04/09/2012
Bering Strait May Limit Abrupt Climate Change Due to Ocean Circulation Instability
Summary
The Atlantic Meridional Overturning Circulation (AMOC) acts as a heat conveyer belt, bringing warm tropical water northward in the Atlantic Ocean and carrying cold dense water back southward. Previous model studies suggest that AMOC can trigger abrupt climate change when runoff from melting ice sheet water is added into the North Atlantic. DOE-funded scientists have investigated the role of the Bering Strait (the 50-mile-wide gateway between the Atlantic and Pacific oceans) in abrupt climate change using computationally intensive simulations. They find that as long as the Bering Strait remains open, abrupt climate changes driven by ocean circulation are unlikely. Such climate instabilities occurred frequently during the last glacial period, ranging from 80,000 to 11,000 years ago. Increased freshwater in the North Atlantic would weaken the AMOC, altering the transport of heat and salinity between the Atlantic and Pacific. The study suggests that as long as the Bering Strait remains open, AMOC will likely not exhibit this chain of events. The study reveals how a relatively small geographic feature could have potentially far-reaching impacts and may have influenced global climate patterns over the past 100,000 years, according to the authors.
References
Hu, A., G. A. Meehl, W. Han, A. Timmermann, B. Otto-Bliesner, Z. Liu, W. M. Washington, W. Large, A. Abe-Ouchi, M. Kimoto, K. Lambeck, and B. Wu. 2012. “Role of the Bering Strait on the Hysteresis of the Ocean Conveyor Belt Circulation and Glacial Climate Stability,” Proceedings of the National Academy of Sciences 109(17), 6417-22. DOI: 10.1073/pnas.1116014109.