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Geophysical Research Abstracts
Vol. 19, EGU2017-3233-3, 2017
EGU General Assembly 2017
© Author(s) 2017. CC Attribution 3.0 License.
If the Dark Ages solar peak c.525CE caused a c.5m sea-level rise 50-100y
later ("ocean memory"), the stronger 1958 solar "Grand maximum"
presages a >5m rise by 2058: literature review by an impartial geologist
Roger Higgs
Geoclastica Ltd, Bude, United Kingdom (rogerhiggs@hotmail.com)
The 255 authors of IPCC’s “Climate Change 2013: The Physical Science Basis” include no sedimentary geolo-
gists, specialists in ever-changing sea level (SL). According to IPCC the 0.3m SL rise(1) since tide-gauge records
began (c.1700CE, Little Ice Age[LIA] acme) is unprecedented in >2ky, implicating mankind’s CO2emissions.
On the contrary, a c.5m SL rise and fall between c.400CE and 1700 are indicated independently by three lines
of evidence: British archaeology(2,3); worldwide raised-shoreline benchmarks(4); and Red Sea foraminifera O18
fluctuations(5). The c.5m fall is attributable to 590-1640CE cooling (ice growth) shown by a global proxy temper-
ature graph(6; cf.7). This 1ky-long cooling and ensuing 1850-2017 warming, both sawtooth-style, in turn mimic
a 1ky solar decline then rise(8), moreso after aligning the 590CE peak temperature(6) with the c.525CE solar
"Grand maximum" (GM) or near-GM(8). This 65y lag reflects hitherto-neglected ocean-conveyor-belt circulation,
i.e. downwelling Atlantic surface water, variably solar-warmed (depending on solar-governed cloudiness[9]), up-
wells decades later beside Antarctica, returning northward to affect continental air temperatures. The conveyor
slowed in the LIA (c.150y offset between 1280-1700CE cluster of solar Grand minima[8] and 1430-1850 cool
phase[6]). Lately the lag, obvious from visual cross-matching of 1850-2012 instrumental-temperature peaks and
troughs(10) versus the 1700-2016 sunspot chart (Google images), is c.85y (1890 solar trough matches 1975 tem-
perature trough). Similarly, SL(1) clearly lags temperature(10) by 15y (1964 and 1976 temperature troughs match
1979 and 1991 SL troughs). Thus the total SL-solar lag is 100y (85+15). Appreciating the 85y and 100y lags en-
ables vital predictions: sunspots increased (sawtooth-style) from c.1890 until the 1958 GM (the only definite GM
in >2ky[8]), therefore ongoing warming will peak c.2043 (1958+85), and SL c.2058. How high will SL rise? The
1958 solar GM exceeded (95% confidence;8) the c.525CE GM(?) that caused a c.5m rise, but SL has risen just 0.3m
since c.1700(1), so a further 4.7m+ is predictable by 2058. A viable cause is that whenever the sun exceeds the GM
threshold(8), "superwarmed" downwelling Atlantic water eventually upwells at Antarctica, causing runaway retreat
(ice-cliff collapse) of ice-sheet glaciers after melting the buttressing ice shelf. Thus the ocean "remembers" the 1958
solar GM; the Antarctic "time-bomb" is set. The forecast 5m+ SL rise should largely span 2038-2058, as the GM
threshold was crossed c.20y before the GM apex(8). This implies catastrophic acceleration, in c.20y time, to an
average rate >25cm/y (100x current trivial 2.5mm/y). The lookalike Dark Ages SL rise was perhaps c.50% slower
(threshold possibly as much as c.45y before apex[8]). Lack of contemporary descriptions suggests that this SL
rise of c.5m in c.45y (average 0.3mm/day) caused less concern than recurrent Justinian plague and frequent wars.
The Dark-Ages event, preceding industrial CO2emissions by >1ky, absolves mankind of causing climate and SL
change, as does the >1.5ky solar/temperature correlation (mismatches reflect "sliding lag", proxy imperfections and
volcanic aerosol/ash eruptions). Notes: 1/Jevrejeva et al.2008 GeophysResLett35Fig1; 2/Higgs2016a 35th IGC ab-
stract; 3/Higgs2016b GSA Annual Meeting abstract; 4/Fairbridge1961 PhysicsAndChemistryOfTheEarth4Fig.15;
5/Siddall et al.2003 Nature423Fig1; 6/Mann et al.2009 Science326FigS5gAllProxy; 7/Ahmed et al.2013 Na-
tureGeoscience6Fig4b; 8/Usoskin et al.2014 Astronomy&Astrophysics562 L10Fig2; 9/Svensmark2007 Astron-
omy&Geophysics48; 10/IPCC ClimateChange2014SynthesisReportFig1.1a.