Saturday, September 27, 2014

Climate Change Workshop, part 3.

Monica Deming of the Oklahoma Climatological Survey was our next presenter at the Climate Change workshop. We notice extreme events, such as Oklahoma having a winter temperature of 27 F below zero in winter 2011 (near Nowata) but the next summer, 20121, was the hottest summer on record in Oklahoma or for any state ever. We can be fairly confident that global warming will bring more extreme events. As I wrote in my book Green Planet: How Plants Keep the Earth Alive (still available!), global warming is "stirring the climate pot more vigorously." I'm no expert but I hope this metaphor is useful.

Then Monica explained the basics of global warming and the Milankovitch cycle. Danny Mattox then acted it out--the first time I have ever seen anyone attempt this! He played the Earth, revolving around Monica (the sun) at various tilts and distances.

Monica summarized the latest conclusions of the IPCC, including their most current projections. There are about 25,000 indicators that Earth is becoming warmer, everything from thermal expansion of ocean waters to melting ice to direct temperature measurements. She gave us more information about these measurements, e.g. that Arctic sea ice as melted much faster even than scientists had recently predicted. Unfortunately, the world is continuing on the path of the maximum predicted warming. At this rate, the heat wave of 2012 will not just seem normal, but seem cool, by 2090. Yes, it got up to 120 F in parts of Oklahoma in 1936, but the scientific projections are that the number of summer days exceeding 100 F each year will increase, to perhaps 120 days a year by the end of the century.

And now for something different. Instead of listening to talking heads, no matter how interesting they are, the participants will get on computers and actually work with climatological data, under the guidance of Brad Illston, a research associate at Oklahoma Mesonet, a service provided by the Oklahoma Climatological Survey. This is one of the finest repositories of meteorological information in the country. No other state, as far as I know, has as much data so easily accessible in such a visual format.

Mark Twain referred to "lies, damned lies, and statistics." Statistics can be abused. Brad explained how to use them honestly. But even when used honestly, statistics can be misleading. Averages can be misleading, even if honest. I recall hearing of an old Kansas farmer who said, "In fifty years of farming, I've only seen two average years." So it helps to use not just averages but also some estimate of variability as the standard deviation. If most of the years had been close to average, that Kansas farmer would have seen a small standard deviation. Oklahoma City and San Diego have the same average annual temperature, but the temperatures in OKC are much more variable, a fact constantly confirmed by exchanges of text messages between me and my La Jolla sister. A storm passed through San Diego last week, and my sister texted me, the storm uprooted a tree! But this sounds like an ordinary summer day in Oklahoma.

Another example of being confused by statistics is, what do we mean by a hundred-year flood? It means that, every year, there is a one percent chance of it occurring. It does not mean such floods occur every hundred years, on the dot. As it turns out, the odds of at least one such flood occurring in 100 years is not 100 percent, but 63.4 percent.

The participants then went to the computers to access and use some real Mesonet data. The data are very user-friendly. You can easily graph annual changes in temperature for any year, or for many years on the same graph. Just by looking at the graph, you can see that winter is the season that has the most year-to-year variability (or even day-to-day variability) in Oklahoma. Also, you can access a beautiful color map that indicates soil moisture in August 2011, during a severe drought. Not all of Oklahoma was experiencing a drought; you can see which areas were very dry compared to a long-term average (in red) or wetter than normal (in green). The map is mostly red, but there are green spots. The Oklahoma Mesonet therefore not only makes available a great deal of data in a very organized fashion, but you can construct almost any graph that you might want.

It occurred to me that weather disasters can also test our altruism. If every community along a river builds levees, in an understandable desire to protect their own properties, then there will be a much greater volume of water running downstream, vastly increasing the risk that downstream levees will be overtopped or destroyed.

I would like to end with the same book recommendation I made last year. The Control of Nature by John McPhee documents three examples of hubris, in which we humans think we can control nature. One of the examples is how we are trying to force the Mississippi River to stay in its present channel, even while we are creating conditions that will ultimately cause it to jump its banks and create a new delta.

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