Holocene rapid (decades) multi-metre marine transgressions by climatically driven Antarctic ice-collapse events. Another event imminent?

Roger Higgs 

The controversial 1961 'Fairbridge Curve' of Holocene global sea-level (SL), showing metre-scale (to ~5m) oscillations based on carbon-dated geological index points (SL 'benchmarks''), is vindicated by syntheses (companion-articles by present author) of the literature on: (1) Holocene sea level, exposing flawed assumptions and methods in constructing non-oscillating SL curves; and (2) English archaeology, its SL significance previously underappreciated, revealing a ~4m SL rise that spanned only ~70 years (~430-500AD), equating to Fairbridge's 'Rottnest transgression', but far better-dated (dendrochronology, coins, pottery). The present contribution, a review of polar glaciological literature, argues that 'Fairbridge-type', large (m), rapid (decades) SL rises result from Antarctic 'MICI' ice-cliff-collapse events. The Rottnest rise (began ~430AD) is attributed here to a 12-year Arctic warm spike (Sun-driven?) that peaked 402AD; the 30-year lag is the delay for downwelling 'overwarmed' Arctic sea-surface water to reach Antarctica by 'conveyor-belt' ocean circulation. Since 2005, anthropogenically-boosted Arctic average temperature has continuously exceeded the ~402AD peak, portending another MICI-driven rise, starting by ~2035 (2005 plus lag), likely to raise SL at least 3m by ~2100. Closely monitored Antarctic glaciers indeed show signs of approaching failure. On the Fairbridge Curve, each SL rise is closely followed by a SL fall of similar magnitude, probably intrinsic to the MICI process.