Several of my students claim the storm and flooding in Arizona this week are proof of climate change caused by humans. I've had to explain why this is not true.I lived in Phoenix. I’ve even used an Arizona flash flood in one of my novels. But people only believe what they’ve experienced in their own lifetimes (well, the media did claim that this is a once in 200 year storm).
http://www.wfmynews2.com/story/news/nation/2014/09/08/arizona-flash-flooding-turns-highways-into-rivers/15291219/
So we have 200-year storms a few times each century. Brilliant reporting!
Actually, these floods supposedly occur once in a thousand years:
Chandler, Arizona, received 5.63 inches of rain, which had less than a 0.001% chance of occurring in any given year, according to NOAA's precipitation frequency data — a once-in-1,000-years rainfall event.... According to the National Oceanic and Atmospheric Administration's (NOAA) estimates, this amount of rain within a six-hour period has just a 0.002% chance of occurring in any given year. Another way of saying this is that it is about a once-in-200-years precipitation event, although these statistics can be misleading, since records only go back to the late 19th century.
http://mashable.com/2014/09/09/arizona-nevada-deadly-rains/
At least they recognize the statistics "can be misleading" here, but in what sense can they not be misleading?
In reality, Phoenix is subject to periodic flash floods every 5 to 10 years. Some are worse than others, of course. Here are some photos from prior ones. Note that these dates were in years when atmospheric CO2 was much lower than it is now.
In 1914, the flood filled the river. Here is the Ash Avenue Bridge, with Tempe Butte in the background.
The 1980 flood washed out every bridge except for the Mill Avenue Bridge.
The 1993 flood washed out bridges that had been rebuilt.
The 1966 flood did a nice job on infrastructure, too.
No comments:
Post a Comment