Trend Maps
Forest evaporation is separate (not wholly independant), so this just covers pan evaporation.
Shows proof of the evaporation process is slowing down. So that is occuring all over Australia except the sub tropic area which is usually hot and dry, and is a desert. So that sub tropic region is the only region where evaporation is speeding up and that is because through climate change it is becoming hotter and drier still.
We have to assume Australia is still losing forests (which it is and has accelerated by 70% within the last few years). So you can connect the dots, but you can't eliminate any other theories if there is any. Warming oceans alone can create similar circumstances, and the ocean can just heat up from the greenhouse effect alone.