NZCLIMATE & ENVIRO TRUTH NO 156
OCTOBER 1ST 2007
Dr Vincent Gray
The climate seems to be unaffected by emissions of greenhouse gases, but it does fluctuate in a manner which is only partly monitored by the weather forecasting people.
While some of these fluctuations are irregular, and currently little understood,
there are now a whole number of influences which have been recognised, and some of these impose a fairly regular oscillation of the climate system. This Newsletter attempts to list some of the ones which have been identified.
The most familiar of all the oscillations is the series of ice ages, which recur every 100,000 years. The attached diagram shows how this cycle is influenced by the precession, obliquity and eccentricity of the earth's orbit (first proposed by Milankovitch in 1920). The diagram also shows that variation in Solar Forcing had a big part to play.
We are currently right on the top of the latest phase of this cycle and an imminent ice age cannot be all that far away. As soon as the temperatures go down (as is already happening in New Zealand) and everybody realises that the global warming theory is rubbish, we can confidently expect that the climate scientists will switch to scaring us about the coming ice age once again, as they did in the 1970s.
There is a great deal of evidence for a 1500 year climate cycle. Fred Singer and
Dennis Avery have recently assembled the evidence for this in their book
"Unstoppable Global Warming", obtainable from his website:
Many recent studies have found a relationship between the sun's variability and the climate. The sunspot cycle of about 11 years is often evident in climate data
and recent increases un solar activity are widely linked to the recent relatively
H Svensmark 2007: Proceedings of the Royal Society A 463 385-396, has shown that the changes in the sun are enhanced by the accompanying reduction in cosmic ray intensity which reduces cloud cover.
N Scafetta and B J West 2005: Geophysical Research Letters 32 doi:1029/2005GL025539, reckoned that 25-35% of the "warming" from 1986-2000 was due to changes in the sun. Since most of the rest was due to urbanisation effects on the temperature data, not much is left for "global warming"
D C Archibald Energy and Environment 2006 17 29-35, predicts a fall in temperature of 1.5ºc by 2020 from analysis of weak solar maxima of recent solar cycles.
Recently, I have pointed out that the temperature oscillation identified by M E
Schlesinger and Ramankutty: Nature 1994 397 723-726, of 65-70 years can be found in many reliable temperature records from the USA, China, and many individual long-term stations. . This cycle has been shown to result from alternate reinforcement and opposition of the main ocean oscillations, Pacific Decadal oscillation, El Niño/Southern Oscillation, and North Pacific Oscillation, by Tsonis. A A, K Swansen, S Kravisov, 2007: Geophysical Research Letters 34, L13705.doi:10:109'GL030288
According to this cycle we are currently at the top of the cycle, and today's
warmish temperatures were last seen in 1950 and 1885. Cooler temperatures were in 1915, and 1980, with the next cool year being in 2040.
Further details are to be found in my paper at
We will soon know if the climate is actually cyclic instead of irreversibly warming.