John McAneney

Evaluation of the AR4 Climate Models’ Simulated Daily Maximum Temperature, Minimum Temperature, and Precipitation over Australia Using Probability Density Functions

Abstract The coupled climate models used in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change are evaluated. The evaluation is focused on 12 regions of Australia for the daily simulation of precipitation, minimum temperature, and maximum temperature. The evaluation is based on probability density functions and a simple quantitative measure of how well each climate model can capture the observed probability density functions for each variable and each region is introduced. Across all three variables, the coupled climate models perform better than expected. Precipitation is simulated reasonably by most and very well by a small number of models, although the problem with excessive drizzle is apparent in most models. Averaged over Australia, 3 of the 14 climate models capture more than 80% of the observed probability density functions for precipitation. Minimum temperature is simulated well, with 10 of the 13 climate models capturing more than 80% of the observed probability densit...

Regional ash fall hazard I: A probabilistic assessment methodology

Volcanic ash is one of the farthest-reaching volcanic hazards and ash produced by large magnitude explosive eruptions has the potential to affect communities over thousands of kilometres. Quantifying the hazard from ash fall is problematic, in part because of data limitations that make eruption characteristics uncertain but also because, given an eruption, the distribution of ash is then controlled by time and altitude-varying wind conditions. Any one location may potentially be affected by ash falls from one, or a number of, volcanoes so that volcano-specific studies may not fully capture the ash fall hazard for communities in volcanically active areas. In an attempt to deal with these uncertainties, this paper outlines a probabilistic framework for assessing ash fall hazard on a regional scale. The methodology employs stochastic simulation techniques and is based upon generic principles that could be applied to any area, but is here applied to the Asia-Pacific region. Average recurrence intervals for eruptions greater than or equal to Volcanic Explosivity Index 4 were established for 190 volcanoes in the region, based upon the eruption history of each volcano and, where data were lacking, the averaged eruptive behaviour of global analogous volcanoes. Eruption histories are drawn from the Smithsonian Institution’s Global Volcanism Program catalogue of Holocene events and unpublished data, with global analogues taken from volcanoes of the same type category: Caldera, Large Cone, Shield, Lava dome or Small Cone. Simulated are 190,000 plausible eruption scenarios, with ash dispersal for each determined using an advection–diffusion model and local wind conditions. Key uncertainties are described by probability distributions. Modelled results include the annual probability of exceeding given ash thicknesses, summed over all eruption scenarios and volcanoes. A companion paper describes the results obtained for the Asia-Pacific region

100-years of Australian bushfire property losses: Is the risk significant and is it increasing?

This study examines the bushfire (wildland fire) risk to the built environment in Australia. The most salient result is that the annual probability of building destruction has remained almost constant over the last century despite large demographic and social changes as well as improvements in fire fighting technique and resources. Most historical losses have taken place in a few extreme fires which if repeated are likely to overwhelm even the most professional of fire services. We also calculate the average annual probability of a random home on the urban-bushland interface being destroyed by a bushfire to be of the order of 1 in 6500, a factor 6.5 times lower than the ignition probability of a structural house fire. Thus on average and if this risk was perceived rationally, the incentive for individual homeowners to mitigate and reduce the bushfire danger even further is low. This being the case and despite predictions of an increasing likelihood of conditions favouring bushfires under global climate change, we suspect that building losses due to bushfires are unlikely to alter materially in the near future.

'Shelter-in-place' vs. evacuation in flash floods.

This paper examines the circumstances in which a ‘shelter-in-place’ strategy may be a viable alternative to evacuation during flash floods. While evacuation remains the dominant strategy for a range of hazards, a review of the literature suggests growing awareness of the dangers associated with late evacuations and some limited consideration of shelter-in-place options. This study examines the feasibility of a shelter-in-place strategy for flash floods in Australia through: a review of literatures on evacuation, ‘sheltering-in-place’ and flood fatalities; an analysis of Australian flash flood fatalities and injuries; and interviews with flood and emergency managers. The results demonstrate that the majority of flash flood fatalities (75.7 per cent) have occurred outside when people have entered flood waters in a vehicle or on foot for a range of reasons, including to continue their intended travel, engage in recreational pursuits, continue their work, and evacuate or carry out a rescue. Interviews with emergency managers confirm that while shelter-in-place may not be the preferred option, the strategy may need to be implemented for flash floods when, due to the limited warning times, evacuation is not possible.

How can residents know their flood risk? A review of online flood information availability in Australia

Abstract Widespread flooding across eastern Australia between November 2010 and February 2011 has again highlighted the countrys susceptibility to natural disasters. The floods have also triggered discussion about flood awareness, risk information, and the role and responsibility of governments, insurance providers and residents. This paper examines the availability of flood hazard information on local government websites in Australia; it was completed in mid-2010 before the 2010–2011 flooding. The quality and accessibility of information is discussed, as are variations based on state and population size of different Local Government Areas (councils). Particular attention is given to those areas that experienced recent flooding, as well as to known areas of concentrated risk. There are large gaps in information availability, with less than 50% of councils provided flood risk information. A higher percentage of councils in the more populous states, some of which also have higher flood risk, provide information than those in less-populous states. Of those councils with a recognised flood risk, 67% provided flood information online.

Is the allocation of resources towards mitigation and response to fire in Australia optimal

Australia invests significant resources to address the risk of fire in all its forms. This study asks the question: is the current investment strategy cost‐effective? This question was approached in two ways: first, through a cross‐sectional study of fire statistics from other developed countries and, second, through a structured expert judgment exercise. The former found no significant relationship between the level of investment and losses from fire, suggesting that other factors are responsible for the observed inter‐country variance in fire losses. All the respondents to the structured expert judgment exercise perceived no net economic benefit would be achieved from increasing investments in prevention and response and most indicated net benefits from reducing this investment. The results of the expert judgment analysis, when considered alongside the equivocal international comparisons and fire service efficiency gains achieved in some parts of England and Wales, raise doubts about whether the allocation of investments in mitigation and response in Australia is truly risk‐informed.

Valuing new product development and analysing license agreements for intellectual property

Strategic investments in research and development (R&D) possess challenging features for valuation: the relationship between research effort and a marketable product is highly uncertain and there is always the possibility for some exogenous event or competitor behaviour to render the whole effort valueless. The R&D project studied here concerns the breeding of new fruit varieties in a programme jointly funded by a research provider and an international marketing company. The breeding programme is modelled on the premise that the R&D comprises a series of lotteries – in the sense that the outcome in each evaluation phase is probabilistic – and that the final prize in this lottery is a call option, in this case the option-to-market accorded the marketing company. The model provides a framework for optimising contractual arrangements between the joint venture parties and encouraging profit maximisation.

Ability of global climate models at a regional scale over Australia

We evaluate the coupled climate models used in the fourth assessment report of the Intergovernmental Panel on Climate Change (IPCC). Our evaluation is focused on twelve regions of Australia for the daily simulation of precipitation, minimum temperature and maximum temperature. We base our evaluation on Probability Density Functions (PDFs). We introduce a simple quantitative measure of how well each climate model can capture the observed PDFs for each variable over Australia. Across all three variables, the coupled climate models perform better than we expected although one model is clearly flawed in simulating maximum temperature. An overall ranking of the climate models, for the three variables is presented. We therefore provide guidance on those climate models that are skillful over Australia, providing direction on those that should be used in impacts assessments where those impacts are based on precipitation or temperature.