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 et.al., 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.|
|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.