New paper finds global sea levels rose < 7 inches during 20th century, with no acceleration

A paper published today in the Journal of Geophysical Research Oceans finds global sea level rise during the 20th century was only 1.77 mm/yr or 6.96 inches per century, and with no statistically significant acceleration.

The paper joins many other papers finding global sea level rise of less than seven inches per century, with no acceleration. In fact, at least two recent papers find significant decelerations of sea level rise during the 21st century "pause" in global warming, a deceleration of 31% since 2002 and deceleration of 44% since 2004 to less than 7 inches per century. There is no evidence of an acceleration of sea level rise, and therefore no evidence of any effect of mankind on sea levels. Sea level rise is primarily a local phenomenon related to land subsidence, not CO2 levels. 

No statistically significant acceleration. Source from a prior paper of the authors below

Reconstructed sea level trends. Note in bottom graph, sea levels dropped along much of the west coast of North and South America between 1955-2009. Source from a prior paper of the authors below

Global and regional sea level change during the 20th century

Manfred Wenzel and Jens Schröter

Sea level variations prior to the launch of satellite altimeters are estimated by analysing historic tide gauge records. Recently, a number of groups have reconstructed sea level by applying EOF techniques to fill missing observations. We complement this study with alternative methods. In a first step gaps in 178 records of sea level change are filled using the pattern recognition capabilities of artificial neural networks. Afterwards satellite altimetry is used to extrapolate local sea level change to global fields. Patterns of sea level change are compared to prior studies. Global mean sea level change since 1900 is found to be 1.77 ± 0.38 mm year−1 on average. Local trends are essentially positive with the highest values found in the western tropical Pacific and in the Indian Ocean east of Madagascar where it reaches about +6 mm year−1. Regions with negative trends are spotty with a minimum value of about −2 mm year−1 south of the Aleutian Islands. Although the acceleration found for the global mean, +0.0042 ± 0.0092 mm year−2, is not significant, local values range from −0.1 mm year−2 in the central Indian Ocean to +0.1 mm year−2 in the western tropical Pacific and east of Japan. These extrema are associated with patterns of sea level change that differ significantly from the first half of the analyzed period (i.e. 1900 to 1950) to the second half (1950 to 2000). We take this as an indication of long period oceanic processes that are superimposed to the general sea level rise.