Geoscience Reference
In-Depth Information
6.4 General Discussion
The review of literature and analysis in this paper confirms a picture of advances in our
knowledge about the Arctic water environment and its functioning during recent decades.
Climate model advances have improved in precision and alignment with observations in
the Arctic, and numerous studies have contributed to a fuller understanding of hydro-
climatic changes. International efforts at making discharge information accessible, e.g.,
through the ArcticRIMS project, have contributed to a more timely access to river flow
data for a number of the major Arctic basins and sub-basins. Similarly, the PARTNERS
monitoring campaign (
http://ecosystems.mbl.edu/partners
), now semi-permanently estab-
lished as the Arctic Great Rivers Observatory (
http://www.arcticgreatrivers.org
), has
provided a multi-season data set of concentrations of a range of biogeochemical water
chemistry constituents for six major Arctic rivers. These developments, which coincide in
time with a growing focus on the Arctic as a place of large-scale geophysical and geo-
political changes, imply that our ability to understand the AHC has increased.
Nevertheless, considerable challenges for understanding and managing the rapidly
changing Arctic water system still remain. A critical priority must be to continue
improving the accessibility to water data, in particular for water chemistry, for the PADB.
Observations must be made at well-chosen places, with the choices and improvements
being based on clearly stated information goals, striving in their achievement for win-win
and no-regret approaches that do not rely on some single, most likely model scenario of
future hydro-climatic conditions. Improved coverage of unmonitored areas in the northern
rims of the PADB is also motivated, particularly as these areas are expected to become
increasingly accessible and also subject to exploration with a warming climate (Andreeva
1998
). In addition, improved monitoring here may provide better insight into the total flux
of water constituents to the ocean from these areas, as near-ocean catchments have in other
regions been shown to contribute a disproportionately large share of coastal pollution in
relation to the drainage basin as a whole (Destouni et al.
2008
).
7 Conclusions
In this paper, we have synthesized and investigated climate model projections, hydro-
climatic change understanding and adequacy of water flow and water chemistry obser-
vations in the PADB. The purpose has been to establish a quantitative picture of the status
of model results, hydro-climatic links and observations needed to understand and manage
water cycle changes in the Arctic. The main findings of the paper can be summarized in the
following conclusions:
•
The precision in climate model projection of precipitation and temperature change on
drainage basin scales has improved between successive generations of the IPCC model
ensemble. Individual model performance varies greatly, and models can be right for the
wrong reasons when relatively large errors cancel out on large basin scales for some
models. Further investigation and benchmarking of model performance in the GCMs
that underlie the IPCC AR5 will show whether certain hydro-climatological model
shortcomings in the Arctic have been addressed.
•
From the investigation into geographical consistency in the relative distribution of
climate deviations and changes, it follows that establishing regional priorities for
hydrological monitoring systems, with regard to the specific issue of climate changes in
