2016: The Climate of Antarctica and the Southern Ocean

Led by Cecilia Bitz, UW Atmospheric Sciences.

74 participants assembled at Friday Harbor Labs in the San Juan Islands for the 15th PCC Summer Institute to discuss the climate of the Antarctic and Southern Ocean. Presentations covered climate processes, current climate change, and paleoclimate records of the past few million years with a focus on better understanding the present-day and future projections.

Andy Thompson, from CalTech, kicked off the SI discussing a cutting edge view of the Southern Ocean as more than a spinning ring around an icy continent. He took us on a tour of the ins and outs of the Antarctic Circumpolar Current and left us with a list of hot topics to ponder. Knut Christianson was next and discussed the fate of the Antarctic ice sheet in a warmer climate. He explained how the first signs of warming are melting at the ice shelves and the speed up of the flow down the Antarctic glaciers.

This year we held a public evening lecture with two speakers. Steve Warren led with a presentation about the Climate of the Antarctic Ice Sheet with a mix of classic hand-drawn sketches, inspiring photographs, and modern scientific graphics. He had us imagining what it would be like to don a meter pile of warm clothes to climb a 32-meter meteorology tower in the dead of winter and experience a 12 degree Celsius temperature inversion. Kyle Armour followed with an engaging explanation of the sea-saw of climate trends in the Arctic and Antarctic. He made a case for the delayed warming in the south from the damping effect of deep ocean waters upwelling around Antarctica.

One of Steve Warren’s hand-drawn sketches!

The next morning David Thompson, from Colorado State University, gave a stirring talk about the atmospheric circulation in the high southern latitudes. He explained new ideas how cloud radiative effects enhance the atmospheric circulation response to global warming. Dargan Frierson was up next with an entertaining talk about why it is cold in the Southern Ocean and how it attracted early explorers. He also showed how the extreme height of the Antarctic ice sheet alters atmospheric circulation in the vicinity, in the tropics, and even in the Arctic. The last speaker of the morning was Lorenzo Polvani, from Columbia University. He spoke about the substantial role of variability in the Antarctic, and made a case that the sea ice expansion of the last 38 years is driven by internal variability.

After an afternoon of community building biking, whale watching, hiking, and above all conversing about climate change, everyone returned for a late afternoon poster viewing and evening talks. Curtis Deutsch spoke first about the outsized role of the Southern Ocean in the global carbon cycle. Next, Amelia Shevenell, from University of South Florida, captivated us with her description of the paleoclimate proxies from Antarctica, and their importance for deciphering the climate change of the past.

The final session began with Michell Koutnik speaking about Holocene climate change and the ice accumulation changes seen in ice-core records and ice layer dynamics visualized with ground-penetrating radar. In a step further back, Louise Sime, from the British Antarctic Survey, told us about the Last Interglacial (LI) climate that is understood from ice coring campaigns and from clever modeling studies. She gave a convincing case for the West Antarctic Ice Sheet collapse during the LI. The institute was capped off by Eric Steig, who drew connections between the climate of the past seen in Antarctic ice cores and the climate change and variability we are experiencing today.

– Cecilia Bitz, Atmospheric Sciences, convener of the 2016 PCC Summer Institute

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