Global Warming Science - www.appinsys.com/GlobalWarming
The Sixty-Year Cycle
[last update: 2010/06/05]
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Cycles are apparent in climate data. This document examines the appearance of the approximately 60-year cycle that shows up in many areas. This cycle length is not exactly 60 years and varies by a few years between various climatic phenomena and locations.
Climate models do not account for this cycle.
[update 2010/06/05: “El Nino” section added] [update 2010/06/04: “Solar System Influence” section added] [original document: 2010/02/21]
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Global Temperature Anomalies
The following shows the Climatic Research Unit global average temperature anomalies (the IPCC uses data provided by HadCRU – plot from: [http://hadobs.metoffice.com/hadcrut3/diagnostics/global/nh+sh/]). Two cycles have been highlighted in rectangles (not peak-to-peak). The final part of the figure shows the cycle from the second rectangle, changed to red and superimposed on the first cycle (vertically shifted by 0.3 degrees).
As can be seen from the above figures, the two cycles were nearly identical, and yet the IPCC says the models can explain the early 1900s cycle with only natural forcings, but anthropogenic CO2 is needed for the later cycle. There appears to be a serious problem with the models when two identical cycles have two very different causes.
The following figure shows the same Hadley plot stretched vertically to highlight the cycles.
The cycle length is approximately 62 years, with maxima around 1879, 1942 and 2002, and minima around 1910 and 1972.
When the claim is made that the Earth has warmed 0.74 degrees from 1906 – 2005 (IPCC AR4 [http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr_spm.pdf]), they are spuriously ignoring the 60-year cycle and arbitrarily choosing a start and end for a linear trend within a non-linear cycle. The red line on the figure below shows the 0.74 degrees per century. The linear warming trend shown when accounting for the cycle is actually about 0.4 degrees per century as shown by the blue line on the figure below.
The IPCC also claims in the same AR4 summary document that “The linear warming trend over the last 50 years (0.13 [0.10 to 0.16]°C per decade) is nearly twice that for the last 100 years.” This is shown by the green line on the figure above. They call this “acceleration” of the warming trend, completely ignoring that a linear trend cannot be calculated arbitrarily in cyclical data.
The IPCC is either stupid, or trying to deceive by obfuscating the statistics (the latter is more likely).
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Atlantic Multidecadal Oscillation (AMO)
The following figure shows the AMO anomalies from 1850 to 2009 [http://en.wikipedia.org/wiki/File:Amo_timeseries_1856-present.svg].
The cycle length is approximately 62 years with maxima around 1878, 1943 and 2004, and minima around 1912 and 1974.
The AMO cycle is very close to the global temperature cycle in terms of cycle length and occurrence of maxima / minima.
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Southwest US Drought Cycle
The following figure shows the southwest United States drought index 1900 - 2002 [http://www.ncdc.noaa.gov/img/climate/research/2002/may/Reg107Dv00_palm06_01000502_pg.gif]
The cycle length is approximately 64 years, with maxima (wet) around 1918 and 1982 and a minimum (drought) in 1955.
The southwest US PHDI has about a 5 year lag from the AMO.
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Length of Day / Zonal Atmospheric Circulation Index
A UN Food and Agricultural Organization (FAO) report on “Climate Change and Long-Term Fluctuation of Commercial Catches”, 2001 [ftp://ftp.fao.org/docrep/fao/005/y2787e/y2787e01.pdf] provides the following figures showing length of day (LOD) inverted (left) and the Zonal Atmospheric Circulation Index (right). Both exhibit an approximately 60-year cycle.
The FAO report stated: “Spectral analysis of the time series of dT, ACI and Length Of Day (LOD) estimated from direct observations (110-150 years) showed a clear 55-65 year periodicity. Spectral analysis of the reconstructed time series of the air surface temperatures for the last 1500 years suggested the similar (55-60 year) periodicity. Analysis of 1600 years long reconstructed time series of sardine and anchovy biomass in Californian upwelling also revealed a regular 50-70 years fluctuation. Spectral analysis of the catch statistics of main commercial species for the last 50-100 years also showed cyclical fluctuations of about 55-years.” The following figures are from that report and are also viewable at: [http://www.fao.org/docrep/005/Y2787E/y2787e03a.htm]
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ThermoHaline Circulation (THC)
William Gray, the foremost hurricane expert and Professor of Atmospheric Science at Colorado State University published the following figure showing a 6-year cycle in the North Atlantic thermohaline circulation (W. M. Gray, 2009: Climate change: Driven by the ocean – not humans. The Steamboat Institute Conference, Steamboat Springs, Colorado, August 29, 2009. [http://tropical.atmos.colostate.edu/Includes/Documents/Presentations/graysteamboat2009.ppt])
This may be related also to the AMO.
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El Nino
The following figure shows “21-year sliding window correlation between Nino3AM and CPI AM (thick solid line), and between Jan-Feb TA cross-equatorial SSTA gradient and CPI AM (thin solid line). The sign of the first correlation is reversed. The dashed line is the 5% (2 sided) significance level based on the Student's t distribution (N-2 degrees of freedom) for the null hypothesis of no association. Bars are the number of Nino3AM events above 28oC in a 21 year sliding window (y axis values to the right).” [http://shadow.eas.gatech.edu/~kcobb/seminar/chiang00.pdf] Nino3AM is the Nino 3 region index April-May and CPI is a precipitation index related to Brazil rainfall. The correlation between these two (thick line) shows a 60 year cycle, as does the number of Nino 3 AM events above 28 degrees in a 21-year sliding window (vertical bars).
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Climate Models
The following figure (left) shows climate model outputs from the IPCC 2007 AR4 Figure SPM-4 [http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr_spm.pdf]) In this figure, the blue shaded bands show the result of 19 simulations from 5 climate models using only the natural forcings. Red shaded bands show the result of 58 simulations from 14 climate models including anthropogenic CO2.
The following figure (right) shows the Hadley / Met Office data shown at the start of this document, superimposed on the models. (The zero location is different since the model plot is based on a 1901-1950 average whereas the Hadley plot is based on a 1961-1990 average.)
The above figures show the following:
The following figure compares the two recent 60-year cycles (shown previously near the start of this document). There appears to be a serious problem with the models when two identical cycles have two very different stated causes – one natural, the other CO2-induced.
If the climate models cannot reproduce the 60-year cycle that is evident in many climate phenomena, there is clearly a fundamental problem with the models.
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Solar System Influence
Nicola Scafetta has identified the change in the location of the center of mass of the solar system (CMSS) as a possible mechanism driving the 60-year cycle. (Scafetta, N., “Empirical evidence for a celestial origin of the climate oscillations and its implications”, Journal of Atmospheric and Solar-Terrestrial Physics (2010), doi:10.1016/j.jastp.2010.04.015 [http://arxiv.org/PS_cache/arxiv/pdf/1005/1005.4639v1.pdf])
Scafetta shows the following figures described as: “[A- (left)] Rescaled SCMSS 60 year cycle (black curve) against the global surface temperature record (grey) detrended of its quadratic fit; [B- (right)] Eight year moving average of the global temperature detrended of its quadratic fit and plotted against itself shifted by 61.5 years. Note the perfect correspondence between the 1880-1940 and 1940-2000 periods. Also a smaller cycle, whose peaks are indicated by the letter “Y”, is clearly visible in the two records. This smaller cycle is mostly related to the 30-year modulation of the temperature. These results reveal the natural origin of a large 60-year modulation in the temperature records.” (SCMSS – Speed of the CMSS)
(Note: The term “barycenter” refers to the center of gravity of a system, which would be the same as the center of mass in a uniform gravitational field, and thus the two terms are often interchanged.)
As the planets orbit around the sun, the sun’s position also changes as the whole solar system orbits around the CMSS, whose position changes as the relative positions of the planets change. The planets / sun influence this based on their relative mass. The following figure (left) show a gravity simulation of the solar system barycenter position. The center figure shows the hypothetical barycenter movement with Jupiter removed from the system showing that Jupiter causes most of the wobble. The right-hand figure then removes Saturn. Once Neptune is removed the effect of the remaining planets is barely noticeable (not shown below). [http://www.orbitsimulator.com/gravity/articles/ssbarycenter.html]
Jupiter has the largest mass of any planet and thus is the most influential. The Wolf cycle (solar sunspot cycle) has a period that fluctuates but averages 11.2 years. Jupiter’s solar orbital cycle is 11.9 Earth years. Saturn, the second-largest planet, has a solar orbital cycle of 29.4 Earth years. This leads to Jupiter-Saturn conjunction every 19.9 years (J/S Synodic Cycle). (As a coincidence, in the Maya calendar 1 Katun = 19.7 years.) A full cycle of Jupiter / Saturn around the sun (J/S Tri-Synodic Cycle) is 59.6 years – in other words it takes 60 (59.6) years for the Earth / Jupiter / Saturn reach the same relative alignment around the sun.
The following figure shows the speed of the Sun relative to the CMSS showing “20 and 60 year oscillations”. (From the Scafetta paper referenced above.) It shows a 60-year cycle with peaks similar to the global average temperatures shown at the start of this document – around 1880, 1940 and 2000.
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