Poor Form—Comments on the Minneapolis Bridge Collapse

By | August 9, 2007

Indecent twaddle

Apparently, some people know no boundaries for indecency. Take Joseph Romm for instance. Romm, a former member of the Clinton administration, claimed Monday that global warming might have played a factor in the collapse of the I-35W Bridge in Minneapolis last week.

Romm has a new book out called Hell and High Water that describes how global warming is, among other disasters, going to cause massive sea levels to rise in the near future and wreak havoc across the world. And all of it is our (Americans) fault. Here is how the contents are described inside the front cover:

Global warming is the story of the twenty-first century. It is the most serious issue facing the future of humankind, and American energy and environmental policy is driving the whole world down the path of global catastrophe. Hell and High Water is nothing less than a wake-up call to the country. It is a searing critique of American environmental and energy policy and a passionate call to action by a writer with a unique command of the science and politics of climate change.

“Unique command” seems an apt description to say the least. In an apparent effort to drive up book sales, Romm has theorized that the collapse of the Interstate 35 bridge in Minneapolis/St. Paul on August 1, 2007 was caused by global warming. And, further, that if you are not open to that possibility, then you are a global warming “denier.” Here is what he has to say in a blog entry titled “Did Climate Change Contribute To The Minneapolis Bridge Collapse”):
One final point: Some may object to even asking the question, “Did climate change contribute to the Minneapolis bridge collapse?” My guess is those are the same people who deny that global warming is caused by humans or that it is a serious problem — the same people who inevitably say “we can adapt to whatever climate change there is.”

It is one thing to ask the question, it is another to ask the question when the answer is easily identifiable from ample data readily available on the web, and the answer is emphatically no! In that case, asking the question is being alarmist. Ignore the actual data, and full speed ahead with the irresponsible scare stories.
Somehow Romm thinks that the “extreme” heat in Minneapolis on the days leading up to and on the day of collapse may have impaired the structural integrity of the bridge, causing it to collapse AND that the “extreme” heat was caused by global warming, AND that the warming was caused in part by moms driving their kids to soccer practice and piano lessons.

Putting it nicely, this is 100-proof twaddle.

The real “inconvenient truth

Concerning global warming in Minnesota, the figure below shows the historical record of July average temperatures observed in Minneapolis as compiled by the National Climatic Data Center (www.ncdc.noaa.gov). The last point on the graph is July 2007, the first is 1895. There is no overall warming trend in this record. Thus neither “global warming,” nor any other kind of climate change for that matter, is producing an unusual thermal climate in Minneapolis now, compared with the past history. Romm chooses to play past this and other facts.

History of July average temperatures observed at Minneapolis, MN, 1895-2007 (data source: National Climatic Data Center, www.ncdc.noaa.gov).

What about the idea that unusual warmth this July was somehow responsible for the bridge collapse, even in the absence of a warming trend from global warming?

No chance.

Notice that in the graph above, the average temperature this July is unremarkable in the long-term setting, coming in only slightly above (+2.1ºF) the long-term average. Last July (2006), a month when the bridge did not collapse, the average temperature was nearly 4ºF higher than this July.
Maybe extreme daily temperatures were responsible rather than simply a warm month?

No, again.

The graph below (produced from data readily available on-line from the Minnesota State Climatology Office, http://climate.umn.edu/doc/twin_cities/twin_cities.htm) shows the run of daily maximum temperature in Minneapolis from the beginning of July 2007 though the date the bridge collapsed, August 1, 2007. Also shown on the graph (in red) are the temperatures during the same dates back in 1988—another year that the bridge did not collapse. Notice that in 1988, almost every day was warmer than the same day this year. On August 1, 1988, the temperature was 101ºF. On August 1, 2007, the day of the disaster, the temperature was 92ºF. In fact, in 1988, the temperature equaled or exceeded 92ºF for 9 consecutive days surrounding August 1, yet the bridge stood.

July daily maximum temperatures, 2007 (black) and 1988 (red) (data source: Minnesota State Climatology Office, http://climate.umn.edu/doc/twin_cities/twin_cities.htm)
Here is another presentation of daily measurements for Minneapolis-St.Paul during July and early August, again showing that summer temperatures can get extreme.

1 99 1911
2 96 1911
3 100 1949
4 100 1949
5 100 1982
6 104 1936
7 101 1936
8 101 1936
9 99 1976
10 106 1936
11 106 1936
12 106 1936
13 105 1936
14 108 1936
15 102 1988
16 102 1926
17 99 1936
18 101 1940
19 100 1940
20 102 1901
21 105 1934
22 105 1934
23 105 1934
24 104 1941
25 99 1941
26 100 1894
27 104 1931
28 100 1955
29 98 1933
30 100 1933
31 105 1988
1 101 1988
2 99 1988

Daily measurements for Minneapolis-St.Paul during July

Notice that no record highs have been set in recent years (since 1988) for Minneapolis in the days of so-called “catastrophic” global warming. The 1930s and early 1940s dominated the records (19) with a smaller number (4) in the great 1988 heat wave. Minneapolis summers in recent years have shown higher average temperatures due to elevated nighttime readings, characteristic of a growing metropolis with its urban heat island.

This can also be seen with the gradual decline in daily temperature range since the 1960s.

Average daily temperature range (maximum temperature minus minimum temperature) for Minneapolis/St. Paul, averaged by decade.

In a plot of daily maxima for every day since 1960, there is no discernible summer extra-warming. Although with more El Niños in recent decades in the warm Pacific Decadal Oscillation phase, winter maxima were higher in the last decade especially. But that would likely put less stress on the infrastructures not more.

Minneapolis daily maximum temperatures, 1960-2007.

In the weeks prior to the bridge collapse, there was a warm spell but temperatures did not on any day exceed record levels.
In an average summer, 13 days equal or exceed 90F. During the past 10 summers (1997-2006), a total of 48 days have equaled or exceeded the temperature on the day the bridge collapsed. Thus, these kinds of high temperatures are very much the norm in Minneapolis during the summer. And the bridge designers should very well have known this to be the case as there is no lack of temperature data from Minneapolis and the surrounding environs. Daily temperature observations taken in Minneapolis extend back into the late 1800s. And the temperature history is full of hot periods that were both much higher and much longer in extent than anything observed in 2007. For instance, the graph below shows the daily high temperatures during July 1936 alongside those of 2007. While temperatures near the actual date of the bridge collapse were similar in the two years, the data from 1936 illustrate that long periods of extreme high temperature can and do occur in Minneapolis during the summer. In 1936, temperatures equaled or exceeded 95ºF for 13 consecutive days (July 6 – 18), and included a run of 8 out of 9 days above 100ºF, with 6 straight that equaled or exceeded 105ºF. While the I-35 bridge was not constructed until many decades later, the available temperature record clearly showed that temperature can get very hot. Thus, this data should have been incorporated into the bridge design.

July daily maximum temperatures, 2007 (black) and 1936 (red) (data source: Minnesota State Climatology Office, http://climate.umn.edu/doc/twin_cities/twin_cities.htm)


Clearly, the evidence shows that the conditions this summer in the days and weeks leading up to the catastrophic collapse of the I-35 bridge in Minneapolis were by no means out of the ordinary or unexpected.

Neither does the evidence indicate that the summer climate of Minneapolis has been changing significantly over the course of past 100 plus years (since records were compiled) as a result of anthropogenic enhancements to the earth’s greenhouse effect or any other process, either natural on manmade.

As to the bridge collapse and loss of life, if it is determined that the bridge designers, builders and/or maintenance personnel failed to take into account expected weather, then this was a terrible oversight. However, it is difficult to lay fault with either the climate or climate change. Nonetheless, the facts do not deter Joseph Romm from pushing his alarmist agenda and trying to sell books for personal gain on the back of a horrible calamity and personal suffering.

This is simply pushing the limits of poor form too far.

Robert Ferguson, President

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