title: Reconciling past changes in Earth's rotation with 20th century global sea-level rise: Resolving Munk's enigma.
abstract: In 2002, Munk defined an important enigma of 20th century global mean sea-level (GMSL) rise that has yet to be resolved. First, he listed three canonical observations related to Earth's rotation [(i) the slowing of Earth's rotation rate over the last three millennia inferred from ancient eclipse observations, and changes in the (ii) amplitude and (iii) orientation of Earth's rotation vector over the last century estimated from geodetic and astronomic measurements] and argued that they could all be fit by a model of ongoing glacial isostatic adjustment (GIA) associated with the last ice age. Second, he demonstrated that prevailing estimates of the 20th century GMSL rise (~1.5 to 2.0 mm/year), after correction for the maximum signal from ocean thermal expansion, implied mass flux from ice sheets and glaciers at a level that would grossly misfit the residual GIA-corrected observations of Earth's rotation. We demonstrate that the combination of lower estimates of the 20th century GMSL rise (up to 1990) improved modeling of the GIA process and that the correction of the eclipse record for a signal due to angular momentum exchange between the fluid outer core and the mantle reconciles all three Earth rotation observations. This resolution adds confidence to recent estimates of individual contributions to 20th century sea-level change and to projections of GMSL rise to the end of the 21st century based on them.
authors.affiliation: Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA.
authors.forename: Jerry X
authors.initials: JX
authors.lastname: Mitrovica
authors.affiliation: Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA.; Department of Earth and Planetary Sciences and Institute of Earth, Ocean, and Atmospheric Sciences, Rutgers University, Piscataway, NJ 08854, USA.
authors.forename: Carling C
authors.initials: CC
authors.lastname: Hay
authors.affiliation: Department of Earth and Planetary Sciences and Institute of Earth, Ocean, and Atmospheric Sciences, Rutgers University, Piscataway, NJ 08854, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Morrow
authors.affiliation: Department of Earth and Planetary Sciences and Institute of Earth, Ocean, and Atmospheric Sciences, Rutgers University, Piscataway, NJ 08854, USA.; Rutgers Energy Institute, Rutgers University, Piscataway, NJ 08854, USA.
authors.forename: Robert E
authors.identifier: 0000-0003-4016-9428
authors.initials: RE
authors.lastname: Kopp
authors.affiliation: Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1, Canada.; ISTerre, Université Grenoble Alpes, F-38041 Grenoble, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Dumberry
authors.affiliation: Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada.
authors.forename: Sabine
authors.initials: S
authors.lastname: Stanley
keywords: Climate change; Earth rotation; Earth sciences; sea level
references.citation: Proc Natl Acad Sci U S A. 2002 May 14;99(10):6550-5
references.pmid: 12011419
references.citation: Nature. 2015 Jan 22;517(7535):481-4
references.pmid: 25629092