Wednesday, 8 February 2012

Global Warming through the eyes of a True Believer

I was looking for something totally unrelated to global warming, climate change, blind meteorologists etc., when I stumbled upon "Golden State Heating Up, Study Finds" from 2007 on PhysOrg - not a site I've ever spent any time on in the past. I have seen a few links on Google News, but the brief summaries usually put me off - the site seems to be the haunt of dyed-in-the-wool believers in "settled science".
Average temperatures in California rose almost one degree Celsius (nearly two degrees Fahrenheit) during the second half of the 20th century, with urban areas blazing the way to warmer conditions, according to a new study by scientists at NASA and California State University, Los Angeles.
Of course, those who don't acknowledge the significance of the Urban Heat Island (UHI) effect wouldn't see the irony in that "urban areas blazing the way to warmer conditions".
The scientists found great variations in temperature patterns throughout the state. Average temperatures increased significantly in nearly 54 percent of the stations studied, with human-produced changes in land use seen as the most likely cause. The largest temperature increases were seen in the state's urban areas, led by Southern California and the San Francisco Bay area, particularly for minimum temperatures. Minimum temperatures at some agricultural sites showed increases comparable to some urban areas. Rural, non-agricultural regions warmed the least. The Central Valley warmed slowest, while coastal areas warmed faster, and the southeast desert warmed fastest.
Note "particularly for minimum temperatures" and "Rural, non-agricultural regions warmed the least" - the signature of UHI. No mention of that here, of course.

The paper (no title nor date mentioned - very useful) would seem to be LaDochy, S., R. Medina, W. Patzert (2007): Recent climate variability in California: Spatial and temporal variations in temperature trends, Climate Research CR 33:159–169. The trio seem to be unaware of UHI - in fact in their paper they say (thanks, CO2 Science)
"the small increases seen in rural stations can be an estimate of this general warming pattern over land," which implies that "larger increases," such as those found in areas of intensive urbanization, "must then be due to local or regional surface changes."
However, the thrust of this post is not directed at Medina, but at the original NASA/JPL author of the article, for below my last quote from that is this graphic:

In Los Angeles, average annual temperatures have increased steadily over the past 130 years. Image credit: NASA/JPL/Cal State L.A.
Notice "increased steadily over the past 130 years". The author clearly is looking at the chart with the eyes of a "True Believer". He appears to be looking at the red trend line, not the (unsteady) blue running average, not the fact that temperatures after the 1997 peak dropped to lower than the late 1960s/early 1970s. The blue running average shows that clearly. The nearest I can get to that chart is this one from GISS, but it's very similar, except for the missing early 80s peaks.

Los Angeles annual temperatures 1881-2011 GHCN via GISS

The red running mean has dropped to the 1955/6 level, similar to that for 1976. Of course, if I were a "True Believer" I'd just not see that. Perhaps "True Believers" look at temperature graphs with a right tilt to the head, which always produces a "steady increase", and snowfall graphs with a tilt to the left, which produces a vague childhood memory of what snow looked like.

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