A hard-science approach to Kondratieff's economic cycle

- Kondratieff's economic cycle (K-cycle) can be evidenced via variations in the rate of energy consumption.
- Several other human endeavors/phenomena resonate with the K-cycle.
- The K-cycle may have its origins in a climatic variation or in the active human lifespan.
- All evidence for its existence carries confidence levels that are poor by scientific standards.
- There is some evidence that the K-cycle may be beginning to wash out.

In an effort to evidence the Kondratieff cycle more scientifically than the way economists do, physical variables are studied rather than monetary indicators. Previously published graphs are reproduced and updated here with recent data. A cyclical rather regular variation of energy consumption reveals a 56-year cycle. A dozen human endeavors/phenomena, such as bank failures, homicides, hurricanes, feminism, and sunspot activity are shown to resonate with this cycle. Possible explanations for this phenomenon may have to do with a climatic variation or with the length of time any individual actively influences the environment. There is some evidence that the cycle may be getting shorter in amplitude and duration in recent years. All quantitative confidence levels involved in these observations are poor by scientific standards and permit critics to question the very existence of this phenomenon.