This is a blatant case of cherry picking to confirm a Singer’s position while ignoring a significant all other instrumental sea level data that may contradict that position. This fallacy is a major problem in public debate. It reminds me of the Houston and Dean paper that was published by the Journal of Coastal Research which also cherry picked data to support their argument that there is no acceleration in sea level. The Houston and Dean paper caused many problems to the advancement of adaptation practices in the US to sea-level rise.

It is interesting that this opinion piece starts off with “Munk’s enigma”. This was introduced by famed oceanographer Walter Munk in a 2002 paper published in Proceedings of the National Academy of Sciences. The enigma refers to a key discrepancy between the amount of sea-level rise believed to have occurred during the 20th century and the effects it should have produced on the planet — specifically, on the Earth’s rotation. So in addition to all the devastating and obvious effects sea-level rise will produce on the planet, such as flooding and erosion, sea-level rise also has the more subtle, but nonetheless mind-boggling ability to alter the way the Earth rotates on its axis. In a recent paper, Jerry Mitrovica and an interdisciplinary team of colleagues claim to have resolved the enigma. They reinforce the awe-inspiring power of climate change to produce global-scale effects, changing the planet’s very rotation. I don’t understand the relevance of citing Walter Munk to support Singer’s argument.

They are not Al Gore’s numbers! These are the sea-level rise projections from the scientific community who go through the peer review process. That is, the evaluation of the sea-level projections by one or more people of similar competence to the producers of the work (peers). It constitutes a form of self-regulation by qualified members of a profession within the relevant field. Peer review methods are employed to maintain standards of quality, improve performance, and provide credibility of sea level projections.

But there is one caveat that I would like bring up, whether sea level showed an acceleration or not in the satellite era is of less importance compared to the rates of rise will we have to endure in the remainder of the 21st century (and beyond). Predictions of future sea level rise should be based on physics, not statistics. Statistics simply doesn’t enable us to foresee the future beyond a very brief window of time. Even given the observed acceleration in the satellite era, the forecasts we should attend to are not from statistics but from physics.

Global geological sea-level data from the Common Era (last 2000 years), global sea-level data from tide gauge records since 1880 and now satellite sea-level data from 1993 all show that the rate of sea level rise is accelerating. These accelerations in sea level is a cause for great concern. As the satellite altimetry record length grows so does the satellite derived time series of (near) global mean sea surface height. Putting recent estimates of GMSL, 2.6-3.2 mm/yr, into historical context is an important and daunting task, and is necessary in order to quantify sea-level accelerations, both regionally and globally. This CNN paper highlights the importance of the Nerem’s excellent paper.

It is accurate to say sea-level rise is approximately one foot per century. Present-day sea-level rise is a major indicator of climate change. Since the early 1990s, sea level rose at a mean rate of ~3.1 mm/yr (~1 foot over 100 years).

It is virtually certain that global mean sea level rise will continue for many centuries beyond 2100, with the amount of rise dependent on future emissions. The IPCC5AR estimates 1 to more than 3 m (up to ~10feet) for high emission scenarios by 2300. But, AR5 projections of sea-level rise may be limited by uncertainties surrounding the response of the Greenland and Antarctic ice sheets. For example, AR5 projected a likely contribution of the Antarctic ice sheet (AIS) of -8 – 15 cm under RCP 8.5 by 2100, but a recent coupled ice sheet and climate dynamics model suggests that the AIS could contribute more than 1 m by 2100, and more than 10 m by 2300, under RCP 8.5.

This statement is supported by peer-reviewed literature. 20th and 21st century rates of relative sea-level rise varied from -4 mm/yr to 3 mm/yr, and are dwarfed by potential future rates of 21st century rise, which under high forcing and unfavorable ice sheet dynamics could exceed 2 m (i.e., a century-average rate of 20 mm/yr) in many locations

The contribution from Greenland (GrIS) and Antarctic (AIS) Ice Sheet mass loss has increased since the early 1990s, comprising ~19% of the total observed rise in GMSL between 1993 and 2010 and ~40% of the total observed rise in GMSL between 2003 and 2008 (Cazenave et al., 2009; Helm et al., 2014). GrIS and AIS contributions are projected to become increasingly important over the 21st century (IPCC, 2013) and dominate sea-level rise uncertainty in the second half of the 21st century (Kopp et al., 2014; Cornford et al., 2015).

Process-based predictions of sea-level rise by the International climate panel (ie the IPCC) are limited by uncertainties surrounding the response of the Greenland and West Antarctic ice sheets (Pfeffer et al., 2008; Pritchard et al., 2012; Rignot et al., 2011), steric changes (Domingues et al., 2008; Marcelja, 2010), contributions from mountain glaciers (Raper and Braithwaite, 2009), as well as from groundwater pumping for irrigation purposes and storage of water in reservoirs (Konikow, 2011; Pokhrel et al., 2012; Wada et al., 2012). In large part because of the limitations of physical process models, IPCC AR5 does not offer “very likely” (5th to 95th percentile) sea-level projections, but concluded that “there is currently insufficient evidence to evaluate the probability of specific levels above the assessed likely range” (Summary for Policy Makers, p. 18).

False. For example, the largest survey ever of the world’s foremost sea-level rise experts shows that a meter of warming is probable by 2100 with unchecked emissions. This was published in a peer-reviewed journal (Horton et al., 2014, Quaternary Science Reviews

False. Comparison of long tide gauge records and multi-centennial to millennial scale sea-level reconstructions from the same region indicates that the rate of rise during the instrumental period (since ~1850 CE) was significantly faster than it was during the late Holocene (the 4000–2000 years prior to ~1850 CE). The data conclude that an acceleration in the rate of sea-level rise occurred,

This could be considered cherry-picking the data. Long-term (>60yrs) tide gauges should be used.

Virginia Key has only been operational since 1994.

Key West Tide gauge has been operational since 1901 and records a rate of sea-level rise of 2.37 mm/yr

The largest change in rate of sea-level rise is between the background pre-industrial period and the 20th century.

Sea-level rose at 1.27 ± 0.09m in northeastern Florida (USA) during the past ~2600 years

The tide-gauge data from nearby Fernandina Beach, measures 1.91 ± 0.26mm/yr of RSL rise since 1900CE.

True: Sea-level rise in Florida is the result of a variety of factors. But the influence of a weakening gulf stream will be felt more in the northeast of the US than Florida. Furthermore, land level subsidence due to glacial isostatic adjustment are less in Florida and the mid and northeast Atlantic.

With respect toe melting from Greenland; yes Florida will have a greater impact that regions to the North. But the rate of rise will be less than the global average