Search

We evaluated the uncertainty associated with secondary pollutants formation due to different chemical mechanisms in photochemical modelling. The CMAQ modelling system was utilized in conjunction with CB6R3, SAPRC07, and RACM2 chemical mechanisms and compared the concentrations of various chemical species, including ozone (O3) and particulate matter (PM2.5). Using datasets from ambient monitoring stations, we assessed the performance of each of the mechanism in summer and winter. The concentrations of various chemical species predicted by the three mechanisms varied significantly. The differences are more evident in summer than in winter for most of the species, except for hydrogen peroxide (H2O2), methyl hydroperoxide (MEPX), and Secondary Organic Aerosol—Anthropogenic. We observed that the summer daytime O3 predictions showed reasonable peaks at the three air quality monitoring sites, but the nighttime values under-predicted for all three mechanisms. In the winter, all three mechanisms tend to under-predict O3. Differences in the mean O3 values (bias) at the different sites, for the different seasons, are consistent with corrections made to previous modelling studies that modified KZMIN. PM2.5 predictions with RACM2 were slightly better. The dominant PM2.5 species in summer were sulfate and SOA-Bio, which may be attributed to non-mobile sources in the region, while NO3 became dominant in winter due to more favorable conditions for forming this species, including lower temperatures and an elevated NH4 to SO4 ratio. We concluded that the differences in O3 and PM2.5 predictions between the three mechanisms are significant, implying that when developing strategic and management actions are based on modelling, the most appropriate mechanism should be considered. [ABSTRACT FROM AUTHOR]

An increase in the frequency of severe fire events, as well as a growing interest in wildfire mitigation strategies, has created a demand for skilled managers of landscape fire and a better community understanding of fire behaviour. While on-ground experience is essential, there is potential to substantially enhance training and community engagement with explanatory simulations. Through this work, we explore landscape fire behaviour as a complex system where understanding key behaviour characteristics is often more important and achievable than prediction. It is argued that this approach has particular value in Northern Australia, where fires burn across vast and sparsely inhabited landscapes that are largely under Indigenous ownership. Land and fire management in such complex cross-cultural contexts requires combining traditional and local knowledge with science and technology to achieve the best outcomes. We describe the workings of the model, a stochastic cellular automata fire behaviour simulation, developed through a participatory modelling approach for Northern Australia; the outputs generated; and a range of operational applications. We found that simulation assisted training and engagement through the development of an understanding of fire dynamics through visualisation, underpinned by landscape data sets, and engaging a culturally diverse set of land managers in discussions of fire management. We conclude that there is scope for a broader use of explanatory fire simulations to support development of shared understandings of fire management objectives. [ABSTRACT FROM AUTHOR]

Insect outbreaks are natural phenomena that play a critical role in the development, senescence, and rebirth of forests. However, the damage caused by large-scale epidemics can have landscape scale consequences that are often poorly understood. The recent mountain pine beetle (MPB) outbreak in Canada has impacted a record >18.5 million hectares of pine forests, placing forest values at risk and significantly impacting forest-dependent communities within the region. To assess this impact, an ecosystem service-based approach was applied. Based on land cover information and monitoring data, four ecosystem services were assessed and mapped: merchantable timber, water provisioning, aboveground carbon storage, and vegetation diversity (supporting habitat). Timber is the most impacted provisioning ecosystem service followed by water provisioning, with peak stream flow in affected watersheds being positively related to mortality percent. Effects on carbon storage are substantial, with 20% of total timber aboveground carbon in dead pine trees. These effects may be mitigated, however, by the growth response of residual live trees and forest regeneration. The potential vegetation diversity showed a positive response to MPB-caused tree mortality. The results of our study may help with setting management priorities in response to large-scale biotic damage in forests in British Columbia and elsewhere. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper examines the economic potential for fire management to provide offsets to carbon markets in the savannas of northern Australia. Long-term field trials in Australia's savannas have quantified greenhouse gas (GHG) emissions abatement resulting from improved fire management. However, little is known about the economic potential of fire management projects or the locations where projects might be economically viable for providing GHG offsets. A benefit-cost analysis of fire management for GHG offsets is presented here, which includes spatially explicit estimates for GHG abatement under three assumptions of management efficacy (conservative, empirically based, upper potential). The total supply of GHG abatement is estimated under different prices and management efficacy assumptions, and areas that pass the benefit-cost analysis are identified. At the Australian Government's carbon price of A$23 per metric tonne of carbon dioxide equivalents (CO2-e), fire management would be economically viable across 51 million hectares, all within the higher monsoonal rainfall regions of northern Australia, abating 1.6 million tonnes of CO2-e per year. These estimates suggest that fire management projects can contribute to GHG abatement targets and be financially viable across large areas of northern Australia. Additional benefits are anticipated from these projects for biodiversity conservation, livelihoods for indigenous Australians and economic development in remote regions. [ABSTRACT FROM AUTHOR]

The article offers information on the West Arnhem Land Fire Abatement (WALFA) project in Northern Territory. It mentions that Indigenous rangers use prescribed burns throughout the 28,000 square kilometers of Indigenous-owned land on the Arnhem Land plateau to increase vegetation patchiness and make firebreaks. It states that renewed fire management on the plateau has been approximated to lessen emissions by about 147,000 metric tons every year.

Water quality impacts from agriculture and rapid land use change along Australia's coastline pose challenges for maintaining healthy marine ecosystems and community livelihoods. This article presents an agent-based model of an emissions trading scheme to regulate water quality, examining the effect of land use change and different cap levels on the performance of the market. Simulation results suggest that the cap-and-trade system facilitates the expansion of high-input horticulture while maintaining the overall cap level, and that tighter cap levels have income distribution effects. Heterogeneity of productivity influences trading price, volume traded and gains realised from trading; also small homogeneous trading populations produce a thin market; and trading benefits might not justify creation and maintenance of the instrument and effort required to participate. Novel contributions of this article are how cap-and-trade systems function within a landscape in transition, and also modelling the equity of how benefits of trading are distributed across the population. [ABSTRACT FROM AUTHOR]

Interconnected social and environmental systems are the domain of ecological economics, and models can be used to explore feedbacks and adaptations inherent in these systems. Agent-based modeling (ABM) represents autonomous entities, each with dynamic behavior and heterogeneous characteristics. Agents interact with each other and their environment, resulting in emergent outcomes at the macroscale that can be used to quantitatively analyze complex systems. ABM is contributing to research questions in ecological economics in the areas of natural resource management and land-use change, urban systems modeling, market dynamics, changes in consumer attitudes, innovation, and diffusion of technology and management practices, commons dilemmas and self-governance, and psychological aspects to human decision making and behavior change. Frontiers for ABM research in ecological economics involve advancing the empirical calibration and validation of models through mixed methods, including surveys, interviews, participatory modeling, and, notably, experimental economics to test specific decision-making hypotheses. Linking ABM with other modeling techniques at the level of emergent properties will further advance efforts to understand dynamics of social-environmental systems. [ABSTRACT FROM AUTHOR]