there are a lot of ways to promote agriculture using desalinated seawater, even if you only use evaporation methods. Keep the water in the system by using greenhousing.
Australia could probably end up utilizing its whole coast for 10km inland if it wanted to. keep to the Fen Causeway
re flooding lake eyre, it would probably be an environmental disaster, and my climate scientist friend says it would have negligible effect on rainfall (consider the rainfall north of perth, which has a large ocean providing the aforementioned evaporation).
Using evaporative desal in greenhouses is a great idea, and one I've promoted to farmers in the past. But it's too far out for them and too far in for scientists. And it only makes sense for locally scarce foods (e.g. bananas in WA) given the cost of greenhouses over fields.
