This is an idea I've had in my head for a while but finally put some writing down on it in between my NBM writing.
I wanted to have Europeans reach Australia to discover a lush, jungle world, very similar to the Amazon and write an alternate history from there. The actual POD occurs very far in the past, but once it happens, Australia is the only area affected and the 'butterfly net' will apply until contact by Indonesians around 1100-1300. Though a larger butterfly net will apply for the rest of the world until European contact.
Please let me know if you all think this is a bit too ASB for a POD, as I know keeping humans off Australia may seem fairly implausible. But if enough people like the idea, then I'll carry on with it.
Anyway enough of that and now here is the first step in Paradise Down Under.
1. In The Beginning
55,000 BC [1]
Picture if you will, South East Asia as it was thousands of years ago. The level of oceans was far smaller and much of modern day Thailand and western Indonesia is linked into one large continental mass known as Sunda. Across from this New Guinea and Australia are linked to make the continent of Sahul. In between lie the rest of the Indonesian islands and a series of straits.
Groups of early human settlers have been migrating south east from India and are beginning to explore the seas and straits between the two continents. One of the earliest groups makes the long 90 mile sea journey to Sahul’s western coast, but intense storms batter the fleet of small ships, sinking most of them. The survivors make land, but only eke out an existence before all dying out. Another migration occurs, but is also hit with storms and the fleet is pushed north towards Sulawesi. These early humans give the ocean we know as the Timor Sea and Eastern Indian Ocean, the name Raging Waters. They tend to avoid it and migration is focused north and eastwards. Over time humans make it to western New Guinea, but they avoid travelling southwards. By the time they have expanded to any significant degree the last glacial period is coming to an end and the seas are rising.
6000 BC
The part of Sahul that would be Australia has remained unsettled by humans for a long time, except for a few small enclaves south of modern day Timor. The rising sea levels have been isolating the human settlements throughout South East Asia and by 6000 BC Australia’s land bridges to New Guinea have been severed. Australia remains an abundant land of lush flora and fauna. Vast plains of savannah and light woodlands make up much of the west, with flocks of giant kangaroos and thunder birds [2]. In the centre of the island continent is a vast jungle teeming with life. This jungle stretches from north to south and reaches all the way to modern day New South Wales. This jungle is teeming with life, giant wombats are hunted by marsupial lions, the Quinkana crocodile is the apex predator of the jungles, while massive snakes prey on the unwary
In the northeast are rock lands and heavy woods where the Varanus goanna claims a status as the largest predatory lizard at 7 metres. Koalas one third bigger than their modern cousins climb the trees and many other giant birds and reptiles exist. This is an Australia untouched by human hands, with a vast ecological eco-system and fauna which continues to flourish. The marsupial, birds and reptiles retain their immense size and Australia does not undergo desertification. Welcome to the southern continent that has remained untouched by human hands for millennia, welcome to Paradise Down Under.
[1] Around this time is when Australia is believed to have first been settled. A large part of the reason Australia is a desert is thought to be due to many of these settlers starting large forest fires for clearing land and moving game. This got out of control and destroyed the whole eco-system, resulting in most of Australia as a desert. In addition this also wiped out much of the mega fauna and mass extinctions of all kinds of plant and animal life. Since the goal of this TL is too have a lush Amazonian style Australia, the easiest way to do this is too restrict the human settlement of the continent.
[2] A large carnivorous, flightless bird, official classification Dromornis stirtoni. This bird was the biggest flightless bird that ever existed.