Paddy fields aren't the only way to grow rice, you can do rows and flood soil alongside, you can do upland style dry fields rice planting.

I guess the point of the experiment was with climate and increasing flooded landscape (like the fens?) But the risk would be salt incursion as much as anything else.

If it's climate (temperature) alone, it didn't need paddy fields. I think a lot of Australian rice is irrigated but not full flooded fields, or a reduced flood compared to traditional approaches. More amenable to massive fields and a water storage system. Recently saw a cotton farm at St George and the (huge!) fields are groomed with a laser level to control for irrigation flow, I think they do the same for rice, when it makes sense.