as a result, attention was deflected away from References the hard work of hundreds of scientists. Even to this day, many scientists cite ACIA 2004, not ACIA 2005. Furthermore, there was confusion over the authorship of the technical report, and many different citations can be found in the literature. For 1 Huntington, H., T.V. Callaghan, S.H. Fox, and I. Krupnik (2004). Matching Traditional and Scientific Observations to Detect Environmental Change: A Discussion on Arctic Terrestrial Ecosystems. Ambio Special Report 13: 18-23. example, some citations give the overall reviewers 2 the distinction of authors or editors. Fortunately, H. Marchant, T.D. Prowse, H. Vilhja´lmsson, and J.E. Walsh lessons have been learned and the excellent sci- (2007). ‘Polar Regions (Arctic and Antarctic),’ in M.L. Par- ence dominates. ry, O.F. Canziani, J.P. Palutikof, P.J van der Linden, and C.E. What has changed in the science? The ACIA findings, often including predictions based on first principles, are still highly relevant and are often cited. Anisimov, O.A., D.G. Vaughan, T.V. Callaghan, C. Furgal, Hanson, eds., Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of working group II to the fourth assessment report of the intergovernmental panel on climate change. Cambridge, UK: Cambridge University Press. Many of the predictions published in 2005 are now being confirmed by observation. However, a better understanding of variability—in processes in space and time—has become apparent since ACIA. More intense and more frequent extreme events such as mid-winter thaws, and tundra fires are being recorded, and there is a growing realization that biological processes such as the greening of the Arctic vary from location to location and even within catchments. There is also growing awareness that the impacts of increased UV-B radiation in the Arctic are less dramatic than many impacts of climate warming. ACIA developed a successful scaling approach, from circumarctic models, through regional assessments, to local case studies, and this was an important development for current down-scaling studies to provide detailed predictions of climate change and its impacts at scales appropriate for the development of adaptation strategies by Arctic residents. ACIA is a great credit to IASC, the Arctic Council, the ACIA Coordinator and his team, and all the participants. Its legacy is already immense and will continue to grow. Drafting personal perspectives and recollections of the process and working with IASC and AMAP has been an honor. In summary, it was noted by many that ACIA was the first comprehensive researched, fully referenced, and independently reviewed evaluation of Arctic climate change and its impacts for the region and the world. 50 00 02 IASC Initiatives 3 ACIA (2005). Arctic Climate Impact Assessment. Cam- bridge, UK: Cambridge University Press, 1042p. 4 Hassol, S.J. (2004). Impacts of a Warming Arctic. Cam- bridge, UK: Cambridge University Press, 139p.