Water Journal : Water Journal September 2015
28 Opinion WATER september 2015 Managing the risks and resilience of the Murray- Darling Basin River systems into the future requires that the Basin Plan incorporate measures to adapt to the projected impacts of climate change on both trend and variability. There is sufficient quantitative knowledge available that indicates there are significant direct and indirect risks from climate change on water availability. Yet the current Basin Plan and associated programs do not properly address climate change and there are at least seven actions required to manage climate change and water inflow risks into the future. It is our view that the failure to use current knowledge on projected impacts of climate change in the computation for the Basin Plan’s sustainable diversion limits, or provision for systematic adjustment into the future, significantly increases the risks to the ecological heath of the river systems. It also increases the uncertainty to communities, who now have no clear policy setting or process to manage the anticipated changes in water availability into the future. We conclude that action is required to revise the Basin Plan (and the Water for the Future package) earlier than is scheduled for 2022. CLIMATE CHANGE IMPACTS AND STREAM FLOW RISKS IN THE BASIN Reduced water availability in the Basin due to climate change has been projected from the 1980s (Pittock, 1980; Palmer et al., 2008). The mid-latitude location makes the Basin particularly sensitive to climate-induced hydrological change (Palmer et al., 2008; Gallant et al., 2012; Grafton et al., 2012). Last decade, CSIRO projected scenarios for surface water availability in the Basin by 2030. The scenarios of ‘extreme wet’ – 7% more water, ‘median’ – 12% less, and ‘extreme dry’ – 37% less, exhibit great uncertainty (CSIRO, 2008). The higher or lower inflows increase down the river to the sea so that, for example, an extreme dry scenario could result in as much as a 69% fall in outflows. In this context it is imperative that relevant governments enact robust climate change adaptation measures to manage increased temperatures, changes in water availability and more frequent extreme events, among other impacts. The Federal Government has adopted a regulatory Basin Plan to manage water diversion limits, supported by other programs, notably the Water for the Future package that seeks to facilitate the reallocation and better management of water among consumptive and environmental users. Of fundamental importance is the failure of the current Basin Plan to incorporate projected climate change impacts in the assessment of the ‘sustainable diversion limits’ (SDL; SSCRRAT, 2013), which are critical mechanisms to give some level of confidence to water users and managers of the river health. SEVEN MAIN PROBLEMS FOR CLIMATE CHANGE ADAPTATION While Neave et al. (2015) suggest ways in which the current Basin Plan may be adjusted to manage climate change from 2022, all of the measures outlined fail to deal with the primary task, which is to have means to set and adjust the SDLs in line with the anticipated impacts of climate change. In their conclusion, Neave et al. (2015) admit this when they state: “Policy challenges remain, not the least of which is how reductions in water availability due to climate change could be shared between consumptive use and the environment”. We argue that no allowance has been made in the SDLs for long-term climate change to adequately partition water use adjustment for consumptive THE MURRAY-DARLING BASIN PLAN FAILS TO DEAL ADEQUATELY WITH CLIMATE CHANGE Our April issue featured a technical paper titled ‘Managing Water in the Murray-Darling Basin Under A Variable And Changing Climate’. The paper caused a bit of a stir and created dispute among Australian scientists. In this opinion piece Jamie Pittock, John Williams and R Quentin Grafton from the Australian National University state their case.
Water Journal August 2015
Water Journal November 2015