One point, which comes across resoundingly from the historical charts, is how volatile commodity prices can be in the short term, even within a long-term trend that is clear with the benefit of hindsight. A period receiving renewed attention at present is the Great Inflation of the 1970s and 1980s, when the 12-month change in US CPI averaged close to 8% between 1972 and 1983. What is typically remembered of this period is that commodities surged, rebasing to a new price level many times higher than before.
This is true, but a closer look at the data shows the huge short-term variation in this trend. Take gold, for example. The gold price rose by a factor of six from 1971; fell 40% from a 1975 high; increased another sixfold over the subsequent five years; before halving in value from 1980. It was a similar story for other commodities – copper and corn prices had large trends, upwards and downwards, over the same 12 years. Oil, meanwhile, peaked in 1980 and drifted lower, before prices collapsed from the final quarter of 1985 when Saudi Arabia ramped up production.
Rebased Commodity Prices During Inflationary Environments Since 1960