"ICEHOUSE, GREENHOUSE, MADHOUSE” – HAVE WE ARRIVED?

The sedimentary systems of the Bahamas and other global sites reveal the relative fluctuations of sea level during marine isotope stage (MIS) 5e (~130 to 118 ka). The changes of sea level during MIS 5e were of paramount importance in Conrad Neumann’s “warehouse of ideas.” Reefs, constructional terraces and bioerosional notches were the early focus in Neumann and Moore’s (1975 QR 5(2)) paper. Neumann and Macintyre presented their “Give up, Catch up or Keep up” paper in 1985 at the 5^th International Coral Reef Congress (v3) in Tahiti. This paper implied that coral reefs may not accurately record rapid vertical sea-level changes. When they met in Tahiti, Conrad noted Hearty’s clumsy presence when he fell off the poorly lit stage during concluding remarks of his first international talk.

Hearty’s PhD thesis in the Mediterranean documented low 5e terraces and high notches in “Eutyrrhenian,” deposits, which converged with the findings of Neumann. Hearty was also influenced by thesis advisor JT Hollin’s Antarctic ice surge papers, particularly 1972 (QR 2, 401), which undoubtedly inspired JH Mercer’s1978 (Nature 271) “a threat of disaster” by runaway CO₂, and incipient ice collapse. Convergent evidence for a “bumpy” 5e curve was documented in Neumann and Hearty 1996 Geol (24:9) and refined in subsequent papers.

Tormey joined the fray with a thesis on Eleuthera (1999), adding detailed outcrop descriptions of chevron ridges and runup deposits. Collaborations between Neumann, Hearty, Tormey, and their students continued to describe double-5e reefs and foreshore successions, late 5e sea-level rising to +6-9 m (2007, QSR 26:2090), and the mounting evidence for superstorms that parsimoniously explain chevron ridges, wave runup deposits, and the transport of giant boulders (2017 Mar Geol 390:347).

Over the years, our sea-level and superstorm observations have generated much controversy among our peers, reef daters, isotope people (who preferred rounded or flat-topped curves), and tsunamists! However, interestingly, probabililists (Kopp et al, Nature 2009; 462) and isotopers (Rohling et al, Nature 2019, 10:5040) are recently finding our bumpy +6-9 m sea level curves more attractive! Finally, to Conrad’s point: “between the greenhouse and the icehouse lies a climatic “madhouse”! The greenhouse is here and the madhouse door is open!