Guest essay by David Archibald
Wiggle-matching has been used by the best. Hubert Lamb, considered to be the most meticulous climatologist of all time, used wiggle-matching in this wind data graph he published in 1988:
He had plotted up 600 years of wind data at London, noted a 200 year periodicity and copied the line 200 years to the right to make a forecast.
One of the puzzles of the last 300 years of climate is the temperature drop of 1740. It came out of the blue after a number of warm years in the 1730s. There is nothing in the Be10 record or the volcanic record to suggest a cause.
It came a couple of years after the peak of a fairly strong solar cycle. The event of 1740 attracted the attention of Briffa and Jones in their 2006 paper “Unusual Climate in Northwest Europe During the Period 1730 to 1745 Based on Instrumental and Documentary Data”. From the abstract of that paper,” This study focuses on one of the most interesting times of the early instrumental period in northwest Europe (from 1730–1745) attempting to place the extremely cold year of 1740 and the unusual warmth of the 1730s decade in a longer context.” The only conclusion that they came to was climate might vary more than is commonly accepted.
So what does that period up to 1740 wiggle-match with? It matches with the warmth of the last 30 years:
The graph above shows the Central England Temperature (CET) record from 1703 to 1745 as the blue line. Plotted on it is the CET record from 1978 to 2012. Normally when you align 34 year lengths of temperature records you don’t get any correlation. The correlation on this particular matchup is 0.112. The statisticians amongst us can argue over whether or not anything can be read into that. If something can be read into it, we only have to wait two years to experience the consequences. The spike down is also prominent in the de Bilt record: