Guest Post by Dr Andrew Glikson (former Principal Research Scientist, AGSO; Visiting Research Fellow, Australian National University) and Dr Barrie Pittock (Honorary Fellow, CSIRO Marine and Atmospheric Research; former leader, Climate Impact Group, CSIRO).
THE GLOBAL VIEW
In a recent published statement (18 May, 2007) Professor James Hansen, NASA’s Chief Climate Scientist, states: ‘The Earth today stands in imminent peril and nothing short of a planetary rescue will save it from the environmental cataclysm of dangerous climate change’.1
Professor Hansen’s statement is consistent with the 4th IPCC Report 2, which states: ‘Global atmospheric concentrations of carbon dioxide, methane and nitrous oxide have increased markedly as a result of human activities since 1750 and now far exceed pre-industrial values determined from ice cores spanning many thousands of years’. The IPCC Report projects temperature rises in the range of 1.1 to 6.4ºC for the 21st century, depending on human carbon emissions2.
A major conclusion from the recent history of Earth indicates the atmosphere, climate systems, the oceans and ice sheets are extremely vulnerable to even minor changes in natural forcings, including solar and greenhouse forcing, atmospheric particulates and ice reflectance/albedo changes.
Following completion of the draft IPCC-2007 Report early in 2006, concern has been expressed by leading climate scientists regarding the pace of climate change. The balance of evidence may be swinging toward a more extreme climate change outcome, including4:
1. Global warming In the probable range of 2º–6°C by 2100, with more than a 50% probability of 3ºC or higher, a dangerous level in terms in droughts, storms, sea level rises and many other impacts.
2. Reduction in atmospheric particles and increase in permafrost melting reduce reflectivity (albedo), increase temperatures and positive feedback (amplification) by carbon dioxide and methane.
3. Climate change accelerated by emission from drying vegetation and increased wild fires.
4. Arctic sea ice rapid retreat speeds up global warming as reduced sunlight reflection increases surface heating.
5. Changes in air and sea circulations in mid and high latitudes results in pole-ward migration of climate zones and mid-latitude westerlies, transporting more heat pole-wards and changing rainfall patterns, and increases in storminess.
6. Rapid disintegration of ice shelves and acceleration of outflow glaciers in Greenland and Antarctica are adding to ice sheet melting, reduced reflection of sunlight, global warming and sea-level rise.
7. Tropical cyclones becoming more intense.
Sea level rise projections by the 4th IPCC Report in the range of 0.18 to 0.59 metres by 2100 (Working Group I Table SPM-2)3 take too little account of rapid changes in ice flow. However, such dynamical changes are now reported from both Greenland and west Antarctica5, with revised sea level rise estimates of 50 to 140 cm by 21006 and 3 to 5 metres by 2300, based on linear temperature-sea level relationships6. Nonlinear projections based on doubling of Greenland melt area and sea level rise over the last two decades predict sea level rises on the scale of about 5 metres7. Rahmstorf et al. 8,9 indicate CO2, temperature and sea level rises are currently tracking at the top of the 4th IPCC-2001 range of projections relative to 1990.
Sea level rise would flood and seriously damage much of the current world coastlines, including small island states, many large cities, most beaches and many coastal ecosystems.6,7
IMPLICATIONS FOR AUSTRALIA 3,11
Mid-latitude agricultural zones of Australia are vulnerable to climate change in terms of severe droughts, subtropical Australia is susceptible to the El-Niño effects and cyclones, and the concentration of Australia’s population in coastal zones and cities places the nation at risk from sea level rises. Already the pole-ward migration of climate zones is affecting Australia through the southward retreat of the moist westerlies and consequent decreased rainfall over southern parts of Australia, including the wheat belts of southwestern Western Australia, Victoria and the Murray Darling Basin. By contrast, precipitation is increasing in northern and northwestern Australia.
Specific social and economic risks for Australia include3, 11-16
1. Drying of southern and eastern regions associated with bush fires, erosion, ecosystem losses and major economic impacts.
2. Sea level rise and storm surges with major impacts on coastal development, infrastructure, saline intrusion, loss of coastal wetlands.
3. Warming: crops and forests stressed, species threatened, fire, coral reef bleaching.
4. Severe floods and storms, large capital costs and down time.
5. Acidification of oceans, with consequent effects on marine life, reefs and fisheries.
6. International refugee and economic crisis arising from sea level rise and flooding of large population centers, in particular throughout southeast Asia (including Pacific and Indian Ocean islands, Bangladesh , and coastal cities and heavily populated deltas and low river valleys in China, Viet Nam, India and Pakistan).
7. Severe disruption of sea trade due to port/harbor flooding.
Recommended policies include:
1. It is essential Australia determines to make every effort to help prevent CO2 levels from rising above 500 ppm and global warming from rising above 2 degrees C relative to preindustrial temperatures, as is the European target.
2. Carbon emissions need to be reduced by 60-80% by 2050 to stabilize climate, commencing with reductions of 20-30% by 2020-2030, or 4-5% reductions per annum relative to business as usual.
3. Major improvements in public transport and rapid development of more energy-efficient private transport.
4. Major efforts at revegetating dried areas and planting new forests, aimed at carbon sequestration and erosion control.
5. International negotiations and agreements placing constraints on emissions from Australian coal exports.
6. Asia-Pacific Partnership (AP6) to be seriously strengthened to achieve less than the minimum 1.7°C warming by 2100 (relative to 1990) that was projected to result from AP6 by ABARE.17
7. Major incentives for development of clean energy technologies, including solar, wind, geothermal (hot rocks), hydrogen, tidal and wave.
8. Development of solar-powered coastal and ground water desalination systems.
9. Major incentives for development of large-scale clean energy utilities, including solarthermal, solar-desalination and wind-water extraction plants in outback regions using highly efficient high voltage DC cables to supply electricity to major cities10.
10. Emphasis on development of the above (item 9) for indigenous communities, enhancing new employment opportunities, thus reducing social problems.
11. Development of coastal protection and adaptation strategies.
12. Universal application/construction of water tank storage associated with residential, business and industrial properties.
The state of the Earth atmosphere which has allowed agriculture and civilization to flourish is changing fast. This is now acknowledged by the highest scientific and political authorities. Such are the scale and the urgency of the issue, it places future generations and much of the progress which has been achieved in relation to human civilization, human welfare and human rights in grave jeopardy. We are concerned that, due to inertia in the political system, the urgent mitigation required to arrest runaway climate change may not be forthcoming. Australia is in a pivotal position vis-à-vis climate change due to its coal wealth and good relations with relevant countries. The gravity of the situation calls for renewed efforts on an apolitical basis in an attempt to avert the worst consequences of runaway climate change.
2. IPCC 4th Report, Climate Change 2007: SPM of Working Group I, The Physical Science Basis. 5th February, 2007. http://www.ipcc.ch
3. IPCC-2007 4th Assessment WGII chapter on Australia and NZ. http://www.ipcc.ch
4. Pittock, A.B., 2007, EOS 87, No. 34, 22 August, 2006, and Washington Summit on Climate Stabilization, 18-21September, 2006, http://washington_summit.climate.org/abstracts/pittock_tenreasons.html
5. Bamber et al., 2007. Rapid response of modern day ice sheets to external forcing. Earth. Planet. Sci. Lett., 257, 1-13, and Shepherd, A. and D. Wingham, 2007, Recent sea-level contributions of the Antarctic and Greenland ice sheets. Science, 315, 1529-1532.
6. Rahmstorf, 2007. A Semi-Empirical Approach to Projecting Future Sea-Level Rise Science, 315, 368-370.
7. Hansen, J.E., 2007: Scientific reticence and sea level rise. Environ. Res. Lett., 2, 024002, doi:10.1088/1748-9326/2/2/024002.
8. Rahmstorf, S. A. Cazenave, J.A. Church, J.E., Hansen, R.F. Keeling, D.E., Parker and R.C.J. Somerville., 2007. Recent Climate Observations Compared to Projections. Science, 316, 709.
9. Rahmstorf, S, 2007. Climate Change Fact Sheet, Potsdam Institute for Climate Impact Research (http://www.pikpotsdam.de/~stefan)
10. see http://www.TREC-EUMENA.net.
11. Pittock, A..B., 2007. The enhanced greenhouse effect: threats to Australia’s water resources. Part 1: Scenarios for the future. Jour. Aust. Water Assoc. 48-54
12. Pittock, A.B., 2007. The enhanced greenhouse effect: threats to Australia’s water resources. Part 2: Potential impacts and solutions. Jour. Aust. Water Assoc., 36-38.
13. Pittock, A.B., 2007. Keeping up to date on climate change. Clean Air (in press).
14. Climate Change and Infrastructure: Planning ahead. http://www.greenhouse.vic.gov.au.
15. Dupont, A. and Pearman, G. Heating up the planet, 2006. Climate change and security, Lowy Institute Paper 12. http://www.lowyinstitute.org.
16. Pittock, A.B., 2007. Climate Change: Turning Up The Heat. CSIRO Publishing, 316 pp.
17. ABARE Research Report 06.6, Australian Bureau of Agricultural and Resource Economics, available at http://www.abareconomics.com