The heroes and villains in the Great Climate Debate

More than any other documentary in the last decade, An Inconvenient Truth featuring Al Gore’s slide show purporting to put forward the unadulterated facts on climate change, has galvanised mainstream political interest. Actors, British moguls and undergraduates have all jumped on the bandwagon, with the most recent development being a court challenge to a Hunter Valley coal mine development by a Newcastle student.

The documentary highlights the problems that emerge when a scientific issue is hijacked by political interests. Increasingly high profile public figures are strongly weighing in and proposing purely political solutions with limited reference to the changing state of science. Public discussion of the science is critical if we are to formulate consensus and a national response to the issue. However it is important that the evidence is not presented in a distorted way.

In An Inconvenient Truth Gore consistently mixes up scientific evidence with a political speechmaker’s tactics. For example, he tells us of his son’s near death experience following a car accident in order to make a point about our lack of appreciation of the precious things in life until they are almost gone. Government attitudes to global warming are also likened to the League of Nations’ appeasement of Hitler prior to the outbreak of World War II.

This manner of argument is completely inappropriate in the presentation of a scientific issue. Using the same tactic, one might highlight the fact that well-spoken public figures with a compelling alarmist story to tell are also known for causing mindless havoc. The panic generated by Orson Welles’ infamous radio broadcast of War of the Worlds is a case in point. However analogy has no bearing on the science of climate change.

As an institute whose members are involved in minerals related activities, the Australasian Institute of Mining and Metallurgy (AusIMM) sees the issues raised by the climate change debate as necessitating an informed public debate based on actual evidence rather than rhetoric. In particular, there are three key issues which could benefit from scientific and engineering expertise.

The first is the extent to which anthropogenically induced emissions of greenhouse gases can be linked to an increase in average global surface temperature. The second is the impact and reversibility of climate change. The third, and arguably most important issue, is how we can move forward with practical measures to reduce greenhouse gas emissions, both nationally and internationally.

The first issue, namely whether there is a causal link between the increase in greenhouse gases in the atmosphere and average surface temperature, is easily the most controversial. Global coverage of temperature has only been available for the past hundred or so years; reconstructions from before that time are based on data sets derived from boreholes, glacier lengths, tree rings and so on. Different scientists from across a range of disciplines have drawn different conclusions on what the data indicates.

Taken from a geological point of view, it can be legitimately argued that the current increase in surface temperature is part of the Earth’s natural global warming and cooling process. That is, rather than being caused by an increase in greenhouse gas emissions, the warming phenomenon is the product of the same natural processes that led to a Medieval Warm Period from AD 900-1300 and a Little Ice Age which started in AD 1280.

It is important at this point to highlight that the opinions among our geologist members on greenhouse gases and climate change is widely divergent: there are some who are deeply committed to the anthropogenically induced theory of climate change, while others hold sceptical views. However all are keen to see the debate take place in an informed environment.

The second key issue, namely, the impact and reversibility of climate change, falls outside our members’ area of expertise. While lacking consensus on the extent and variability of climate change, in 2001 the International Panel on Climate Change considered that such an increase may result in unstable weather patterns, increased temperatures, more frequent droughts, sea level rise, more frequent extreme weather events, reduced marine biodiversity and the wider distribution of certain insect borne diseases.

The impacts under consideration are complex and multi-factorial, with a number of scientists constantly evolving our understanding. None of this complexity is acknowledged in Gore’s presentation as he “connects the dots” as he sees them, whitewashing all scientific qualifications. For example, his use of the receding glaciers in Kilimanjaro as evidence of global warming fails to mention that this phenomenon has in fact been occurring since 1880, long before the significant increase in greenhouse gases.

The third key issue, given that governments around the world have largely accepted that climate change may be caused by human activities and that the impacts may be adverse and irreversible, is how do countries practically reduce greenhouse gas emissions?