Senator Ian Macdonald asked the Minister representing the Minister for Climate Change and Energy Efficiency, upon notice, on 6 October 2011: (1) What percentage of the atmosphere is composed of carbon dioxide. (2) What percentage of the total carbon dioxide is of human-related origin. (3) What percentage of the human-related carbon dioxide is sourced from Australia. (4) How much global warming, in degrees Celsius, will be averted should Australia reduce its carbon dioxide emissions by 5 per cent by 2020. (5) What will be the total cost by 2020, and the cost per family of four persons, the government policies that are intended to effect the 5 per cent reduction.