65 J.M. Grebmeier and W. Maslowski (eds.), The Pacific Arctic Region: Ecosystem Status and Trends in a Rapidly Changing Environment, DOI 10.1007/978-94-017-8863-2_4, © Springer Science+Business Media Dordrecht 2014 Abstract The purpose of this chapter is to reveal several emerging physical ice-ocean processes associated with the unprecedented sea ice retreat in the Pacific Arctic Region (PAR). These processes are closely interconnected under the scenario of diminishing sea ice, resulting in many detectable changes from physical environ- Chapter 4 Abrupt Climate Changes and Emerging Ice-Ocean Processes in the Pacific Arctic Region and the Bering Sea Jia Wang, Hajo Eicken, Yanling Yu, Xuezhi Bai, Jinlun Zhang, Haoguo Hu, Dao-Ru Wang, Moto Ikeda, Kohei Mizobata, and James E. Overland J. Wang (*) Great Lakes Environmental Research Laboratory (GLERL), National Oceanic and Atmospheric Administration, Ann Arbor, MI, USA e-mail: jia.wang@noaa.gov H. Eicken Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK, USA Y. Yu Arctic Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA, USA J. Zhang Applied Physics Laboratory, University of Washington, Seattle, WA, USA X. Bai • H. Hu Cooperative Institute for Limnology and Ecosystems Research (CILER), School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI, USA D.-R. Wang Hainan Marine Development and Design Institute, Hainan, China M. Ikeda Graduate School of Earth and Environmental Sciences, Hokkaido University, Sapporo, Japan K. Mizobata Department of Ocean Sciences, Tokyo University of Marine Science and Technology, Tokyo, Japan J.E. Overland Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration, 7600 Sand Point Way NE, Seattle, WA 98115, USA