Nils-Axel Mörner
Paleogeophys & Geodynam, Sweden
Title: New York city: Is the threat of sea level flooding trustworthy?
Biography
Biography: Nils-Axel Mörner
Abstract
Hazard predictions must be anchored in well-established obser-vational facts to be meaningful and trustworthy. The tide-gauge station in NYC (The Battery) gives a long term mean rise of 2.84 ±0.09 mm/yr, which does not imply too serious problems for centuries to come [1], (curve 2 in Fig. 1). Recently, however, it has been claimed [2] that there is a potential threat of a 0.6 m rise in 2050, 2.6 m rise in 2100, 10.5 m rise in 2200 and 17.7 m rise in 2300 (curve 1 in Fig. 1). This is a model-based view, which is based on a totally hypothetical “enhanced Antarctic Ice Sheet (AIS) melting”. We have investigated the global eustatic sea level changes [1] and been able to show that sea level is not in a drastically rising mode. Whilst the regional eustatic factor in the North Atlantic seems to be about +1.0 ±0.1 mm/yr, key sites from all over the world are indicative of present stability (i..e. ±0.0 mm/yr), at least for the last 40-70 years [3]. Also, the satellite altimetry records must be revised to values around +0.55 ±0.1 mm/yr [3]. Detailed sea level studies in the Maldives, Bangladesh, Goa and Fiji [e.g. 4] indicate that the global sea level changes during the last 500 years have been dominated by “rotational eustasy” (not glacial eustasy, as usually assumed), which is driven by solar– planetary interaction with the Earth-Moon system. In the model of [2], the author use the IPCC climate model RCP85 with an extra and totally hypothetical enhanced Antarctic Ice Sheet melting. This hypothesis is convincingly demolished by the observed present increase of the Antarctic Ice Sheet [5]. We conclude that available facts strongly support a modest rise in local sea level (curve 2, Fig. 1), and that the model-based assessment (curve 1, Fig. 1) totally fails in predicting future changes in a meaningful and realistic way. The megacity of New York have enough of problems and threats (terrorism, earthquakes, solar flare black-out, pandemic events, etc), to be bothered by largely exaggerated flooding prospects based on models and hypothetical assumptions ignoring facts observed and measured in nature.