Why is Australia so overwhelmingly dry when nearby places like Papua New Guinea, New Zealand, Indonesia, and Tasmania are all so wet and lush?
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It has almost nothing to do with mountains. It has to do with global air flow, trade winds, Hadley cells, and the like. South America has mountains AND desert.
There is a permanent low pressure area over the equator. The Sun is generally most intense over the equator, and heats the Earth; the warm air rises and cools, dumping all it’s moisture. Thus, lush tropical rain forests.
The cold, dry air makes its way South, and sinks. As it sinks, it warms up. Now you have warm, dry air falling to Earth, ready to soak up moisture like a sponge, and that air makes contact with the Earth at about the 25-30S latitude: right through the heart of Australia. It also forms the Kalahari desert in Africa, and the Atacama in South America.
Note: Some of the rising equatorial air goes North and sinks at the 20-30N latitude, forming the Sahara, the desert regions of the South West United States, and others.
Other people have touched on the science, but I think a lot of people don’t realise Australia is a HUGE continent. Australia and the USA are similar in size, in terms of land mass.
Northern parts of Australia (such as Darwin and surrounds, Far North Queensland, etc) are like Papua New Guinea & Indonesia in being wet and lush, but travel thousands of miles south to where the fires are and the climate/landscape is completely different.
Your question is a bit like asking why America is so hot and dry if nearby Canada is cold and snowy. Or why America is so snowy and cold when nearby Mexico is tropical.
*edited for clarity
I can’t answer your question, but FYI, NZ is ready to catch fire pretty much all summer.
[These signs](https://resources.stuff.co.nz/content/dam/images/1/o/5/n/l/4/image.related.StuffLandscapeSixteenByNine.1240×700.1o5mon.png/1517378202799.jpg) are common on main rural roads.
and there is a govt advertising campaign to spread the message:
https://www.sciencelearn.org.nz/resources/745-the-fire-danger-sign-and-bernie
You’re not even allowed campfires when camping! 🙁
Australia is mainly in an area of the earth called a “subsidence region.” This basically means that there is a lot of air that is sinking from higher up in the atmosphere. This air is also dry, so when it sinks it gets warm and dry and so you see mainly desert in Australia. These regions are generally from 15-30’ N or S of the equator.
Open Google Maps with satellite view and you’ll generally see lots of deserts in these places. The Sahara, American Southwest, etc. This is a generalization but holds mostly true as there are other reasons deserts exist.
Papua New Guinea and Indonesia are near/on the equator where it is far wetter and the air is rising instead of sinking (if you ask why that is another can of worms I can try and explain).
New Zealand and Tasmania are farther south than these subsidence regions and benefit from westerly winds that bring moisture and energy from the equator.
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