This file picture shows an enormous iceberg (R) breaking off the Knox Coast in the Australian Antarctic Territory on January 11, 2008. A UN panel said on 27 September 2013 it was more certain than ever that humans were causing global warming and predicted temperatures would rise by 0.3 to 4.8 degrees Celsius (0.5-8.6 degrees Fahrenheit) this century. AFP PHOTO/POOL/Torsten BLACKWOOD (Photo credit should read TORSTEN BLACKWOOD/AFP/Getty Images)