Guest essay by Eric Worrall
One of the simplest statistical tools used by investors is a moving average plot. If you plot the average share price of a company, or other investment product, with different smoothing periods, on the same graph, a crossover between the different plots can provide early warning of an imminent change in trend – a buy or sell signal.
“A moving average, as a line by itself, is often overlaid in price charts to indicate price trends. A crossover occurs when a faster moving average (i.e., a shorter period moving average) crosses a slower moving average (i.e. a longer period moving average). In other words, this is when the shorter period moving average line crosses a longer period moving average line. In stock investing, this meeting point is used either to enter (buy or sell) or exit (sell or buy) the market.”
The interesting thing about moving averages is they can provide useful, actionable information, without requiring any knowledge of the nature of the underlying commodity.
So what happens if we create a moving average plot of global temperature (in this case Hadcrut4)?
What is immediately apparent is we may be in the early stages of a significant inflection point – it is too early to tell for sure, but the beginning of an inflection which appears to centre on the early 2000s seems very similar to the inflection which occurred in the 1940s, heralding decades of cooling temperatures.
If the numbers I was plotting was the value of an investment, I would interpret the chart as a strong “sell” signal – a warning that a substantial drop could be imminent.
UPDATE: A previous post on WUWT by David Dohbro also comes to the same conclusion, and has a more detailed analysis: