As a follow-up to my last post (Reply #483), it is important to note that trends in insolation related Antarctic sea ice (and it is not clear to me that Steven's extension of Tamino's work correctly captures the timing differences between when the sea ice is present and when the solar irradiance is occurring) is only one transient consideration. Other considerations include: (a) the influence of polar amplification on climate sensitivity (ie what ever difference in Arctic vs Antarctic sea ice insolation trends that there is, polar amplification will make this difference about three times more important to mean global warming); (b) the influence of CO₂ venting on the net amount of CO₂ absorbed by the Southern Ocean and (c) the recent, and likely to continue, slow-down of Antarctic Bottom Water, AABW, production which will likely slow the future rate of heat absorption by the ocean.
In this regards, the first linked reference (with a free pdf by Armour et al 2014), indicates that heat input directly into the high latitudes, is about three times more effective at promoting mean global temperature rise, than an equal heat input into the tropics. This polar amplification emphasizes the importance of the Southern Ocean venting (see the second linked reference by Quere et al 2007) CO₂ directly into the high latitude Southern Atmosphere, as well as the reduce OHU in the Southern Ocean due to the slow-down in the AABW production rate:
Rose, B. E. J., K. C. Armour, D. S., Battisti, N. Feldl, and D. D. B. Koll, (2014)," The dependence of transient climate sensitivity and radiative feedbacks on the spatial pattern of ocean heat uptake", Geophys. Res. Lett., 41, doi:10.1002/2013GL058955.
http://web.mit.edu/karmour/www/Rose_etal_GRL2014.pdfAbstract: "The effect of ocean heat uptake (OHU) on transient global warming is studied in a multimodel framework. Simple heat sinks are prescribed in shallow aquaplanet ocean mixed layers underlying atmospheric general circulation models independently and combined with CO2 forcing. Sinks are localized to either tropical or high latitudes, representing distinct modes of OHU found in coupled simulations. Tropical OHU produces modest cooling at all latitudes, offsetting only a fraction of CO2 warming. High latitude OHU produces three times more global mean cooling in a strongly polar-amplified pattern. Global sensitivities in each scenario are set primarily by large differences in local shortwave cloud feedbacks, robust across models. Differences in atmospheric energy transport set the pattern of temperature change. Results imply that global and regional warming rates depend sensitively on regional ocean processes setting the OHU pattern, and that equilibrium climate sensitivity cannot be reliably estimated from transient observations."
The first attached image by Le Quere shows her original field data compared to the previously expected CO₂ absorption projections for the Southern Ocean (see the caption below). The second image shows the increase in the wind velocities, primary due to the ozone hole.
Corinne Le Quéré, Christian Rödenbeck, Erik T. Buitenhuis, Thomas J. Conway, Ray Langenfelds, Antony Gomez, Casper Labuschagne, Michel Ramonet, Takakiyo Nakazawa, Nicolas Metzl, Nathan Gillett, Martin Heimann, (2007),"Saturation of the Southern Ocean CO₂ Sink Due to Recent Climate Change", Science, Vol. 316, no. 5832 pp. 1735-1738, DOI: 10.1126/science.1136188
http://www.cccma.ec.gc.ca/papers/ngillett/PDFS/1735.pdfhttp://www.sciencemag.org/content/316/5832/1735Abstract: "Based on observed atmospheric carbon dioxide (CO2) concentration and an inverse method, we estimate that the Southern Ocean sink of CO2 has weakened between 1981 and 2004 by 0.08 petagrams of carbon per year per decade relative to the trend expected from the large increase in atmospheric CO2. We attribute this weakening to the observed increase in Southern Ocean winds resulting from human activities, which is projected to continue in the future. Consequences include a reduction of the efficiency of the Southern Ocean sink of CO2 in the short term (about 25 years) and possibly a higher level of stabilization of atmospheric CO2 on a multicentury time scale."
Caption for the first image: " Le Quéré expected to see a steady increase in the amount of carbon dioxide absorbed by the Southern Ocean between 1981 and 2004 (blue line). Instead, weather station measurements (red line) suggested year-to-year variability, but no long-term increase over time. (Graph by Corrine Le Quéré, University of East Anglia.)"
See also the "Southern Ocean Venting of CO₂" thread:
http://forum.arctic-sea-ice.net/index.php/topic,888.0.htmlEdit: The devil is in the detail and it is essential that models be improved to capture all such key Antarctic and global feedback mechanisms.