Climate change is a global problem. The planet is warming because of the growing level of greenhouse gas emissions from human activity. If this trend continues, truly catastrophic consequences are likely to ensue from rising sea levels, to reduced water availability, to more heat waves and fires.

While our energy efficiency is improving, there is a very high correlation, almost near perfect correlation, between GDP growth, and energy usage.

Greece is an extreme case: a country where both the level of spending and the level of taxation were unsustainable!

We are already experiencing the symptoms of climate change, especially with a hotter and drier climate in southern Australia - the rush to construct desalination plants is an expensive testament to that.

My commitment to the Republican movement was pure and simply patriotism, a love of Australia... a desire or passion that all of our national symbols should be unequivocally and unambiguously Australian.

To the former child migrants, who came to Australia from a home far away, led to believe this land would be a new beginning, when only to find it was not a beginning, but an end, an end of innocence - we apologise and we are sorry. To the mothers who lost the maternal right to love and care for their child - we apologise, and we are sorry.

In economics, one of the most important concepts is 'opportunity cost' - the idea that once you spend your money on something, you can't spend it again on something else.