Opinion: Bali or bust

Matthew England 

We climate scientists have long had our noses in the books, swatting up on physics and dynamics, examining experimental results, putting on lab coats, filling test-tubes.

It all started long ago. Way back in 1896 Svante Arrhenius published a paper that speculated that changes in the atmospheric concentration of carbon dioxide could alter the surface temperature of the earth.

Since then, climate scientists have been a diverse bunch: analysing ice core records and tree rings, voyaging across the ocean in stormy seas, debugging computer models, and trekking through rainforests measuring carbon fluxes.

Yet we have had a common goal: namely, exploring the earth's climate system. And despite the diversity in the climate science community, we've been organised enough to produce acclaimed reports on the science of climate change. The best example is the series of reports produced by the Intergovernmental Panel on Climate Change (IPCC). Somebody noticed, and they jointly awarded the 2007 Nobel Peace Prize to the IPCC and Al Gore.

Yet despite these achievements, climate scientists have generally steered clear of telling the world how to set its emissions targets. The attitude has always been this: climate scientists should stick to the science, not set policy. Fair enough.

But who is best placed to advise the world what greenhouse gas targets are needed to avoid dangerous climate change? Who should be setting the goals to reduce our carbon emissions over the coming years?

The answer is definitely not the fossil fuel sector. That would be like asking a tobacco company CEO whether you should quit smoking. Or a fast food chain what constitutes a healthy meal. Read "conflict of interest" in flashing neon lights.

To be fair, we equally cannot rely on conservation societies and environmental lobby groups for advice here. They possibly have the right answers, but they are not the experts: their advice is only as good as their sources.

Climate scientists in contrast have analysed in detail what the climatic impacts are likely to be for a whole range of greenhouse gas emissions scenarios. Much of the IPCC reports are devoted to this exercise. And this has been an ongoing activity for the past 20 years. The science is not new; we are just living at a time when people have become aware of the findings because the predictions are urgent and dire.

A whole suite of future projections have been assembled in that time. At the high end is the "business as usual" case. One of my colleagues recently dubbed this "The George Bush" scenario. You can guess how this unfolds: we do nothing, and the planet is set on an unknown path toward unprecedented warming, severe storms, large-scale ecosystems extinctions and the displacement of tens of millions of environmental refugees.

At the low end is what I'd call "the European scenario". Governments agree on drastic emissions reductions, the business sector invests heavily in a carbon-reduced economy, new technologies are born, we stabilise greenhouse gases at around today's concentrations, and the planet sees only moderate climate change in the 21st century.

Two things are painfully sobering about the above two scenarios. The first is that even under the low-emissions scenario we are only minimising the risk of dangerous climate change. Hurricane Katrina is a good example of what can occur in a mildly warmed planet. We have already made a commitment to changing our climate into the 21st century from our 20th century emissions.

The second and vastly more sobering fact, though, is that we are currently tracking above the IPCC "worst-case" emissions scenarios. Yes, the "George Bush" scenario is right now looking half decent compared to where we seem headed.

This was unthinkable 20 years ago. Back then my PhD supervisor advised me not to consider that range of emissions scenarios in a climate change study. His words: "We'll never go there, that'd be ridiculous."

Yet we are there, and we are there now. And the scientific community is deeply troubled that their knowledge and expertise is not gaining greater traction with the policy-makers. This is why in December 2007, 212 of the world's leading climate scientists warned the United Nations Climate Change Conference in Bali of the need to act immediately to cut greenhouse gas emissions. The "Bali Climate Declaration by Scientists" set a window of only 10-15 years for global emissions to peak and decline, with a goal of at least a 50% reduction by 2050.

This declaration was signed by an elite group of climate scientists: to those in the field it reads as a "who's who" of lab directors, academy fellows, IPCC lead authors, and prize winners. And unlike the average scientific document, the declaration is short and sharp, with a very clear conclusion. And it came hot on the heels of a major statement by the world's business community seeking certainty in emissions reductions, and importantly, that these be set by scientists.

The Bali Climate Declaration has made the scientific view on emissions targets patently clear. It is now over to the policy makers to give the planet a decent future.

Professor Matthew England is an ARC Federation Fellow and co-Director of the UNSW Climate Change Research Centre.  He led the writing and release of the 2007 "Bali Climate Declaration by Scientists".  This declaration can be viewed at http://www.ccrc.unsw.edu.au/news/2007/Bali.html

Professor Matthew England is Director of the Climate and Environmental Dynamics Laboratory (CEDL), University of New South Wales.

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