I am reminded of a February 2007 post over at Climate Audit on a Simon Holgate sea level changes paper published in GRL, and a related poster presentation. Holgate claimed that sea levels rose more in the first half of the 20th century, than in the second half. The same could be said for solar activity.
Plotting the sun spot data on to Holgate’s graph of sea level changes produces an interesting result:
Holgate 2007 Figure 2. Comparison of the global mean decadal rates of sea level change based on the nine records with the rates from the 177 stations used in HW04. All rates are corrected for glacial isostatic adjustment and inverse barometer effects. The shaded region indicates standard error. The sun spot numbers are from here.
The coincidence is good except for the last sunspot cycle. Note also that the sea level series are decade mid-point, so the sunspot series should be read as displaced 5 years to the left. Does this mean that the correlation is real, but the effect of CO2 or something else has become apparent during the last solar cycle? Who knows!?
Whilst on the subject of sea level rise, there is this graph below from NASA-GISS: Sea Level Rise, After the Ice Melted and Today
MWP = meltwater pulse. MWP-1A0, c. 19,000 years ago, MWP-1A, 14,600 to 13,500 years ago, MWP-1B, 11,500-11,000 years ago, MWP-1C, ~8,200-7,600 years ago.
I think the above graph puts modern sea level rise into perspective.
References:
S. J. Holgate, On the decadal rates of sea level change during the twentieth century. GRL, 2007.
Jennifer Marohasy BSc PhD has worked in industry and government. She is currently researching a novel technique for long-range weather forecasting funded by the B. Macfie Family Foundation.