Evidence for the accelerations of sea level on multi‐decade and century timescales

Abstract

ABSTRACT:A modification in the rate of change of sea level (i.e. an 'acceleration' or 'nonlinear trend') is an important climate-related signal, which requires confirmation and explanation. In this study, the evidence for accelerations in regional and global average sea level on timescales of several decades and longer is reviewed by inter-comparison of the recent findings of different researchers and by inspection of original tide gauge records. Most sea-level data originate from Europe and North America, and both the sets display evidence for a positive acceleration, or 'inflexion', around 1920-1930 and a negative one around 1960. These inflexions are the main contributors to reported accelerations since the late 19th century, and to decelerations during the mid-to late 20th century. However, these characteristic features are not always found in records from other parts of the world. Although some aspects of the sea-level time series are consistent with changes in rates of globally averaged temperature changes, volcanic eruptions and natural climate variability, modelling undertaken so far has been unable to describe these features adequately. This emphasizes the need for a major enhancement of the sea-level data set, especially for those parts of the world without long tide gauge records, in order to obtain greater insight into the spatial dependence of accelerations. A number of complementary methods must be employed, of which salt marsh techniques offer the possibility of obtaining time series similar to those that would have been obtained from coastal tide gauges.

Quantifying the Contribution of Sediment Compaction to late Holocene Salt-Marsh Sea-Level Reconstructions, North Carolina, USA

“…The decompacted rate of sea-level rise since ~AD 1850 (1.71 mm yr -1 ) approximates rates observed over similar timeframes in regional (Zervas, 2004) and globally-averaged (Douglas, 1991;Church and White, 2006;Jevrejeva et al, 2008;Church and White, 2011;Woodworth et al, 2009) tide-gauge records. This agreement is of interest because the North Carolina late…”

Sea-Level Rise from the Late 19th to the Early 21st Century

“…Many previous studies have used the individual sealevel records (corrected for vertical land motion) to estimate the local rate of sea-level rise (as a linear trend; e.g. Douglas 1991) and some studies attempted to detect an acceleration in the local rate of sea-level rise (Woodworth 1990;Woodworth et al 2009;Douglas 1992). However, these individual records have considerable interannual and decadal variability and thus long records are required to get accurate estimates of the local trends in sea level (Douglas 2001).…”

Nonlinear subsidence at Fremantle, a long‐recording tide gauge in the Southern Hemisphere

“…For example, the vertical stability of the Australian continent and its suitability as a datum for MSL observations has been debated for decades [e.g., Emery, 1986, 1988;Bryant et al, 1988;Amin, 1993;Belperio, 1993;Feng et al, 2004;Sandiford, 2007;Moucha et al, 2008;Watson, 2011;Lewis et al, 2012]. Hay et al [2015], Haigh et al [2014], Hogarth [2014], Holgate and Woodworth [2004], Jevrejeva et al [2014], Jorda [2014], Merrifield et al [2009], Olivieri and Spada [2013], Watson et al [2015], and Woodworth et al [2009Woodworth et al [ , 2011; those that claim deceleration include Boretti [2012], Boretti and Watson [2012], Parker et al [2013], and Watson [2011]; those that claim neither include Schr€ oter [2010, 2014].…”