displaced and property damage has been estimated at rebuild costs of over $15 billion (relatively low due to damage in mostly 3rd world locations).
  5.  Hurricane Andrew (8/24/1992, Florida): 65 fatalities, 600,000 homes and businesses destroyed or badly damaged. Property damage estimated at $26 billion.
  6.  Hurricane Mitch (Oct./ Nov. 1998, Central America): Over 22,000 fatalities, leaving 3,000,000 homeless, Mitch was the 4th most intense Atlantic hurricane of this century. There is speculation that global warming contributed to Mitch's severity and unusually long duration (it stalled over Central America for almost one week). Property damage was estimated at $8.5 billion (relatively low figure due to third world location, but higher than the GDP of Honduras and Nicaragua).
  7.  Bubonic Plague (China and Europe, 6th, 14th, and 17th centuries): An outbreak in China was spread to Italy in 1347. Over the next 5 years, it spread throughout Europe, killing about 25 million people, roughly one third of Europe's population at the time. The cities became death traps and were deserted until the plague subsided.
  8.  Kobe Japan Earthquake (6.9 magnitude, 1/17/1995): 5,470 fatalities, 33,000 injured, 300,000 people left homeless, and an estimated $200 billion in damages (4% of Japan's GDP). Nearly tied with Hurricane Katrina as the most costly natural disasters on record.
  9.  China's Yangtze River Flood (summer 1998): 3656 fatalities, 33,000 injured, 14 million people left homeless (an astounding figure!!), 223 million affected, and over $20 billion in damages. Severe deforestation (85%) of the Yangtze River watershed has been blamed for significantly contributing to the flood's severity, by reducing the land's capacity to absorb excessive rainfall.
  10.  Bangladesh Cyclone (1991): Killing at least 138,000 people and leaving as many as 10 million homeless, the 1991 Bangladesh Cyclone ranks as one of the deadliest tropical cyclones on record.
  11.  Shansi China Earthquake (unknown magnitude, 1/23/1956): Fatalities estimated at 830,000 people.

Except for possibly biological or nuclear terrorism, from a review the above statistics one may conclude that natural disasters, such as storms (growing more severe due to global warming), earthquakes, and plagues, far out rank terrorism in scope.