1. The Future of Arctic Sea Ice Authors: Wieslaw Maslowski, Jaclyn Clement Kinney, Matthew Higgins, and Andrew Roberts Brian Rosa – Atmospheric Sciences

2. Statistics on Arctic Sea Ice Record minimum ice cover in 2007 Arctic sea ice is declining on average Not only is ice extent down but so is thickness and volume Arctic ice extent taken in March 2015 shows lowest ice extent in history for the month of March

3. 2007 Record September low

4. Arctic sea ice effects on global climate Sea ice cover buffers air-sea heat fluxes Ice albedo strongly influences Earth’s absorption of solar radiation Accelerated melting of Arctic sea ice has effects on atmospheric and oceanic circulation, the Greenland ice sheet, snow cover, permafrost, and vegetation

5. Reduced arctic sea Ice effects Global sea level Ocean thermohaline circulation Effect global surface energy and moisture budgets Geosphere- bioshpere feedbacks

6. Shows little change in sea ice volume from 1980 through mid-1990s in contrast to the later times of 1995-2004 (ON) October - November

7. No Models to predict future trends! To better understand past and present states and estimate future trajectories of Arctic sea ice and climate we need to advance our climate modeling GCMs do not have a high enough resolution and a regional model is needed

8. Model differences in summer Arctic sea ice extent GCMs in ACIA predicts a 50% reduction by the end of the century CMIP2 predicts a little over 10% reduction Models at IPCC AR4 and in CMIP3 suggest an almost ice free Arctic Ocean in the summer by the end of the century The majority of GCMs are not even able to reproduce multidecadal sea ice variability There is no consistency between models

9. Differences in ice thickness between 1997 and 2003 between 2 NCAR ensemble runs and NPS NAME The CCSM4 does not show the over all thinning of sea ice Shows the inability of climate models to properly reproduce the recent states and trends of Arctic sea ice

10. Purpose Stress the need for a hierarchical modeling approach to advance simulations of future Arctic sea ice. Hierarchical modeling – the combined use of GCMs with regional modeling tools and expertise to help understand uncertainty and improve the quality of probabilistic projections

11. Why is it so important? The reduction of Arctic sea ice is a good indicator of climate change Declining sea ice will result in an increase in both frequency and intensity of cyclonic and anticyclonic synoptic – scale systems

12. Model limitations Ocean eddies, tides, fronts, buoyancy-driven costal and boundary currents, cold halocline, dense water plumes and convection, double diffusion, surface mixed layer, sea ice- thickness distribution, concentration, deformation, drift and export, fast ice, snow cover, melt ponds and surface albedo, atmospheric loading, ice sheets and mountain glaciers, permafrost, river runoff, and air-sea ice-land interactions and coupling.

13. Why so tough? Finding the sources of simulation uncertainty is tough because polar systems are incredibly complex and there are so many factors to take into account

14. Model Improvements Starting to include false bottoms Working to include melt ponds

15. Transition from Global Climate Modeling Work is under way to improve fidelity and number of polar-centric processes represented within earth system models, refine coupling channels between them, and expand the hierarchy of available models The need for an Arctic system model (ASM) is being pushed

16. Boundary for ASM, Smaller domain Means higher resolution

17. Headed in the right direction! Currently the US are working towards creating a RASM (Regional Arctic System Model) The RASM is to focus on three main things – Changes in fresh water flux – Changes in energies – The role of small-scale atmospheric and oceanic processes

18. Summary Sea ice is undergoing rapid decline, yet a system level understanding of critical arctic processes and feedbacks are still lacking. Arctic sea ice is a major factor in the global climate system Model limitations are hindering our ability to predict the future state of arctic ice Some work is being done to create a RASM which will ultimately have a high special resolution (5- 50 times higher then currently practical in global models)

19. Since this paper there is an RASM Great improvements expected by coupling more models together