Contemporary research indicates that life expectancy at birth has increased by about 47 years in the past three centuries, from about 30 years in 1700 to about 77 years today in OECD countries. In the whole previous history of human kind—about 200,000 years—the increase in life expectancy can have been at most five to ten years, since when life expectancy falls below 20 years, the fertility rate can not be high enough to sustain, let alone increase, the size of the population. (source Center for Population Economics at the University of Chicago). This overall progress in life expectancy indicates that many risks that we used to face from a host of diseases have been defeated.
Of course, risk remains a constant part of daily life. Is urban living becoming more or less “risky” in recent decades in the United States? I see;
1. Fewer fatal plane crashes per mile of flying
2. Lower urban murder rates since the early 1990s
3. Fewer deaths on the job due to industrial accidents or due to military service
4. Much lower levels of urban air pollution reducing health risk
5. Less drunk driving which must translate into fewer traffic fatalities per mile of driving
Many interesting facts concerning modern risk exposure are posted to:
http://hazmat.dot.gov/riskmgmt/riskcompare.htm. The good news is that many of these risk numbers look very small.
A Pessimist would counter that she sees:
1. future terrorist attacks in dense cities
2. more natural disasters in coastal cities caused by climate change
It strikes me that the probability of both of these latter scenarios is very low. A silver lining of Katrina is that evacuations in the face of future storms will be more effectively carried out and the human death toll will be lower.