The Canadian Meteorological and Oceanographic Society (CMOS) is the national society of individuals and organisations dedicated to advancing atmospheric and oceanic sciences and related environmental disciplines in Canada. CMOS has more than 800 members from Canada’s major research centres, universities, private corporations and government institutes. CMOS is uniquely positioned to provide expert advice to Canadians on the science of climate change. Many of its members are internationally recognized scientific experts who are extensively involved in comprehensive assessments of the current state of knowledge with respect to this complex issue. Such assessments require atmospheric and ocean scientists working together with scientists in related environmental, social and economic disciplines.