Understanding the Causes and Consequences of Polar Amplification
The Arctic is warming twice as fast as the global average temperature. How these rapid changes will affect the Arctic region is critical to understand, though the significance of this understanding extends beyond the region since changes in the Arctic are increasingly understood to interact with the climate system of the Earth as a whole via atmospheric circulation and ocean currents. In particular, as climate change continues understanding how changes in the Arctic will affect weather and climate of the northern continents is a critical and timely question. Improved understanding of the mechanisms of teleconnection in these systems will shed light on how the Earth’s climate system works as it departs further from the norms of the 20th century. The ability to model these changes has the potential to better describe future climate and its ecological and societal impacts as the century unfolds. To make progress, it is imperative to consider the larger context of the causes and consequences of polar amplification in the global climate system, and examine connections between the faster pace of warming in the polar regions compared to lower latitudes.
The Arctic is warming twice as fast as the global average temperature. With this temperature change, the areal extent and thickness of the polar sea ice is being radically altered. As this process continues, more Arctic Ocean is exposed to direct warming from the sun due to its darkness compared to the reflectivity of sea-ice. In addition, the warmer temperatures are altering high-latitude snow and ice on land, further darkening higher latitudes. How these rapid changes will affect the Arctic region is critical to understand, though the significance of this understanding extends beyond the region since changes in the Arctic are increasingly understood to interact with the climate system of the Earth as a whole via atmospheric circulation and ocean currents. In particular, as climate change continues understanding how changes in the Arctic will affect weather and climate of the northern continents is a critical and timely question. Improved understanding of the mechanisms of teleconnection in these systems will shed light on how the Earth’s climate system works as it departs further from the norms of the 20th century. Patterns of behavior such as the typical position of the jet stream, the shape and persistence of the polar vortex are examples of how an Arctic change may be shown to dramatically affect lower latitude conditions. The ability to model these changes has the potential to better describe future climate and its ecological and societal impacts as the century unfolds.
Much attention has been focused recently on the potential impacts of Arctic sea-ice loss upon mid-latitude weather, with possible significant societal implications. However, this influence does not occur in isolation from the rest of the global coupled climate system and other aspects of human-induced climate change. Indeed, there are vigorous two-way interactions between the tropics and higher latitudes, and other consequences of climate change besides how Arctic sea-ice loss affects mid-latitude weather. To make progress, it is imperative to consider the larger context of the causes and consequences of polar amplification in the global climate system, and examine connections between the faster pace of warming in the polar regions compared to lower latitudes.
This workshop is structured around key scientific questions:
• What are the drivers and mechanisms of polar amplification and its climate effects?
• How do the polar regions communicate with the tropics?
• What is the relative importance of sea-ice loss versus other climate change signals in polar amplification?
• What are the roles of the ocean and stratosphere in driving and responding to polar amplification?
• How do we interpret the short observational record in light of natural variability and forced climate change?
• Do models simulate the correct characteristics and magnitudes of natural variability and response to external forcings?
• What coordinated numerical experiments are needed to make further progress?
Workshop Agenda
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9:20 am Part I: Review, Motivation, and Provocation
9:50 am Review of US CLIVAR Workshop and Findings Presented by Xiangdong Zhang
10:00 am Interactive Responses to Prompts
11:10 am Part II: Causes of Arctic Sea Ice Loss Presented by David Schneider, John C Fyfe, Xiangdong Zhang
11:40 am Ice-Free Arctic Projections Under 1.5 and 2.0°C Stabilized Warming Presented by Michael Sigmond
2:25 pm Part III: Causes of Arctic Amplification Presented by Baek-Min Kim, Paul Joel Kushner, James Screen
2:30 pm Tropically Excited Arctic Warming Mechanism (TEAM): A Theory for Polar Amplification from a General Circulation Perspective Presented by Sukyoung Lee
3:45 pm Polar Amplification Processes and Feedbacks in Response to Individual Climate Forcings Presented by Cecilia Bitz
4:40 pm Poster Session
8:55 am Part III: Causes of Arctic Amplification Presented by Zachary Michael Labe, James Screen, Doug Smith
10:15 am Accelerated Systematic Changes in the Arctic and Intensified Arctic-Midlatitude Linkage Presented by Xiangdong Zhang
11:40 am Part IV: Causes of Antarctic Change Presented by Karen L Smith, Qinghua Ding, Xiangdong Zhang
12:10 pm The enigma of Antarctic temperature trends since the IGY Presented by Lorenzo Polvani
2:25 pm Part V: Consequences of Arctic amplification: modeling results Presented by Yutian Wu, Clara Deser, James Screen
2:55 pm Global Climate Response to Projected Transient Arctic Sea Ice Loss Presented by Lantao Sun
4:10 pm Discussion
Elizabeth Barnes loves noise – atmospheric noise that is. Her passion is sifting through geophysical data in search of previously undetected signals. She gets to do this every day, as well as teach the next generation of scientists techniques for doing so, as an Assistant Professor at Colorado State University. Her research covers a variety of questions related to atmospheric variability, including, “Can we forecast extreme weather 5 weeks in advance?” to “How does the atmosphere respond to volcanic eruptions?” Prof. Barnes and her fantastic research group have written over 40 papers on extracting atmospheric “music” from the “noise” across a range of past, present and future climates.
8:55 am Par V: Consequences of Arctic Amplification: Modeling Results Presented by Elizabeth Barnes, Doug Smith
9:25 am Cold extremes over Eurasia in a grand ensemble of simulations performed with the MPI-Earth System Model Presented by Juergen Bader
11:15 am Part VI: Consequences of Arctic Amplification: Role of the Stratosphere Presented by Qinghua Ding, Lantao Sun, Xiangdong Zhang
11:45 am The Role of Stratospheric Pathway in Linking Barents-Kara Sea Sea Ice to the Midlatitude Circulation Presented by Yutian Wu
8:55 am Part VII: Consequences of Arctic Amplification: Observations and Prediction Presented by Yutian Wu, Gudrun Magnusdottir, James Screen
11:40 am Part VIII: Looking forward: progress in observation and models Presented by Lantao Sun, Thomas Jung, Doug Smith
11:45 am In search of teleconnections forced by Arctic Amplification Presented by Martin Hoerling
Workshop Outcomes
Organizers
Attendees
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