Climate change has become a major issue in Australia. Since the beginning of the 20th century Australia has experienced an increase of nearly 1 °C in average annual temperatures, with warming occurring at twice the rate over the past 50 years than in the previous 50 years. Recent climate events such as extremely high temperatures and widespread drought have focused government and public attention on the impacts of climate change in Australia. Rainfall in Australia has increased slightly over the past century, although there is little or no trend in rainfall in the Western Plateau and the Central Lowlands of Australia. Water sources in the southeastern areas of Australia have depleted due to increasing population in urban areas (rising demand) coupled with climate change factors such as persistent prolonged drought (diminishing supply). At the same time, Australia continues to have the highest per capita greenhouse gas emissions. Temperatures in Australia have also risen dramatically since 1910 and nights have become warmer. A carbon tax was introduced in 2011 by the Gillard government in an effort to reduce the impact of climate change and despite criticism, it has significantly reduced Australia's carbon dioxide emissions, with coal generation down 11% since 2008-09. The Australian Government under Prime Minister Tony Abbott has been criticised for being "in complete denial about climate change".