Professor Ross Garnaut has said that ‘Climate change is a diabolical policy problem’, but this may be an understatement. In 2008, after nearly two years of work, he delivered the final report of the first Garnaut Climate Change Review, which had been commissioned by the state and federal governments. This served as ‘one of the inputs’ to the development of the federal government’s failed legislation for the Carbon Pollution Reduction Scheme in 2009. The political debate over that legislation played a major role in Malcolm Turnbull’s losing the leadership of the Opposition to Tony Abbott, and Kevin Rudd’s subsequently losing the prime ministership to Julia Gillard.

In November 2010, Garnaut was commissioned again by the Australian government to provide an update to his Review: in particular ‘to examine whether significant changes had occurred that would affect the key findings and recommendations reached in 2008’. He accepted this challenge and led another massive effort in the battlefront on climate change, completing the review in only seven months and with a reduced team. The Garnaut Review 2011 is a synthesis of material from eight update papers on specific topics and two supplementary notes, all focusing on Australia’s responses to global climate change.

It is not clear why Garnaut accepted this most difficult challenge, re-entering the fray of providing advice to policy-makers, but we should all be grateful that he has. This book is surprisingly readable for a text on economics and policy responses. It is liberally sprinkled with short anecdotes from his encounters with a wide range of political and economic leaders around the world over the last three years. These vignettes provide a human touch and illustrate the different perspectives and responses to climate change in different countries.

Much has happened in the past two and a half years: the global financial crisis of 2008; a federal election; many new scientific studies of observed climate change and projected future changes; and action in response to climate change in many countries.

Garnaut considers the new scientific studies on climate change and concludes that the evidence has strengthened since his first Review. Rather than his earlier assessment ‘on the balance of probabilities’, he now concludes ‘beyond reasonable doubt’ that global climate change is happening, that most of this global climate change is due to human-caused emissions of greenhouse gases, and that continued emissions of greenhouse gases will cause even greater climate change this century, with substantial impacts in Australia on human and natural systems. It is no surprise that his findings tally with those of the Australian Academy of Science and the scientific academies of many other countries, as well as with the vast majority of active research climate scientists around the world. Of course, there are a very small number of climate scientists and a much larger number of opinion leaders and journalists, such as Alan Jones and Andrew Bolt, who do not accept these conclusions. They are welcome to their opinions, but not to their own facts.

Next, Garnaut considers the continued emissions of carbon dioxide and other greenhouse gases from burning fossil fuels, agriculture, and industrial activity in Australia, as well as scenarios for future emission reductions aimed at limiting increases in global average temperature to only two degrees Celsius above pre-industrial ones, the target that was agreed at the Copenhagen and Cancun climate conferences in 2009 and 2010. This global temperature target is consistent with stabilisation of greenhouse gas concentrations in the atmosphere at a level of about 450 parts per million (ppm) carbon dioxide equivalent. It is also consistent with cumulative emissions of carbon dioxide from burning fossil fuels of about one trillion tonnes from 2000 to 2050. Garnaut argues that rapid and substantial global reductions of greenhouse gas emissions are required, but that overshooting these targets may be necessary, to allow a slower initial reduction in emissions.

However, Garnaut understates the magnitude of the likely overshoot of these targets. The concentration of long-lived greenhouse gases in the atmosphere in 2010 was already 470 ppm carbon dioxide equivalent, according to the NOAA Annual Greenhouse Gas Index – substantially above the 450 ppm target. Global emissions of carbon dioxide from 2000 to 2010 had already used up about a third of the cumulative emissions budget to 2050 in only a fifth of the period. Rapid, substantial, sustained reductions of greenhouse gas emissions from human activity are needed to minimise dangerous climate change.

So what is a fair share for Australia of these global emission reductions, and what are other countries doing to reduce their emissions? The book compares the pledges for emission reductions made in Copenhagen by both some developed and some developing countries. While substantial action on reducing greenhouse gas emissions is already happening, these pledges are too small to achieve the 450 ppm stabilisation target.

To develop Australia’s fair share, emissions of greenhouse gases per person are considered. As Australians, we are among the highest emitters at about twenty-seven tonnes of carbon dioxide equivalent per person per year, while Indian emissions are about two tonnes per person per year. Garnaut recommends that global emissions per person should converge and contract to the same amount by 2050, with emissions in developed countries falling rapidly and those in developing countries rising slowly. He argues that the range of conditional targets accepted by the Australian government for emission reductions from five per cent to twenty-five per cent below 2000 levels still seem appropriate. However, he also points out that only the twenty-five per cent emission reductions for Australia are consistent with the 450 ppm target.

Unfortunately, there is an inconsistency in this approach. If a cumulative emissions budget is appropriate for determining global emissions reductions, it should also be relevant for assessing a country’s fair share. With a world population of just under seven billion people, the global emissions budget translates into a personal emissions budget of a little more than 140 tonnes of carbon dioxide from burning fossil fuels from 2000 to 2050. With Australian emissions of carbon dioxide from burning fossil fuels at about nineteen tonnes per person, this means that we have each used up our personal budget of carbon dioxide emissions from 2000 already. While it is obviously not practical to switch off all emissions of carbon dioxide from burning fossil fuels in Australia overnight, that is what the cumulative emissions budget approach shows should be our fair share; zero emissions for the next forty years, our emissions having been so high in the past. Anything more would not be fair globally. But, of course, we don’t live in a fair or equitable world.

The remaining two parts of the book consider the different approaches for Australia to achieve significant emission reductions and to address climate change. These include setting a price on greenhouse gas emissions, a so-called carbon price, as well as providing compensation for the most vulnerable people in the community and for trade-exposed industries. He points out that the mining boom in Australia and the associated appreciation in the value of the dollar have had a much greater impact on local jobs and manufacturing industries than has the proposed carbon price. These approaches also include regulations to improve energy efficiency in buildings (residential and industrial) and measures to transform the electricity sector through the introduction of low emission renewable energy technologies. Australia has greater potential for generating electricity from solar, wind, wave, or tidal energy sources than does any other country in the world, which provides great opportunities for the future.

Efficient and effective adaptation to climate change will be vital for Australia to minimise the adverse impacts and to seize the opportunities arising from climate change. Garnaut argues that efficient markets, for finance, for food, and for water, are essential for effective adaptation. I hope that his trust in markets is justified, as he also considers climate change to be the greatest market failure experienced by modern society.

Garnaut describes the necessary transformations of the land sector, including changes in agricultural practices, reducing deforestation, increasing plantation forests, and harnessing waste for bioenergy production. These can reduce greenhouse gas emissions, as well as help to restore Australian ecosystems.

While the focus of this book is on Australian impacts due to climate change, it is important to remember that climate change is a global issue with major repercussions for many vulnerable communities in developing countries, ones that are least responsible for this problem. An ethical response to climate change requires consideration of these impacts on all vulnerable communities, not only those in Australia. While economic arguments provide one approach to compare different responses to climate change, they should not override ethical considerations.

While I have some concerns about a few aspects, The Garnaut Review 2011 is an excellent book. In comprehensive style it covers the complex issue of climate change and Australian responses in a very accessible manner. It provides the necessary ammunition to combat the barrage of misinformation that seems to be part of the ‘debate’ on policy responses to climate change in Australia. Ross Garnaut must be congratulated for his efforts once again to provide a sound basis for policy in Australia – and for entering the breach once more.