You know an issue has gone too far when it becomes a reason for everything. Greenhouse emissions have just about reached that place.
A report in today’s Courier Mail says that the Traveston Dam should not go ahead because it will produce 400,000 tonnes of CO2 per annum.

The University of Technology Sydney report said the Queensland Government had not accounted for thousands of tonnes of greenhouse gas emissions which would be produced each year by pumping up to 70 million tonnes of water from the dam to Brisbane.

The report by the Institute for Sustainable Futures doesn’t appear to be publicly available, but according to the CM it supports desalination rather than a dam.
Apparently the emissions are generated in transporting the water from Traveston to Brisbane, and also from the surface of the dam itself.
This is the sort of report where you wouldn’t want to rely on the cover page for your decision making. The first issue that comes to mind is why they would be pumping the Traveston water to Brisbane. There is plenty of growth due to occur north of Brisbane that will need this water.
You’d also want to be sure that they were comparing apples with apples. For example, the desalination plant that is being built at Tugun is 94 kilometres from where I live by road, and Traveston is 173. Assuming that I represent “Brisbane”, then what are the relative emissions between pumping water to me from one spot versus the other? What other sites have they considered for desal?
I’m not sure how the dam surface will create greenhouse emissions, but presumably it has something to do with organisms in the water releasing CO2 and with the decay of plants drowned by the dam releasing methane. But to make this claim stick, they would need to show that there would be a net increase in these emissions over the business as usual scenario. That is, that the dam would create more organisms to release CO2 than would live in the un-flooded dam catchment, and that decaying vegetation would release more methane decaying under water than it would decaying in the air.
The state government’s answer to the charge is to say that they are planting 2000 ha of timber to abate the emissions. Makes you wonder how many planets we will need for all the trees being planted to allow us to meet business as usual scenarios of greenhouse emissions.
I hope this forest isn’t being planted in the dam catchment. Trees need water too, and one of the issues with catchment management is the effect trees have on water inflows and hence the water available to human consumers.