Correlation of extreme hurricanes, AGW, and solar cycles

[WolfStock1]

Prompted by Hurricane Melissa  - what's the correlation of extreme hurricanes and AGW, and solar cycles?

When looking strictly at Cat 5's - they  definitely seem to be getting more frequent over time, but also seem to correlate heavily with the solar cycles; specifically being more frequent during peaks of solar cycles, with perhaps some lag (more frequent on the "back side").

Here's list of Cat 5's by year:

https://en.wikipedia.org/wiki/List_of_Category_5_Atlantic_hurricanes

Haven't charted yet, but there definitely seems to be strong correlation with the peak and/or back side of the peak of solar cycles; specifically cat 5 frequency peaking:

https://en.wikipedia.org/wiki/Solar_cycle

Haven't charted the correlation (maybe someone else has) but it definitely seems to be there; looking at the list of Cat 5's at least.   The correlation seems to be strongest in recent years:

1924
1928  - solar cycle 16 peak
1932  - solar cycle 16 backside
1932
1933
1933
1935
1938  - solar cycle 17 peak backside
1944  - off-cycle
1953  - off-cycle
1955
1961  - solar cycle 19 peak backside
1961
1966
1967
1969  - solar cycle 20 peak
1971
1977
1979  - solar cycle 21 peak
1980
1988
1989  - solar cycle 22 peak
1992
1998
2003  - solar cycle 23 peak backside
2004
2005
2005
2005
2005
2007
2007
2016  - solar cycle 24 peak backside
2017
2017
2018
2019
2022
2024
2024
2025  - solar cycle 25 peak
2025
2025
 

Odd thing is that a google search mentions *anti-correlation* of hurricane activity and solar cycles - but that's not what I see here, at least looking at the Cat 5's.   Perhaps during peak periods there are less overall hurricanes, but more Cat 5's (?).

[ATDoel]

I posted a link to the study in the other thread, here it is.  Effects of Solar Variability on Tropical Cyclone Activity - Nayak - 2024 - Earth and Space Science - Wiley Online Library

To me the most obvious trend here is the increasing number of Cat 5s, regardless of solar activity.  We've had 11 in the last 10 years, 17 in the last 20.  There's no other 20 year period that even comes close to that.  That has nothing to do with the solar cycles.

[Typhoon Tip]

Perhaps during peak periods there are less overall hurricanes, but more Cat 5's (?)"  

that was gonna be my knee jerk guess, yeah.  In other words,  occurrence counts of TCs ( in general) per year may be well correlated, but category 5s may require a broader set of favorable parameters. 

Not that anyone asked but ... I've wondered in the past if these upper tier TC frequencies are more endemic to this particular micro geological span of time.  They will tend to become less when/if the atmospheric thermodynamic rest state catches up to the oceanic heat phenomenon - if/when that happens.   TC mechanics require a thermodynamic initial state, from the quasi oceanic-atmospheric coupling at the bottom to the way the curve is all the way up to 100 mb.  If the bulk troposphere sounding was to modulate associated with CC, that may have an impact on the vitality of these storm engines - later generations... But for now, we have hotter than normal OHC underneath a TC viable sounding and that's a powderkeg  

[Roger Smith]

The anti-correlation idea may have come from 2004-05 which does not fit the theory. 

I noted in the hurricane Melissa discussion that 1780, a very bad year in the Caribbean, was also two years after a large solar peak in 1778, and the Long Island express (1938) while not a cat-5 was a year after a solar peak. 

Rather active years that came before a solar peak would include 1916, 1936, 1944 and 1998, as well as 2020. 

1887 is closer to a solar minimum like 2004 and 2005. 

1893 was a very active tropical year and there was a solar peak in 1893-94. 

The least active season in recent times, 1910, came at a solar minimum. 

I would include Andrew on the basis of the 1989 cycle peaking rather broadly from 1988 to 1991, the "1989" designation is only barely valid, and in fact also the 1968 peak had a very well defined secondary peak in 1972 (Agnes). 

Perhaps if there is a correlation, it is not because the solar conditions induce stronger hurricanes to form, but because some mechanism in the solar system peaks at that time and is responsible for these two different effects. Clearly it is not a necessary condition given the number of counter-examples. But it seems relatively robust over about twenty solar cycles, before 1780 we probably don't have enough data to form any conclusions. 

[FPizz]

1 hour ago, Roger Smith said:

The anti-correlation idea may have come from 2004-05 which does not fit the theory. 

I noted in the hurricane Melissa discussion that 1780, a very bad year in the Caribbean, was also two years after a large solar peak in 1778, and the Long Island express (1938) while not a cat-5 was a year after a solar peak. 

Rather active years that came before a solar peak would include 1916, 1936, 1944 and 1998, as well as 2020. 

1887 is closer to a solar minimum like 2004 and 2005. 

1893 was a very active tropical year and there was a solar peak in 1893-94. 

The least active season in recent times, 1910, came at a solar minimum. 

I would include Andrew on the basis of the 1989 cycle peaking rather broadly from 1988 to 1991, the "1989" designation is only barely valid, and in fact also the 1968 peak had a very well defined secondary peak in 1972 (Agnes). 

Perhaps if there is a correlation, it is not because the solar conditions induce stronger hurricanes to form, but because some mechanism in the solar system peaks at that time and is responsible for these two different effects. Clearly it is not a necessary condition given the number of counter-examples. But it seems relatively robust over about twenty solar cycles, before 1780 we probably don't have enough data to form any conclusions. 

Does this include the rest of the world or only the Atlantic?  A lot more storms to study i would assume.