11.3.2 Population, energy and agriculture
The Australian population is projected to grow from 20 million in 2003 to 26.4 million in 2051, then stabilise (ABS, 2003a). This is under medium assumptions, including a fall in the number of children per woman from 1.75 at present to 1.6 from 2011 onward, net immigration of 100,000/yr, and a 10% increase in life expectancy by 2051 (ABS, 2003a). A greater concentration of the population is likely in Sydney, Melbourne, Perth, Brisbane and south-east Queensland. The proportion of people aged 65 and over is likely to increase from 13% in 2003 to 27% in 2051 (ABS, 2003a). Population growth is likely to intensify the urban heat island effect, exacerbating greenhouse-induced warming (Torok et al., 2001). Up to at least 2020, Australian energy consumption is projected to grow 2.1%/yr on average (ABARE, 2004). New energy sources will be needed to meet peak energy demands in Victoria, NSW, Queensland and South Australia between 2007 and 2010 (NEMMCO, 2006). Agriculture is likely to contribute about 3% of national gross domestic product (GDP).
In New Zealand, under medium assumptions, the population is likely to grow from 4.1 million in 2004 to 5.05 million in 2051 (Statistics New Zealand, 2005b). These assumptions include a net immigration of 10,000/yr, a drop in fertility rate from 2.01 in 2004 to 1.85 from 2016 onward and a 10% increase in life expectancy by 2051. The proportion aged 65 and over is likely to grow from 12% in 2004 to 25% in 2051. Total energy demand is likely to grow at an average rate of 2.4%/yr from 2005 to 2025 (Electricity Commission, 2005). Agriculture is likely to continue contributing about 5% of GDP (MFAT, 2006).