From the get-go Australian politicians knew that there may be trouble ahead. This below, from The Greenhouse Effect: Living in a Warmer Australia by Henderson-Sellers and Blong [review by New Scientist here] gives a taste of that (though to be clear, the authors, not Hawke and Button, are raising the possibility).
On the morning of Monday 30 January 1989, the ABC 7.45am news reported the Prime Minister, Mr Bob Hawke, had begun an overseas trip to Korea, Thailand, India and Pakistan, with the primary aim of promoting Australian exports, particularly coal, iron ore and agricultural products. Juxtaposed with this report was one describing Senator John Button’s encouragement of Japanese investment in Australian forests designed to safeguard our timber resources. The viability of these economic moves may also be subject to the greenhouse effect. Australian exports of fossil fuel, particularly coal, may be restricted by increasing international pressure to try to reduce the emission of carbon dioxide. (emphasis added)
(Henderson-Sellers, A. and Blong, R., 1989:3)