How to crash a planet: Just follow Garnaut

September 13, 2008

On September 5, the government's climate change adviser, Professor Ross Garnaut, released his recommendations for medium-term cuts to Australian greenhouse gas emissions.

To the outrage of environmentalists, Garnaut's report, Targets and trajectories, calls for reductions by 2020 of just 5% if there is no comprehensive international agreement on emissions reductions, or of 10% if there is. At the Bali climate summit last December many developed countries, although not Australia, expressed support for goals of 25-40%.

PM Kevin Rudd and his ministers could yet reject Garnaut's targets, but this is unlikely. Business groups are already voicing satisfaction at the proposed "soft start" to the new emissions reduction regime.

Garnaut reportedly worked out his objectives on the basis of a per capita formula that takes into account the expected increase in Australia's population due to immigration. But this is unlikely to cut much ice with other developed countries. Under the same formula, the Weekend Australian noted on September 6, Canada would have to reduce its emissions by 33%, and Japan by 27%.

The Rudd government's carefully burnished reputation for boldness and principle in combating climate change now seems destined for the scrapheap.

Flawed fundamentals

Garnaut's new report, prepared on the basis of treasury department modelling, ranges widely over questions that include future economic growth, likely electricity costs, and carbon prices under the government's planned emissions trading scheme. One of the report's more striking arguments is that an emissions cut of 10% would be quite cheap, reducing gross domestic product in 2020 by only 1.1%.

One of the truisms of computer modelling, however, is that if you don't get the fundamentals right, any results you derive are worthless. If Garnaut's proposed cuts do not do their job of stopping climate change, there is no way the outcomes will be cheap for most Australians.

And the truth, unfortunately, is that Garnaut's fundamentals are very flawed indeed. Much of his work is turned into a statistical fairy tale by his insistence on ignoring the climate science of the last few years.

Addressing the National Press Club on September 5, the Weekend Australian recorded the next day, Garnaut "defended his proposed 'first stage' target of stabilising carbon in the atmosphere at 550 parts per million, saying it was his 'reluctant conclusion that a more ambitious international agreement is not possible at this time'".

Much could be said about Garnaut's decision to limit his target to what he guessed the energy profiteers and pro-polluter politicians of the world might accept. But here, let us address his science. Garnaut's target of 550 parts per million of carbon dioxide would roughly double the 280 ppm that existed in the mid-18th century, before the industrial era began. The degree of global warming that results from such a doubling is referred to by scientists as the Earth's "climate sensitivity".


The precise figure for climate sensitivity remains a focus of study and debate, but until recently the most common view put it at about 3° Celsius above pre-industrial levels. This figure, however, reflects mainly so-called "fast feedbacks". These relate to the impacts of increased emissions on factors such as atmospheric water vapour, clouds, and sea ice, whose effects work through the climate system quite rapidly.

The real world, however, is more complex. There are also "slow feedbacks" — the effects on temperatures of factors such as ice sheets, vegetation, carbon in soils, swamps and oceans. These slow feedbacks may come into play only over many decades. Because slow feedbacks are hard to quantify, scientists have only in the last few years been incorporating them in a major way into computer models of the global climate.

This new work raises some scary questions. What if slow feedbacks mean that the Earth's climate is far more sensitive to greenhouse gas emissions than was earlier thought? What if even today's warming — of 0.7°C above pre-industrial levels — results in the area of Arctic sea ice shrinking rapidly, allowing the sun to warm Arctic waters at a much faster rate? And what if the warmer Arctic temperatures cause frozen ground — permafrost — to thaw, releasing huge quantities of stored methane, a potent greenhouse gas? Researchers are already observing such effects.

What if global temperatures only a little warmer than at present result in the destruction of the Amazon rainforest, and the release of vast amounts of carbon dioxide once locked up in trees and soils? This is an entirely serious prospect.

Warming of 3°C (or even 2°C, once thought "safe") would almost certainly take the Earth past the "tipping point" at which a series of such slow feedbacks would be triggered. A doubling of atmospheric carbon dioxide, therefore, would not necessarily result in global temperatures stabilising at 3°C above pre-industrial levels, but at some much higher figure.

Paleoclimatic evidence

We now have a meaningful prediction of where this real-world stabilisation might occur. In April, a team headed by James Hansen, head of NASA's Goddard Institute for Space Studies and arguably the world's pre-eminent climate scientist, released a paper that took a series of slow feedbacks into account. This work represented a big advance in that it used extensive data from the paleoclimatic record — that is, hard evidence from studies of what climates were like tens of millions of years ago, when greenhouse gas levels were much higher.

Hansen and his team concluded that in the present-day a doubling of atmospheric carbon dioxide — to Garnaut's 550 ppm — would most likely result in a rise of about 6°C. The new average global temperature would be higher than it has been for tens of millions of years, since a time when the Earth had no icecaps and its plants and animals were profoundly different.

Such a temperature rise would mean countless species would become extinct. Populations of those that remained would be radically unstable, marked by wild booms and crashes.

Could billions of human beings survive in such circumstances, especially with broad areas of fertile lowland swamped by rising seas? Quite probably, the result for humanity would be population crash, perhaps to only a few million people, and the end of advanced civilisation.

To prevent such a catastrophe, Hansen and his collaborators urge prompt, determined action to cut atmospheric carbon dioxide from its present level of 388 ppm to "at most" 350 ppm. Should it prove necessary to restore Arctic sea ice to its area in the middle of last century — as now seems imperative — the scientists argue that the target will have to be 300-325 ppm.

These conclusions, some of the best-founded that modern science has to offer, show Garnaut's projections to be close to suicidal. Why, then, are government offices not besieged by furious citizens demanding the right for their grandchildren to stay alive?

The key reason is that the more unnerving findings of climate science in the past few years have been systematically ignored and concealed by government bodies and the corporate media.


With the release last year of the fourth assessment report of the UN Intergovernmental Panel on Climate Change (IPCC), governments and the media were forced — with some notable exceptions — to accept that climate change was real, and that human agency was largely responsible.

The IPCC's report, however, was intentionally conservative — many would say too conservative — in the conclusions it drew from its data. Also, it was by no means up-to-date; in a rapidly advancing field, the cut-off point for the science it incorporated was 2005. This meant that in the IPCC's modelling, work to quantify slow climate feedbacks found almost no reflection.

Nevertheless, the IPCC's report remains the informational baseline for the treasury department officials who are Garnaut's key collaborators. Findings since 2005, no matter how momentous and authoritative, are treated as speculative.

Among Canberra public servants, treasury officials are notorious for their ideological "dryness". In this, they resemble the editors of the corporate media. Not surprisingly, the advances that have taken climate science well beyond the IPCC's last report almost never feature in the pages of major newspapers.

Hansen, despite his towering scientific reputation and vigorous public advocacy, has been virtually ignored. One of the few times the Australian has mentioned him was on July 5, when it printed a vicious attack on his professional integrity.

Blind-sided by the lethal deceptions of the political establishment, most people can be pardoned for not having grasped the horrifying message of the latest climate science. The leaders of environmental groups are not so readily excused. Bullied by government and the media, they have failed to spell out the full danger the world faces, reasoning perhaps that such frankness would cost them what little chance they have of influencing policy.

Quoted in the Adelaide Advertiser on September 6, Australian Conservation Foundation executive director Don Henry complained of Garnaut's "weak targets", which would "condemn the Great Barrier Reef and the Murray Darling to destruction".

The danger, however, is infinitely greater than that.

And what of Garnaut himself? Opting for "soft" targets, he evidently hopes to encourage governments around the world to get on board the process of negotiating a global emissions agreement. "My aim is to nurture the slender chance that humanity can get its act together", he told the National Press Club on September 5.

Unrealistic targets, however, provide false assurances, and the confusion they create can put immense obstacles in the way of effective action. Meanwhile, time for the world's ecosystems — and for humanity — is running out.

There is no substitute for fearlessly putting the best available information and analyses before the people. If the action we then demand is not to the liking of the political and business elites, we can decide for ourselves whether these elites ought to survive.

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