"Climate change is one of the defining issues of our time. It is now more certain than ever, based on many lines of evidence, that humans are changing Earth's climate. The atmosphere and oceans have warmed, accompanied by sea-level rise, a strong decline in Arctic sea ice, and other climate-related changes." -- Sir Paul Nurse, President of the Royal Society, and Dr Ralph J Cicerone, President of the US National Academy of Sciences. This panel discussion was held to coincide with the release of a joint publication by the Royal Society and the US National Academy of Sciences: 'Climate Change: Evidence & Causes'. Thursday 27 February 2014 3:00pm - 4:30pm GMT, at the US National Academy of Sciences. Hosted by Miles O'Brien, science correspondent, PBS Newshour Introductions by Dr. Ralph J. Cicerone and Sir Paul Nurse Featuring: Dr. Ralph J. Cicerone, President of the National Academy of Sciences and Sir Paul Nurse, President of the Royal Society gave brief introductions. Host Miles O'Brien guided the discussion with lead authors, Professor Eric Wolff FRS of the University of Cambridge, and Professor Inez Fung of the University of California, Berkeley. The document presents a description of the science of climate change for anyone who is interested to find out more: royalsociety.org/policy/projects/climate-evidence-causes/