that the world's climate is warming and that increasing levels of carbon pollution risk environmental and economic damage. Cutting carbon pollution will lower the risks and help ensure our future prosperity -- but the next 10 years are critical. The economic costs of inaction are larger than the costs of tackling climate change. 1.1 Climate change is real The Australian Government has a comprehensive plan for a clean energy future. This plan has been devised in response to clear scientific advice that climate change is happening, is almost certainly caused by increasing carbon pollution from human activity and presents a real threat toour environment and way of life. In Australia and across the globe, 2001 to 2010 was the warmest decade on record (Figure1.1). Each decade in Australia since the 1940s has been warmer than the last. 1.2 Human activity is contributing Greenhouse gases in the atmosphere trap radiation given off by the Earth (Figure 1.2). This helps keep the planet warm enough to sustain life. Since the Industrial Revolution, however, the amount of greenhouse gases in the atmosphere has risen significantly. The rising concentrations of greenhouse gases,like carbon dioxide, cause the atmosphere and the Earth's surface to heat up. Scientists have estimated that humans are responsible for nearly a third of the carbon dioxide now in the atmosphere. It is beyond reasonable doubt that human activities -- the burning of fossil fuels and deforestation -- are triggering the changes we are witnessing in the global climate (Climate Commission, The