California Cities Cool in Last Decade

Meteorologist Jan Null compared the temperature and precipitation records of the National Climatic Data Center for many California cities for the earlier period of 1971-2000 to the period from 1981-2010.  The later period generally was cooler, with increased precipitation.  The temperature records of rural areas commonly do not show the temperature increases commonly seen in cities due to the urban heat island effect.  When even the temperature of cities is going down on most of our West Coast, this is a dramatic event.  It must have been an especially unwelcome outcome for Jan Null, who is an ardent catastrophic man-made global warming booster.  The results of his study were published in the San Francisco newspaper The Chronicle on 6 July with a very nice graphic by Todd Trumbull.

Null claimed that man-made global warming caused the warming in Redding and Fresno and the warmth there caused cool air to be drawn in from the sea to cool the coastal cities.  Why they would have a cooling effect on Los Angeles and San Diego is surely unclear.  Indeed, warm temperatures in the Central Valley usually are caused by high pressure systems that actually cause winds along the coast to go out to sea and the warming of the coastal areas.  Null was apparently desperate to null out the use of his analysis of the data as a refutation of man-made global warming.

One also has to wonder why the data sets used have a 20-year period of overlap.  That 20-year overlap with only 10 years on the earlier end or on the later end, should cause any net cooling effect from 2001 to 2010 compared to the start period for the last cycle of warming claimed generally from 1971 to 1980 to be minimized.  Perhaps that was the point of the long overlap.

Given California's problems with insufficient water supply, the increased precipitation in most of the areas ought to be a positive thing, rather than a catastrophe.  I will not claim the drop in temperatures is a good thing, but it sure does take some wind out of the sails of the catastrophic man-made global warming alarmists who are always using temperature increases, either real or due to urban heat island effects, as evidence that CO2 emissions are going to kill the planet.

Actually, if the increased precipitation is raising the humidity enough, it is possible that the lowered temperatures do not actually mean a reduction of heat energy.  This is because more humid air can hold a lot more energy at a given temperature than drier air.  But, the man-made global warming alarmists do not take note of this when they use any warming of air to claim that it was caused by man's CO2 emissions.