The Geography of Tasmania Explained

Down in the bottom right corner of the world map, just underneath Downunder lays the island of Tasmania, an island shrouded in mystery and natural wonders, full of mountains and untouched temperate rain forests. The island belongs to the Commonwealth of Australia, making up its 7th and smallest state, both by land area and population. Tasmania is generally considered a mountainous Island, despite its tallest mountain only standing at 1600 meters above sea level.

The unique stone formations with tall and slender vertical diabase columns, still make it worth a sight, however. Surrounding this peak are many of Tasmania’s National Parks, which all together put over 40% of the island’s landmass under protection. Most of these cover the large central plateau whose outliers cover most of the island.

Neighboring to the east lays a distinct lowland area where most of the fertile soils can be found, and further east yet another mountainous area called the Ben Lomond bioregion fills the gap to the eastern shore. This east west separation of mountains and lowlands has a peculiar effect on the island, when taking the global atmospheric circulation patterns into account. Earth’s atmosphere can be imagined as a giant system of conveyor belts, which are constantly churning and turning air around.

These loops are called cell’s and of the 3 major ones which control the atmosphere, the Ferrel Cell between the 30th and 60th degree latitude creates a constant south ward wind towards th e poles. Since our earth is spinning, and different latitudes spin at different speeds, the Coriolis Effect gives this cell strong eastward drag, causing a violent and never-ending supply of winds to hit Tasmania and its surrounding waters. These winds, called the roaring forties are a blessing for eastwards sailing boats and the reason why most circumnavigations are directed this way, but they also bring a lot of precipitation with them when touching down on Tasmania.

Coming back to the large central highlands which are blocking much of this precipitation from reaching the eastern shores, a very much divided climate can be found across the island. The town of Strahan on the western coast of Tasmania for example receives around 231 rain days per year whereas its eastern counterpart Swansea only experiences 117 rain days due to the mountains holding back much of the rainy clouds. Despite the moderate temperatures in Tasmania, the high precipitation in the western parts has created a diverse temperate rainforest landscape with many diverse plant and animal species.

Often called the “Gondwana temperate rainforest”, the forested mountains of Tasmania’s west have many plants which are assumed to have populated the ancient mega continent Gondwana which combined the continental shelves around 600 million years ago. Towering “Eucalyptus regnans” with heights of over 100 meters and millennia old Huon pine trees which can live for up to 2000 years are both endemic to Tasmania and are only a tiny fraction of the unique flora found in those forests. Fauna-wise, Tasmania also has a whole array of species to offer, which have many similarities to their Australian neighbors but due to a process called island-gigantism, they are often a lot larger.

The best-known example of this are the giant platypus of Tasmania which can grow up to 3 times larger than their Australian ancestors, or the Tasmanian giant Freshwater Crayfish which lives in the islands rivers and grows up to become the largest species of freshwater lobster in the world. Other unique species are the Tasmanian Devil which has the strongest bite force per body weight of the entire animal kingdom and can only be found on the remote island. Similarly, to Australia, Marsupial mammals, animals which raise their young in belly pouches, are dominating the animal kingdom and the strong overlap between mainland Australian and Tasmanian species can be drawn back to the two landmasses being separated for only a very short while from a geologist’s point of view.

During the peak of the last ice age around 20. 000 years ago, much of the world’s water reserves were locked up in the glaciers of the globes far north and south, lowering the sea levels to 120 meters below today’s level. Examining the Bass strait which connects the two lands, you can see that most parts only have a depth of 50 to 70 meters, meaning that during the peak of the last ice age, there was a relatively wide land bridge connecting them.

With the roaring 40’s pushing waves into the Bass strait, this shallow depth makes it one of the most dangerous sea routes in the world. When the fast moving deep-ocean waves from the Indian Ocean encounters the ridge of the bass strait, the increased friction from the seabed slows down and compresses the wave causing them to tower to heights of up to 18m or 60 feet. Ships entering the bass strait are not just challenged by the rough waves however, since sand banks and reefs, semi submerge rocks and tidal waves are adding another layer of complexity to the crossing.

Thousands of sailors have lost their life in the past centuries and the shores around King Island, which marks the western entrance to the strait is the unfortunate resting place of hundreds of shipwrecks. Calmer waters are found on the island itself with 3 major river networks draining the majority of the rainy inland into the oceans and straits surrounding it. Notably the Gordon River in the west, the River Derwent in the southeast and the South Esk river in the north cover nearly 40% of the island with the South Esk river also having the longest course.

These rivers are the backbone of the people living on Tasmania by providing invaluable irrigation water in the dryer east, as well as vast hydroelectric potential, which today covers over 90% of the state’s energy demands with other renewable sources like solar and wind covering the remaining 10%. With plans to cover 200% of the island’s energy demand with renewable electricity by 2040, a new energy storage facility in the form of a large pumped hydro station which allows uphill storage of water for later retrieval and energy production are currently being discussed, but the economic and environmental implications are slowing the process of this project. The energy would be designated for mainland Australia, meaning that large scale infrastructure, crossing the rough Bass Strait would be needed, which raises the alarm bells of conservationists and environmentalists across the island.

Regardless of whether environmentalist or economic goals assert themselves, Tasmania is undoubtedly a peculiar and unique geographical marvel. If you want to learn more about other extremities of the world’s continents, you should check out this video about the geography and people of Lapland at the most northern tip of Europe, or this video covering Tasmania’s western counterpart, the southern tip of South America or better called Patagonia. If you want to see more videos like this one, be sure to subscribe and leave a like.

Cheers.