Australian scientist speaks

Dr Graeme Pearman is Chair for Sustainability Science at Monash University. He is a member of Greenfleet's Advisory Council. From 1992 until 2004, Dr Pearman was Chief Scientist at CSIRO Atmospheric Research ....


"Climate change is being observed; it is happening. It will continue through this century as a result of continued emissions of greenhouse gases by each and every one of us.

"Australia is vulnerable because climate scientists anticipate a reduction of rainfall for much or Australia, with an increased frequency of extreme rainfall and temperature events, higher sea levels and thus impacts on both the natural and built environment.

"To prevent excessive warming, global reductions of emissions from current levels of more than 60% will be required over the first half of this century. This is an extraordinary challenge given current investment in energy technologies, the growing demands for energy of the developing world and the dependence of our living standards on energy usage. Reductions of as much as 80% may be necessary for developed countries.

"Greenfleet's greenhouse calculator helps identify for each individual or household [or organisation], just how much they are contributing to the problem, where the major emissions come from in their daily lives and what options they have available to play a personal part in the challenge of emissions reductions.

"The planting of trees contributes through storing carbon that would have otherwise resided in the atmosphere, in the wood and parts of trees, at the same time assisting in the maintenance of biodiversity and habitat for our native wildlife."

About greenhouse gas emissions 

  • In 2004, Australia's Chief Scientist Robin Batterham stated that the nation must halve its greenhouse gas emissions by 2050.

  • The sooner we act, and the more we can cut our emissions, the better the chance of limiting the impacts of climate change. 

Since World War 2, global fossil fuel use (oil, gas and coal) has more than tripled - along with the resulting greenhouse gas emissions. This has led to a 25% increase in the concentration of carbon dioxide, the main greenhouse gas, in the earth's atmosphere since the 1950s. This concentration is far higher than at any time over the past 400,000 years.

Ongoing research is not only confirming concerns about the extent of temperature rise and other impacts of this change, but is also highlighting the emerging risks of more abrupt and large scale impacts. For example, the warm currents flowing near some countries could stop. And because carbon dioxide remains in the earth's atmosphere for decades after it has been released, warming will continue after we cut emissions.

The sooner we act, and the more we can cut our emissions, the better the chance of limiting the impacts of climate change. The Hadley Centre website shows recent research that highlights these issues.

The Greenhouse Effect

  • The Earth is surrounded by a blanket of gases made up of water vapour, carbon dioxide, methane, nitrous oxides and others.
  • Radiant heat from the sun hits the Earth, and most of this is reflected, with some of this being trapped by the blanket of gases.
  • The blanket of gases retains the heat in the same way as a greenhouse lets light in, then traps heat - hence it is called 'The Greenhouse Effect'.

The Enhanced Greenhouse Effect

  • When we burn fossil fuels we release carbon in the form of CO2 (carbon dioxide).
  • This adds to the greenhouse gases in the atmosphere, and causes a gradual increase in temperature.
  • Thus the Greenhouse Effect becomes 'Enhanced', causing global warming.
  • The CO2 concentration in our atmosphere is now 30% higher than it was 200 years ago.

The Carbon Cycle

  • All life on Earth is based on carbon.
  • Plants grow through photosynthesis - using sunlight to break down CO2 to pure oxygen and carbon (in the form of wood).
  • As plants rot down, they eventually form fossil fuels such as coal, oil (which makes petroleum products like petrol, diesel and LPG) and natural gas over millions of years.
  • When these fossil fuels are burnt (using oxygen), the initial process of photosynthesis is reversed, and CO2 is formed.
  • When we burn fossil fuels we are thus reversing, over a very short timeframe, a process that took millions of years, so that extra CO2 builds up in the atmosphere. The only way that we can neutralise the effects of this is to plant more vegetation to 'lock up the carbon', and reduce our burning of fossil fuels.

Sources, Sinks & Carbon Credits

One of the realities of the development of Carbon Credits is that it is being driven by monetary rather than environmental consideration. We hear that Wall Street expects that it will be the largest traded commodity in history!!

The European Union is not keen on the establishment of major sinks created by planting trees, one of the many sticking points in the ongoing Kyoto saga. They argue that sinks should not replace reducing CO2 emissions drastically. Whilst agreeing with this last sentiment, we would argue that sinks should be an integral part of any strategy to reduce the impact of greenhouse gas emissions, as technologies that can offer “Factor 4” or “Factor 10” jumps in resource efficiency are mostly at the early emergent stages. We wonder whether the fact that Europe does not have land available for large-scale revegetation could have something to do with the EU position? Some climate modeling suggests that we will need to reduce our per capita emissions by in excess of 80% to stabilise the earth’s climate, so the sooner we get serious about addressing the sources/sinks imbalance the better!

Many large corporations have realised that monoculture forests planted with genetically modified trees can soak up large amounts of carbon, and investors can sell the timber and build a rotating harvest – good for business, good for woodchips and good for carbon storage. The trouble is, these trees are useless in terms of habitat, and this concept of replacement harvests puts huge pressure to rip out old growth forest and remnant vegetation and replace it with the bio-diversity wasteland that plantations inevitably are.

There was a lot of debate at the recent CoP 6 meeting at the Hague about ‘aforested’ and ‘deforested’ land, and what should and should not be allowed to count as a carbon sink, and ultimately be traded as carbon credits. The argument goes that you should not be permitted to clear land of vegetation, then plant it with a harvest timber, and claim the carbon as a new sink. However it shakes out, legislation is being put in place now to recognise the ownership of land separately from the timber growing on it and from the carbon rights. Next maybe we will have salinity and bio-diversity rights and credits.

However, there appears to be far more focus, especially in Australia, on establishing sinks through vegetation than on fast-tracking technologies to reduce emissions at their source.

Transport may be the biggest problem!

Transport is now the fastest growing source of CO2 emissions worldwide. There are currently 800 million cars on the roads, and the global ‘fleet’ is expected to reach 1.6 billion by 2030.

Petrol consumption in the USA has risen by over 11% in the last 10 years – not a very promising trend in a market already pretty well saturated with vehicles.

See also:  What You Can Do and Sustainable Transport

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