Global sea level trend during 1993–2012

Abstract

Projection of future sea level change relies on the understanding of present sea-level trend and how it has varied in the past. Here we investigate the global-mean sea level (GMSL) change during 1993–2012 using Empirical Mode Decomposition, in an attempt to distinguish the trend over this period from the interannual variability. It is found that the GMSL rises with the rate of 3.2±0.4mm/yr during 1993–2003 and started decelerating since 2004 to a rate of 1.8±0.9mm/yr in 2012. This deceleration is mainly due to the slowdown of ocean thermal expansion in the Pacific during the last decade, as a part of the Pacific decadal-scale variability, while the land-ice melting is accelerating the rise of the global ocean mass-equivalent sea level. Recent rapid recovery of the rising GMSL from its dramatic drop during the 2011 La Niña introduced a large uncertainty in the estimation of the sea level trend, but the decelerated rise of the GMSL appears to be intact.