It was a great honour for Australia and Hobart to host 200 scientists from around the world in January for the fifth meeting of Working Group 1 Lead Authors for the Intergovernmental Panel on Climate Change’s 5th Assessment Report.  Working Group 1 is responsible for assessing the physical scientific aspects of the climate system and climate change and weighs the evidence in the scientific literature for climate change. They assess evidence for, among other things, changes in greenhouse gases and aerosols in the atmosphere; changes in atmospheric, land and ocean temperatures; changes in global rainfall patterns; changes in ice sheets, glaciers and sea-ice; changes in sea level and physical ocean changes; changes in the global carbon cycle and carbon in the atmosphere, on land and in the oceans; biogeochemistry; and historical and palaeoclimatic aspects of climate change. Working Group I is also responsible assessing outputs from models, providing climate projections and for assessing the evidence for attribution of the causes of climate change. The output of Working Group I underpins global understanding of climate change, and global responses to it. Its considerations are long and in-depth and its processes are thorough and rigorous. We look forward to the IPCC’s Fifth Assessment Report. 2012 was a very successful year at ACE, with the SIPEX-II sea ice voyage one of many highlights. On their return in November the expeditioners had spent 63 days at sea. Fifty scientists from nine countries and the crew of Aurora Australis spent 49 days in the Antarctic sea ice unravelling the secrets it holds for the global climate system and the for Antarctic ecosystems. This edition of the ACE Newsletter contains many stories from this epic research voyage. I do hope you enjoy reading about this voyage and our other work. 2013 will be the final year for the ACE CRC as we currently know it.  We have much to complete in all our programs – carbon, cryosphere, oceans, ecosystems impacts and sea-level rise impacts - and look forward to the contribution that this work will make to our future understanding of the role Antarctica and the Southern Ocean play in the global climate. Tony Press

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