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Climate Change and Australian Bushfire Property Losses
McAneney, J., Chen, K. and Pitman, A. 2009. 100-years of Australian bushfire property losses: Is the risk significant and is it increasing? Journal of Environmental Management 90: 2819-2822.

In his book An Inconvenient Truth, Al Gore (2006) displays a graph that shows a steady increase in major wildfires over the prior five decades (1950-2000), of which he says that "the same pattern is found on every continent.

What was done
McAneney et al. assembled data that can be used to evaluate Gore's claim as it pertains to Australia. Their primary source of information for this project was "Risk Frontiers' disaster database of historic building losses -- PerilAUS -- which provides a reasonably faithful testimony of national building losses from 1900," with additional information being provided by the Insurance Council of Australia's database of significant insured losses.

What was learned
The three researchers note that "the annual aggregate numbers of buildings destroyed by bushfire since 1926 ... is 84," but that "most historical losses have taken place in a few extreme fires." Nevertheless, they state that "the most salient result is that the annual probability of building destruction has remained almost constant over the last century," even in the face of "large demographic and social changes as well as improvements in fire fighting technique and resources."

To ensure that this fact comes through loud and clear, they restate it again and again and again and again: (1) "the historical evidence shows no obvious trend," (2) "the likelihood of losing homes to bushfire has remained remarkably stable over the last century with some building destruction expected in around 55% of years," (3) "this same stability is also exhibited for the bigger events with an annual probability of losing more than 25 or 100 homes in a single week remaining around 40% and 20% respectively," and (4) "the statistics on home destruction have remained obstinately invariant over time." What is more, McAneney et al. state that "Australia's population has increased from around 4 to 20 million over the last century," and, therefore, that we might logically have expected "the likelihood of bushfire losses to have increased with population or at least with the population living immediately adjacent to bushlands." However, they once again state what their data clearly reveal, i.e., that this expectation "is not so."

What it means
The data from Australia provide a stunning repudiation of Al Gore's Inconvenient-Truth claim of there having been a "steady increase in major wildfires" on every continent over the last half of the 20th century. They also repudiate any extension of his claim backward in time; and McAneney et al. feel confident in extending the repudiation forward in time as well, concluding in the final sentence of their paper's abstract that "despite predictions of an increasing likelihood of conditions favoring bushfires under global climate change, we suspect that building losses due to bushfires are unlikely to alter materially in the near future."

Gore, A. 2006. An Inconvenient Truth: The Planetary Emergency of Global Warming and What We Can Do About It. Roldale, Emmaus, Pennsylvania, USA, p.228-229.

Reviewed 21 October 2009