New research reveals how rapidly growing regions in Queensland can draw inspiration from biodiversity and carbon offsetting initiatives to effectively achieve water quality targets.
Led by The University of Queensland‘s Joseph McMahon, the study, in collaboration with the Reef Catchments Science Partnership, delves into enhancing the reliability of water quality offsets – a pivotal factor in safeguarding the health of the Great Barrier Reef. This study particularly focuses on areas experiencing population growth, such as Cairns and Mackay, offering compelling insights for sustainable development.
“Water quality offsets are designed to counterbalance industrial pollution by reducing emissions elsewhere, often from agricultural sources,” Mr McMahon said. “However, our study highlights substantial uncertainties in the effectiveness of this approach, especially in accurately measuring pollution reductions from agricultural land use changes.”
“In this study, we summarised these uncertainties and estimated the demand for water quality offsets from sewage treatment plants – the largest industrial emitter of total nitrogen in Great Barrier Reef catchments – until 2050.
“We also discussed the implications of both on the ability of offsetting to counterbalance industrial emissions in catchments where water quality has a large influence on the Reef’s health.”
Researchers predict that sewage treatment plants in Cairns will need a substantial volume of water quality offsets by 2050, while the immediate demand for offsets in Mackay is relatively smaller. This finding underscores the urgent need for proactive measures to safeguard water quality in these regions.
“It’s particularly important that water quality offsets in these catchments have a high integrity to ensure increased industrial pollution is adequately counterbalanced and important water quality targets for the Reef are met,” Mr McMahon said.
“Water quality offsets could help industries like sewage treatment plants comply with regulations while also protecting the Reef, but uncertainties in measuring their effectiveness pose challenges.
“Some examples of water quality offsets these regions could employ include improved crop management practices and riverbank revegetation to improve water quality in waterways in Reef catchment areas.
“In general, if agricultural offsets are implemented near industrial emissions and have a high certainty of effectiveness, they are more likely to have a high integrity.
“This allows industries to comply with regulations while protecting the Reef from pollution linked to population growth.
“This approach provides a balance between scientific rigor and policy workability until further research into pollution hotspots and transport pathways can address some of the uncertainties.”
Journal reference:
- J.M. McMahon, R.D.R. Turner, J.C.R. Smart, J.S. Shortle, I. Ramsay, D.F. Correa, D. Chamberlain, Y. Mao, M.St.J. Warne. Offset integrity reduces environmental risk: Using lessons from biodiversity and carbon offsetting to inform water quality offsetting in the catchments of the Great Barrier Reef. Science of The Total Environment, 2024; DOI: 10.1016/j.scitotenv.2024.175786