This is the final version of the article. Available from the publisher via the DOI in this record.Numerous components of the Arctic freshwater system (atmosphere, ocean, cryosphere, and terrestrial hydrology) have experienced large changes over the past few decades, and these changes are projected to amplify further in the future. Observations are particularly sparse, in both time and space, in the polar regions. Hence, modeling systems have been widely used and are a powerful tool to gain understanding on the functioning of the Arctic freshwater system and its integration within the global Earth system and climate. Here we present a review of modeling studies addressing some aspect of the Arctic freshwater system. Through illustrative examples, we point out the value of using a hierarchy of models with increasing complexity and component interactions, in order to dismantle the important processes at play for the variability and changes of the different components of the Arctic freshwater system and the interplay between them. We discuss past and projected changes for the Arctic freshwater system and explore the sources of uncertainty associated with these model results. We further elaborate on some missing processes that should be included in future generations of Earth system models and highlight the importance of better quantification and understanding of natural variability, among other factors, for improved predictions of Arctic freshwater system change.The first two authors have contributed
equally to the publication. The Arctic
Freshwater Synthesis has been
sponsored by the World Climate
Research Programme’s Climate and the
Cryosphere project (WCRP-CliC), the
International Arctic Science Committee
(IASC), and the Arctic Monitoring and
Assessment Programme (AMAP). C.L.
acknowledges support from the UK
Natural Environment Research Council.
M.M.H. acknowledges support from NSF
PLR-1417642. D.M.L. is supported by
funding from the U.S. Department of
Energy BER, as part of its Climate Change
Prediction Program, Cooperative
Agreement DE-FC03-97ER62402/A010,
and NSF grants AGS-1048996,
PLS-1048987, and PLS-1304220. J.A.S. is
supported by Natural Environment
Research Council grant NE/J019585/1.
Y.D. is supported by Environment
Canada’s Northern Hydrology program.
We acknowledge the World Climate
Research Programme’s Working Group
on Coupled Modelling, which is responsible
for CMIP, and we thank the climate
modeling groups for producing and
making available their model output. For
CMIP, the U.S. Department of Energy’s
Program for Climate Model Diagnosis
and Intercomparison provides
coordinating support and led
development of software infrastructure
in partnership with the Global
Organization for Earth System Science
Portals. The CMIP data and CESM-LE data
are available through the relevant Web
data portal
