Global sea-level contribution from Arctic land ice: 1971 to 2017

The Arctic Monitoring and Assessment Program (AMAP) (AMAP, 2017) identifies the
Arctic as the largest regional source of land ice to global sea-level rise in the 2003 to 2014
period. Yet, this contextualization ignores the longer perspective from in-situ records of
glacier mass balance. Here, using 18 (> 55 °N latitude) glacier and ice cap mass balance
series in the 1971 to 2017 period, we develop a semi-empirical estimate of annual sealevel
contribution from seven Arctic regions by scaling the in-situ records to GRACE
averages. We contend that our estimate represents the most accurate mass balance
assessment so far available before the 1992 start of satellite altimetry.
We estimate the 1971 to 2017 eustatic sea-level contribution from land ice north of
~55° N to be 23.0±12.3 mm sea-level equivalent (SLE). In all regions, the cumulative sealevel
rise curves exhibit an acceleration, especially after 1988. Greenland is the source of
46% of the Arctic sea-level rise contribution (10.6±7.3 mm), followed by Alaska (5.7±2.2
mm), Arctic Canada (3.2±0.7 mm) and the Russian High Arctic (1.5±0.4 mm).
Our annual results exhibit co-variability over a 43 year overlap (1971 to 2013) with
the alternative dataset of Marzeion et al (2015) (M15). However, we find a 1.36x lower
sea-level contribution, in agreement with satellite gravimetry.
The IPCC Fifth Assessment report identified constraining the pre-satellite era sealevel
budget as a topic of low scientific understanding that we address and specify sealevel
contributions coinciding with IPCC Special Report on the Ocean and Cryosphere in
a Changing Climate (SROCC) “present day” (2005-2015) and “recent past” (1986-2005)
reference periods. We assess an Arctic land ice loss of 8.3 mm SLE during the recent past
and 12.4 mm SLE during the present day.