Hurricanes have always been intriguing to me, at first from a navigation point of view, especially regarding the sailing ship era. They revolve with extremely high speeds, but move as a system slowly along, at not much beyond 'bicycle speed'.
Then, more recently, hurricanes were kept responsible for distributing global warming, a logical proposition within their role of tropical circulations. So, I started to look more closely at their origin and behavior. From my days of study I did not remember, that much attention was paid to them, and restarted more or less from scratch. Furthermore, I considered that climate could not be connected to the short term characteristics of weather of one year. For that reason, I decided to add the yearly frequences of the Atlantic hurricanes to decade numbers. The figures could be derived from the well documented diagrams of the authoritative National Hurricane Center in Miami.
While the one year figures did not show any structure to me, the resulting diagram surprisingly did. Summing the frequences clarified cycles of 60 year. From 1851 on we see highs around 1880, 1940 and 2000, and lows in-between around 1910 and 1970. Extrapolating we might expect a new low around 2030, to be followed by a new high around 2060. I communicated the resulting diagram with the National Hurricane Center, and also Woods Hole of the same esteem.
The 60-year hurricane cycle did not only show gradual waves, but also a slight rise. However, not very steep compared to the so-called 'Hockeystick', which rises sharply since 1910, and more recently is skyrocketing. Besides, and interestingly, its peaks do precede the hurricane 'highs' some 10 years, and its 'lows' to half this extent. The entire phenomenon is now known as the 60-Year Climate Cycle. Its occurrence might be a bit disturbing to science, as the physical origin is more likely to come from outside the realm of the earth, instead of being triggered by human cause, as is widely supposed. May be the gradual rise can be attributed to the latter?
For the time being, the 60-year cycle seems to represent sound empirical evidence of the development of our climate. Yet, much of it is still hypothetical, hampered through the lack of a proper correlation of causal nature. Moreover and regrettably, the discussion has taken on quite a political inclination nowadays. Accompanied by founded or unfoumded accusations, outside forces produce an inevitable burden for further research.
This counterproductive development might have been triggered by two seemingly incompatible lines of reasoning. Let us for a start, regard the wave lengths (not heights) of the decadal hurricane frequencies, and those of the hockeystick (again disregarding the wave heights), I observed a peculiar phenomenon, which did not seem to make sense. The hockeystick highs precede some 10 years those of the hurricane frequencies, while the lows precede some 5 years. One would expect from causal reasoning of the climate of the world, at least a different sequence, the other way around. Is there a logical explanation?
Assuming then, as a systems approach, three major determinants of climate development.
Firstly, some external force, resulting in the order of a 60 year cycle of the climate, of mostly unknown origin.
Secondly, and fluctuated by the first determinant, the fundamental heating up of the earth, particularly by the sun´s almost rectangular inclination at lower latitudes.
Thirdly, at higher latitudes, a green house effect.
The two latter ones are 'measured' differently, in two completely separate physical states: water and atmosphere. Hurricane frequences depending on sea water temperatures vs. tree rings depending on atmospheric temperatures. Although oceanic and atmospheric approaches are both indirectly related to their subjects to be measured, as such, they seem to be genuine representatives of climate development, i.e. if measured correctly, and if climate is only defined as outcomes of particular research.
Could the gradual rise of the hurricane graph be explained from global warming? Then, the next reasoning might be adopted. Water masses will take longer to adapt to temperature changes, then air masses. Hence, hotter air masses might after some 10 years have helped enough to heat up surface sea water to such an extent, that more hurricanes result. If less hot, it takes only 5 years to reach some temporary equilibrium at the lows, resulting in less extra hurricanes. (Again, this reasoning can only be true, if the tree ring data have been allocated correctly to the time scale. It should also be noted, that dutch research of tropical tree rings indicates, that latitude is no issue).
What about the climatological phenomena that we observe by eye, then? In this rationale, surface ice will melt sooner as it is exposed to atmospheric temperatures, while submerged ice in contact with colder water, will take much longer. Differences in thermal stability between water and air determine melting behavior of both environments.
Now, what if we again do incorporate the wave heights of both curves in our reasoning? We observe in the latest decades a gradual rise of the hurricane activity versus a sharply upwards turning hockeystick representing the atmosphere. There is no apparent correlation between the hockeystick tree ring data, and hurricane frequences, whatsoever. This is hard to comprehend. At least in more recent decades, one should trace to some extent the risen influence from atmospheric changes to oceanic water masses.
All in all, even if the above reasoning proves to be correct, it will not change my general expectations of climate development and sea water rise. A gentle rise is more likely, in stead of a hockeystick type development, staying rather close to the gradual rise of hurricane frequency waves. In this process, the wave lengths might shorten.
Summarizing, the diagram below represents the NOAA-based Atlantic decadal hurricane frequency developments from 1851-2010 by way of blue columns. The upper line graph, prematurely running out of the diagram, represents the so-called 'hockeystick' findings based on arctic tree ring interpretations (tropical tree rings are said to show comparable outcomes). Obviously, these latter terrestrial figures precede the oceanic temperature findings, although the wave lengths (not the heights) do correspond in general.
Evidence is growing that warming up is staying behind after 2000, crippling the hockeystick development hypothesis. Superficially viewing the '60'-year hurricane cycle, it even seems reasonable to falsify CO2 emissions for warming up/cooling down causes. At first sight, a correlating economic cycle does not fit the hurricane temperature cycle as shown. However, after scrutinizing a 60- to 70-year credit expansion-contraction cycle, suggested in economics, one might unearth some or more explanatory force for the hurricane cycle as it did develop during 160 years.
