fester, good question. Farmers are constantly reminded that we only constitute 2.7% of GDP and how much better the environment will be without us. How easy it would be to import all our food.

The looming shortage of fresh produce may change these perceptions. That and the fact that even though farming is a small proportion of GDP it has a large share of export income(30% from memory).
I can't see our nation starving itself for extra income, and in reality most of our exports are bulk low priced commodities. As the world population grows and requires more resources they may have no alternative but to buy value added product from Australia instead of us simply providing bulk ie. flour/bread/breakfast cereal instead of wheat. Our unemloyment is low and we will need more people to achieve such an outcome. We could create more income without sending more food.

I dont think we'll starve either, but what help will Australia be to the rest of the world? I disagree with your comment:

"Our unemloyment is low and we will need more people to achieve such an outcome."

Australia has quite a large unutilised workforce. Are they not fit for a purpose? Remember also that a large labour force is currently needed to satisfy the logistical demands of population growth.