While a simple linear relationship between inflow and (SWWA) rainfall is sufficient to describe much of the variability in observed inflows, the most recent data confirms that the relationship appears to have changed after 1976, with less inflow for a given rainfall amount. The role of temperature in this changed relationship has been investigated but we find that any apparent correlations reflect the fact that rainfall and temperature tend to be inversely related and that temperature and inflow data exhibit long-term variability. When these factors are accounted for there

is no evidence that local temperature changes have any direct effect on inflows. This suggests that other explanations for the changed relationship between rainfall and inflows are more likely. For selleck chemicals llc AZD6244 ic50 example, the combined effects of changes in timing of rainfall events throughout the year, the absence of very heavy rainfall events and long-term changes in the physical character of the catchments – most likely changes to ground water levels. As was found in analyses of previous climate model experiments, the latest set of climate model results (CMIP5, RCP8.5) all project a decline in annual rainfall by the end of the century accompanied

by relatively large uncertainty. Some models (ACCESS1-3, BNU-ESM, CMCC-CESM, IPSL-CM5B-MR, IPSL-CM5B-LR, MPI-ESM-LR and NORESM1-M) exhibit time series that exhibit similarities to the observed SWWA time series in terms of a late 20th century decline. This confirms early interpretations that suggested that both natural variability and the enhanced greenhouse effect have contributed to the rainfall decrease. The climate change projections Acesulfame Potassium continue to indicate a pessimistic outlook for rainfall – a finding consistent with those presented in previously published studies. Despite the consensus amongst the models, there

is still a relatively wide range in the magnitude of the projected decline by the end of the century. Given this range, plus the fact that we have only considered the results associated with a single emissions scenario, we have made no attempt to deal with this uncertainty. The fact that the CMIP5 projections do not differ substantially from previous model projections suggests that further modeling experiments will not yield much more extra information. However, some climate-related questions still deserve attention. For example, are the projected rainfall decreases accompanied by similar changes to mean sea level pressure patterns and the frequency of rain-bearing systems? Is it possible to narrow the uncertainty in the projections by discriminating between models and/or downscaling the result? Otherwise it is apparent that changes in the rainfall/inflow relationship could be just as important, if not more so, than changes to rainfall.