65,000 years ago the world was going through an Ice Age. The climate in Sahul was different to what we know today. The weather was colder and until about 40,000 years ago there was more rainfall, so there was more freshwater around compared to today. For example, until about 40,000 years ago there were rivers in the Channel County, which has since become a very dry area. Also, there was a great freshwater lake where the Gulf of Carpentaria is today. It is this abundance of freshwater that made it possible for people to reach every part of the country.
It is difficult to know for sure how things were back then, but scientists think the climate was a lot more variable than it is today: there were periods of warmer temperatures when there was high rainfall followed by periods of colder weather when there was low rainfall. These two weather systems would switch back and forth in an unpredictable way.
Some scientists think that due to these unpredictable conditions the number of people back then could not grow very large and that our ancestors lived in small groups scattered across the country. Other scientists disagree with this and think that there were regions where water was always abundant and that allowed a great number of people to thrive.
The vegetation was of course also affected by temperature and rainfall changes. Scientists think that when people first arrived in today’s Queensland the country was partly covered in grasslands and partly in dry forest. They think that much of the south of the country was desert back then.