The Earth’s atmosphere and oceans are vulnerable to small changes in greenhouse gas levels, aerosols, extent of the ice sheets and vegetation cover. The climate system can change rapidly over short periods of a few decades, crossing thresholds and points of no return. New studies reported by leading climate scientists indicate the Greenland and west Antarctica ice caps would, if atmospheric CO2-equivalent concentrations reached 450 ppm, very likely melt rapidly, raising sea-level on the scale of metres per century.

Recent developments in the state of the Earth’s climate include increasing extent of spring melt of Arctic Sea ice, mid-winter breakup of the Wilkins ice shelf in West Antarctica, and large methane leaks offshore of eastern Siberia, compel us to call for urgent measures to reduce greenhouse gas emissions. With the demise of Arctic Sea summer ice likely within the next decade, the global climate system is rapidly changing. CO2 emissions, currently rising at more than 2 per cent per year, should be decreasing at a similar rate if further adverse effects are to be avoided.

In a letter of the 27 March 2008, to Kevin Rudd, Australia’s Prime Minister, Professor James Hansen, NASA’s chief climate scientist, states:

Global climate is near critical tipping points that could lead to loss of all summer sea ice in the Arctic with detrimental effects on wildlife, initiation of ice sheet disintegration in West Antarctica and Greenland with progressive, unstoppable global sea level rise, shifting of climatic zones with extermination of many animal and plant species, reduction of freshwater supplies for hundreds of millions of people, and a more intense hydrologic cycle with stronger droughts and forest fires, but also heavier rains and floods, and stronger storms driven by latent heat, including tropical storms, tornados and thunderstorms.

Australia is one of the countries which stand to suffer most in this regard. Mid-latitude agricultural zones of Australia are vulnerable to climate change in terms of severe droughts, subtropical Australia is susceptible to increasingly frequent 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 winter half-year rainfall over southern parts of Australia, including the wheat belts of southwestern Western Australia, Victoria and the southern half of the Murray-Darling Basin. By contrast, precipitation is increasing in northwestern Australia.

Observed warming and acidification of the oceans is predicted to increase resulting in severe decline of marine life and food resources, in particular Australian’s national treasure – the Great Barrier Reef.

On the other hand, Australia is blessed with plentiful solar, tidal, wind and geothermal energy, which with energy storage and networking can supply base-load power. We should seize the opportunity to grow new sustainable industries and employment. Large-scale investment in these industries would strengthen our economy as world demand for low-carbon emissions energy grows.

A window of opportunity exists to attempt to halt a climate crisis by means of:

• Urgently cutting carbon emissions.
• Seizing the opportunity to fast-track utilisation of established and new clean energy technologies thus creating new business opportunities.
• An urgent tree-planting campaign in Australia and its neighbors.
• Attempts at CO2 capture through soil-carbon enrichment and preservation.

Recommended policies include:

• Australia to make every effort through its own and international actions to prevent CO2 -equivalent levels from rising above 450 ppm and global warming from rising above 2 degrees C relative to pre-industrial temperatures, as is the European target. Further reduction of CO2 levels to 300-350 ppm may be required to have a reasonable probability of restoring a safe climate.
• Carbon emissions need to be reduced locally and globally by 25-30 per cent by 2020 and 60-80 per cent or more by 2050 in an attempt to stabilise the climate.
• Major improvements in public transport and rapid development of more energy-efficient private transport.
• Major efforts at farm-friendly revegetation in Australia and neighboring countries, aimed at carbon capture and erosion control.
• Development, with suitable incentives, of large-scale clean energy utilities, including solarpowered thermal, geothermal, tidal and solar powered-desalination and wind-water extraction plants in outback regions, using an extended electricity grid (possibly including highly efficient high voltage DC cables) to supply electricity to major consumer markets.
• Emphasis on development of the above (item 5) for remote and indigenous communities, enhancing new employment opportunities, thus reducing social problems.
• Development of adaptation and protection strategies to minimise the coastal impacts of sea level rise.
• Active encouragement of water tank storage associated with residential, business and industrial properties and paved areas. (This avoids increasing evaporative losses from soils and dams.)
• Active diplomacy, tied to aid, for adaptation to and mitigation of climate change, to convince developing countries, as well as the United States, to commit to substantial reductions in greenhouse gas emissions, including constraints on emissions from Australian coal exports. We must lead by example – not asking others to do as we say, but to do as we do.

We must face the challenge and seize the opportunities in dealing with climate change. We face a choice between climatic disasters and directing resources to stabilise the Earth’s climate for future generations. We need to invest in low-carbon technology and we need to do it now. 

This is a statement prepared by Dr Barrie Pittock PSM (former leader, Climate Impact Group, CSIRO, IPCC Lead Author, and author of “Climate Change: Turning Up the Heat”), and Dr Andrew Glikson (Earth and paleoclimate research scientist, former Principal Research Scientist, AGSO; Visiting Fellow, Australian National University).

For a list of leading and senior scientists in the natural sciences (environment, climate, biology, Earth science) who have endorsed the Pittock and Glikson climate statement see the original blog on AusSMC.