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California Aggregate Data

Annual Precipitation: 27 Station Aggregate Average

CA aggregate prcp vrs CO2.jpg

The trend for aggregate precipitation in California based equally on the annual rainfall at each of the 27 weather stations tested, shows a slight increase overall, of about 0.78 inches per century.  The Pearson Correlation Coefficient between the precipitation and the atmospheric CO2 concentration is r = -0.0047 over the entire period from July 1919 through June 2017.  The negative value indicates any correlation is an inverse one, but the very low absolute value for the coefficient, much less than 0.1, indicates the correlation is very weak to none.  Aggregate California precipitation does not correlate with rising CO2 concentrations.

Aggregate California Extremes of Temperature

CA aggregate percent hottest and coldest

In this graph, the number of days in the hottest hundred in the 1900s and the 2010s have been extrapolated out to the full ten years, based on the rate per year over the years for which data is available.  The cold and heat indices in the above graph are based on the percent distribution of the hundred coldest daily minimum temperatures and the hundred hottest daily maximum temperatures from each weather station, adjusted to give each of the 27 weather stations equal weight.  The trend lines show that both cold and hot extremes have generally decreased, but also show that cold extremes have decreased more dramatically than hot extremes.  The correlation factor between cold extremes and CO2 is r = -0.24, indicating a very weak inverse corrrelation, while between hot extremes and CO2 it is r = 0.17, indicating a very weak direct correlation.  A correlation is necessary but not sufficient to prove a cause and effect relationship.  If there is a cause and effect relationship between these extremes of temperature and increased CO2, it is a very weak negative correlation for extremes of cold, and a very weak positive correlation for extremes of heat.

CA aggregate 3 6 9 day heatwaves & CO2.j

The number of heatwaves among the hottest hundred during the 1900s and the 2010s have been extrapolated out to the full ten years of the decade, based upon the number of heatwaves per year over the period for which data were available.  The trends since the 1900s are toward fewer heatwaves, although there is an upturn over the past two decades.  The Pearson correlation coefficient between CO2 and 3-day heatwaves is r = 0.056, between CO2 and 6-day heatwaves it is r= 0.12, and between CO2 and 9-day heatwaves it is r = 0.21.  The correlations can be characterized as very weak to none for heatwaves of all three durations.  There may be no cause and effect relationship between CO2 and heatwaves, or at most there may be a very weak cause and effect relationship.

CA aggregate Tmin Tmean Tmax & CO2.jpg

The graph above shows the aggregate average annual minimum, maximum, and mean temperatures for the 27 California weather stations studied here.  The trend lines show an increase in the average annual minimum temperatures at a rate of 2.7 Fahrenheit degrees per century.  Average annual maximum temperatures increased much more slowly, at about 0.74 Fahrenheit degrees per century.

The Pearson correlation coefficient between CO2 and average minimum temperatures in r = 0.69, in the range of moderate correlation.  The average maximum temperatures correlate with CO2 with r = 0.31, toward the low end of a weak correlation.  It is possible that there is a moderate cause and effect correlation between CO2 and average annual minimum temperatures in California, and a weak cause and effect correlations between California average annual maximum temperatures.  These moderate and weak correlations may also be due to both of these factors being affected by something else, without any cause and effect relationship.

California Drought Index

Sea Level from California Tide Gauges

Palmer drought index.jpg

There is at most a very weak correlation seen between rising CO2 in the atmosphere and drought conditions in California.

Sea Level in California

Table CA Tide Gauge sea level.jpg

The table above shows the GPS ground movement vertical trend, the trend in relative mean sea level measured by tide gauges over the period of record and also from 1950 through 2017.  The absolute change in sea level shown is the sum of the vertical ground movements and the tide gauge relative sea level changes.  With perfect data, the absolute sea level trends should all be identical.  The wide variations in these absolute sea level trends since 1950, from as low as 0.28 mm per year to as high at 2.06 mm per year, show the uncertainties in these values.  An accepted value for the absolute sea level trend is about 1.7 mm per year (Journal of Coastal Research Vol 27, issue 3: p. 409).  However, some scientists show a recent acceleration in absolute sea level rise to 3.2 mm per year, based on satellite measurements.  There is little evidence of this acceleration in the California Tide Gauge records, with the gauges from Crescent City, San Francisco, and Santa Monica showing a slightly decreased rate in sea level rise, while Alameda, Los Angeles, La Jolla and San Diego showing a slight increase in the rate.  None of the gauges show a change to an increase of 3.2 mm per year, that the satellite data seems to indicate.

6 CA tide gauge & CO2 trend.jpg

The graph above shows the average relative sea level for the six California coastal tide gauges at San Diego, La Jolla, Los Angeles, Santa Monica, San Francisco, and Crescent City.  The trend in sea level over the entire period of record is an increase of about 1.44 mm per year, with the trend from 1950 through 2016 dropping to about 1.37 mm per year.  The Pearson Correlation Coefficient between rising sea levels and CO2 over the entire period is strong, with r = 0.82, but during the era of rapidly rising CO2 since 1950, the correlation coefficient is only moderate, with r = 0.65.

Rising global oceanic temperatures are known to increase the fraction of CO2 in the atmosphere, as it is less soluble in sea water at higher temperatures, and also there is much more CO2 dissolved in earth's oceans than is found in earth's atmosphere.  Sea level is also increased by expansion with rising temperatures.  These two effects account for at least a large portion of the correlation between sea level and atmospheric CO2 during the rising oceanic temperatures since the coldest part of the Little Ice Age in the mid-seventeenth century.  The fact that the correlation between atmospheric CO2 and rising California sea level has weakened since 1950, when anthropogenic CO2 has increased most rapidly, suggests a relatively weak cause and effect relationship between the two, if any.

acceleration of CA sea level 2.jpg

The graph above shows the differences in the six tide guage average annual rate of sea level rise across thirty year periods.  For example, 1855 averaged 6954mm of relative sea level, but the following year in 1856 averaged 6860mm, representing a change of -92mm per year from 1855 to 1856.  Thirty years later, the average sea levels in 1884 and 1885 were 7016mm and 6971mm, showing a change of -45mm per year.  The difference between this later rate and the earlier rate divided by the years elapsed gives the average acceleration over this thirty-year period: (-45mm/yr-(-92mm/yr))/30yr = 1.63mm/yr^2, the first data point on the graph for 1885.  The linear trend in acceleration is a flat line, and there is essentially zero correlation between sea level acceleration and carbon dioxide in the atmosphere.  There is no evidence in these California tide gauge data that CO2 has caused an acceleration in sea level rise through 2016.

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