Received: 29 Jan 2016 – Discussion started: 02 Mar 2016
Abstract. Following the 2015 UNFCCC Conference of Parties in Paris there is renewed interest in understanding and avoiding potentially dangerous climate change. The loss of Arctic sea ice is one of the most directly visible aspects of climate change and the question is frequently asked: when can we expect the Arctic to be ice-free in summer? We argue here that this question may not be the most useful one to inform decisions on climate change mitigation or adaptation in the Arctic. The development of a community-wide consensus on a robust definition of "ice-free", may reduce confusion in the community and amongst the public.
How to cite. Ridley, J. K., Wood, R. A., Keen, A. B., Blockley, E., and Lowe, J. A.: Brief Communication: Does it matter exactly when the Arctic will become ice-free?, The Cryosphere Discuss. [preprint], https://doi.org/10.5194/tc-2016-28, in review, 2016.
The internal variability in model projections of Arctic sea ice extent is high. As a consequence an ensemble of projections from a single model can show considerable scatter in the range of dates for an "ice-free" Arctic. This paper investigates if the scatter can be reduced for a variety of definitions of "ice-free". Daily GCM data reveals that only a high emissions scenario results in the optimal definition of five conservative years in with ice extent is below one million square kilometer.
The internal variability in model projections of Arctic sea ice extent is high. As a consequence...