From the NCA Report:
Note: 2 red lines were added to the graph above from the NCA report. The lower line shows a linear extrapolation of the sea level rise over the past century of 3 - 8 inches per century. Via the report: “Figure shows estimated, observed, and possible amounts of global sea level rise from 1800 to 2100, relative to the year 2000. Estimates from proxy data (for example, based on sediment records) are shown in red (1800-1890, pink band shows uncertainty), tide gauge data in blue for 1880-2009, and satellite observations are shown in green from 1993 to 2012. The future scenarios range from 0.66 feet to 6.6 feet in 2100. These scenarios are not based on climate model simulations [not true], but rather reflect the range of possible scenarios based on other kinds of scientific studies. The orange line at right shows the currently projected range of sea level rise of 1 to 4 feet by 2100, which falls within the larger risk-based scenario range. The large projected range reflects uncertainty about how glaciers and ice sheets will react to the warming ocean, the warming atmosphere, and changing winds and currents. As seen in the observations, there are year-to-year variations in the trend.” (U.S. Global Change Research Program)
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From a tweet today by Steven Goddard |
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From Cazenave et al 2014. Rate of sea level rise has decelerated 31% since 2002. |
References finding either no acceleration or a deceleration of sea level rise during the 20th and 21st centuries:
Chen et al 2013
JM Gregory et al Journal of Climate 2012
M Beenstock et al 2013
NOAA 2005-2012 Sea Level Budget
Dean & Houston 2011 & 2013
Scafetta 2013
Holgate 2007
Boretti 2012
Morner 2004
Jevrejeva et al 2006 & 2008
Wöppelmann et al 2009
Roemmich et al 2013
IPCC 2007:
"no long-term acceleration of sea level has been identified using 20th-century data alone."
IPCC 2013:
"It is likely that GMSL [Global Mean Sea Level] rose between 1920 and 1950 at a rate comparable to that observed between 1993 and 2010"
...the authors find that sea level rise is a localized rather than global phenomenon, with 61 percent of tide gauge records demonstrating no change in sea levels, 4 percent showing a decrease, and a minority of 35 percent showing a rise. This implies relative sea level change is primarily related to subsidence or post-glacial rebound (land height changes) rather than melting ice or steric sea level changes (thermal expansion from warming). Steric sea level rise from thermal expansion turned negative in 2007. Sea levels during the last interglacial were 31 feet higher than the present, and Greenland 8 degrees C warmer than the present, without anthropogenic forcing. There is no evidence suggesting the current interglacial is any different.
but it is continuing to rise ...
ReplyDeleteThat's what happens during interglacials, ice melts and sea level rises naturally until the next glaciation.
DeleteMorner’s latest paper selects a site where there hasn’t been any uplift or subsidence over past 8000 years, finds 0.81 mm/year sea level rise since 1890, with no acceleration:
ReplyDeletehttp://joannenova.com.au/2014/06/sea-level-rise-less-than-1mm-for-last-125-years-nils-axel-morner/