Facts and Figures

• Predictions in the Third IPCC assessment report on climate change include: continuing global warming – a rise of the Earth’s temperature from 1.4°C to 5.8°C by 2100; changes in weather and climate – e.g. more severe droughts and floods; and greater rises in sea level – from 9 to 88cm by 2100.

• Australia’s human-induced emissions of greenhouse gases are among the highest per capita in the world at around 27 tonnes per person per year, comparable with those from North America and New Zealand but higher than those from countries across Europe. Both the thin spread of the Australian population across the continent and the inputs of fossil fuels needed to produce exports that underpin our standard of living contribute to Australia’s high per-capita emissions.

• The Earth’s average temperature has warmed by about 0.6 of a degree over the last 100 years, with most of this warming occurring in the last 20 years. In Australia, the same pattern has occurred, with average temperatures having jumped by about 0.7 of a degree, mostly in the last 50 years.

• The biggest source of carbon dioxide emissions globally is the generation of energy. The most common way to generate energy is to burn coal for fuel – it is also the most polluting. 77% of Australia’s electricity comes from burning coal, making us one of the top coal-burning countries in the world.

• The impacts of the rapid warming of our planet are evidenced in Australia by the hotter climate conditions we are now experiencing, the increase in the severity of drought and bushfires, the decrease in water availability, the loss of snow cover in some of our colder climes, and the bleaching of the Great Barrier Reef.

• The IPCC Draft Fourth Assessment Report says the tem-perature increase could be contained to 2¾C by 2100 if greenhouse gas emissions are held at current levels. In 2001, the scientists predicted temperature rises of between 1.4¾C and 5.8¾C on current levels by 2100, but better science has led them to adjust this to a narrower band of between 2¾C and 4.5¾C.

• Modelling previous to the Fourth Assessment Report suggested that sea levels could rise by almost 1 metre over the same period. The latest report projects a rise in sea levels by century’s end of between 14cm and 43cm, with further rises expected in following centuries caused by melting polar ice.

• According to current climate change models, stabilising global greenhouse gas levels to 400 parts per million offers a good chance of avoiding 2¾C global temperature increases. This would require global emissions to be 50% below 1990 levels by 2050.

• The CSIRO recently concluded that the goal of 60% reductions might be considered the minimum needed to avoid dangerous climate change. Any further reductions in global temperatures would require cuts in emissions of about 80-90% in industrialised countries by 2050, which would require a faster transition to near-zero emissions technologies.

• The Earth has warmed, on average, by about 0.7°C since 1910 with 9 of the 10 warmest years on record occurring in the past decade. There has been an increase in heatwaves, fewer frosts, and a warming of the lower atmosphere and upper ocean.

• Australian temperatures have increased by almost 0.9°C over the last hundred years, which is slightly more than the global average.

• Much of the warming since 1950 is due to human activities that have increased greenhouse gases. This is known as the enhanced greenhouse effect. Atmospheric carbon dioxide levels have increased by 35% from pre-industrial times. Ice core records indicate this current level is higher than at any other time in the past 420,000 years.

• The results of climate change include: retreat of glaciers and sea ice; a decline of 10-15% of the Arctic sea ice extent and a 40% decrease in average thickness; snow depth at the start of October has declined 40% in the last 40 years in the Australian Alps; an average sea level rise of 20mm per decade over the last 50 years; changes in mating and migration times of birds; poleward and altitudinal shifts of plants and animals; an increase in coral bleaching due to increased water temperature.

• Projections for Australia are for a hotter climate with more frequent extreme events. It is estimated that there will be: warming of 0.4-2°C by 2030 and 1-6°C by 2070 compared to 1990 (warming will not be the same everywhere but almost everywhere the climate will be different); more hot days over 35°C (up to 3 times as many by 2070) and a reduction in the number of frost days; an increase in the frequency and duration of extreme events such as heavy rains, cyclones, floods, and droughts; a rise in sea level of 9 to 88cm by 2100 compared to 1990.

• Climate change has been identified as one of numerous pressures on the world’s wildlife. It has led to some 25% of the world’s mammals and 12% of birds being at significant risk of extinction.

• Minimal climate warming scenarios for 2050 could lead to extinction of approximately 18% of species. Mid-range, and maximum, warming could lead to extinction of 24% and 35% of species, respectively, by 2050.

• Climate change will cost the global economy at least 5% of GDP each year – without remedial action being taken. The damage bill could rise to more than 20% of GDP. (p.23)
n The concentration of greenhouse gases would cause global temperatures to rise by an average 2 degrees. In the long term, there is a more than 50% chance the rise will exceed 5 degrees.

• It is no longer possible to arrest climate change develop-ments over the next 20-30 years. The strategy is to reduce its impact. The aim should be to stabilise greenhouse gas levels in the atmosphere – this would require emissions to be at least 25% below current levels by 2050. The cost of such action is estimated at 1% of GDP. Ultimately, stabilisation requires annual emissions to be brought down to more than 80% below current levels.

• Global response to climate change involves three policy strands: effective carbon pricing, development of low-carbon technologies and removal of barriers to energy efficiency.