31 May 2011

Donald Boudreaux: I'll Take That Bet

Writing in the WSJ last week economist Donald Boudreaux of George Mason University offers to make a bet in order to make a point about human-caused climate change in response to Bill McKibben's silly essay from earlier in the week in the Washington Post:
I'll bet $10,000 that the average annual number of Americans killed by tornadoes, floods and hurricanes will fall over the next 20 years. Specifically, I'll bet that the average annual number of Americans killed by these violent weather events from 2011 through 2030 will be lower than it was from 1991 through 2010.
I am willing to take this bet in order to raise awareness of the fact that both sides of the debate over climate change debate can't see the forest for the trees.  The factors that will drive loss of human life due to weather extremes in coming decades will be increasing vulnerability and exposure.

As a condition of the bet, when I win (which unfortunately will occur long before 2030) I ask that the proceeds go directly to the American Red Cross. (Should I lose the bet come 2030, I'll make out a check to the charity of Prof. Boudreaux's choice.)  A second condition is that Prof. Boudreaux agrees to write an op-ed for the WSJ (or some other venue) explaining the bet and why he lost (of course, I am willing to do the same).

Here are the technical terms of the bet that I will accept.  Prof. Boudreaux refers to three hazards: floods, tornadoes and hurricanes.  The dataset that he proposes using is the official record kept by the US National Weather Service (available here in PDF through 2009, and here in PDF for 2010).  This leads to the following summaries for the base period of 1991-2010 proposed by Prof. Boudreaux:

Tornado Flood Hurricane
1991 39 61 19
1992 39 62 27
1993 33 103 2
1994 69 91 9
1995 30 80 17
1996 26 131 37
1997 67 118 1
1998 130 136 9
1999 94 68 19
2000 41 38 0
2001 40 48 24
2002 55 49 53
2003 54 86 14
2004 34 82 34
2005 38 43 1016
2006 67 76 0
2007 81 87 1
2008 126 82 12
2009 21 53 2
2010 45 103 0

1129 1597 1296 4022

In his WSJ column Professor Boudreaux asks his readers to subtract the deaths from Hurricane Katrina because they were the result of a levee break.  It is not clear whether that was just a rhetorical move for the column or if that calculus also extends to the bet. He can clarify that for me in his response. With Katrina the total is 4,022 deaths and without Katrina the total is about 3,000 (again, Prof. Boudreax can tell me which number he prefers).

So far 2011 has seen 518 deaths from tornadoes.  This means that from today through 2030 the United States could see only 3,500 additional extreme weather deaths, or 180 per year (using the higher baseline that includes Katrina deaths, or 154 per year using the lower number of 3,000).  Such numbers would represent an improvement over 1991-2010, and Prof. Boudreax would still lose the bet.  We should be so lucky, and it would take a lot of luck, to see so few deaths due to extreme weather.

The fact of the matter is that our vulnerability to extreme weather is increasing, due to a combination of a growing population and especially urbanization in locations prone to extreme weather events.  This means that even with the hard work by many professionals in a range of fields that has contributed to the dramatic decrease in the number of deaths over recent decades low death totals are unlikely to continue into the future, as this year's tragic tornado season tells us.  Of course, given expected societal trends a reversal in statistics would not necessarily mean that our disaster policies are failing.  What it means is that our responses to extreme weather require constant vigilance, investment and continued hard work.

In trying to score points in the debate over global warming Professor Boudreax misses what really matters most on this issue.  And that is why my response to his question, "Do I have any takers?" is "Yes."

I will email Prof. Boudreaux with this post and update with his response.