Antarctica is the coldest, driest and windiest continent on Earth, covered by a massive ice sheet that holds about 60% of the world's fresh water.
But beneath the frozen surface lies a mysterious and ancient landscape that has been hidden from view for millions of years.
Scientists have been using satellites and planes to map the features below the ice, such as mountains, valleys, lakes and rivers.
These features can tell us about the history of Antarctica and how it might change in the future as the planet warms.
A land of ice and fire
KEREM YUCEL/AFP via Getty Images
One of the most intriguing regions under the ice is called Highland A, located in East Antarctica. It covers about 32,000 square kilometers and lies around 2 kilometers below the ice sheet.
It was first discovered in 2011, but a new study published in the journal Nature Communications has examined it in more detail for the first time.
The study, led by Professor Stewart Jamieson from Durham University in the UK, used satellite data and radar imaging to reveal that Highland A consists of three distinct landscape blocks, ranging from 121 to 173 kilometers long.
Between the blocks are two large and deep valleys, which were likely fjords carved by glaciers in the past.
The researchers also found evidence of volcanic activity in the region, such as lava flows and volcanic cones.
They estimated that the landscape formed between 35 and 90 million years ago, during the Cretaceous period, when dinosaurs roamed the Earth and Antarctica was a lush swamp.
According to Professor Jamieson, the landscape of Highland A is unique and unlike any other place in Antarctica.
He explained that understanding the features below the ice can help us predict how the ice sheet will behave in the future.
He said that the detailed features of the landscape can reveal the past behavior of the ice sheet, which is important for modeling and predicting its future response to climate change.
The Antarctic ice sheet is the largest block of ice on Earth, covering more than 14 million square kilometers.
It has two main parts: the East Antarctic Ice Sheet, which is larger and more stable, and the West Antarctic Ice Sheet, which is smaller and more vulnerable to melting.
The ice sheet plays a crucial role in regulating the global climate, reflecting sunlight back to space and storing a huge amount of carbon dioxide.
It also affects the sea level, which would rise by about 60 meters if the ice sheet melted completely.
However, the ice sheet is not static. It is constantly changing, growing and shrinking in response to natural and human-induced factors.
For example, changes in the ocean temperature, the atmospheric circulation, the snowfall and the volcanic activity can all influence the ice sheet.
One of the biggest challenges for scientists is to determine the tipping points of the ice sheet, or the thresholds beyond which the ice sheet will undergo irreversible and rapid changes.
These tipping points could have dramatic consequences for the global climate and the sea level.
Among the factors that can trigger a tipping point is the landscape beneath the ice sheet. The shape and the slope of the bedrock can affect how the ice flows and how fast it melts.
For example, if the bedrock is smooth and sloping downwards, the ice can slide more easily and become unstable.
Professor Jamieson suggested that the landscape of Highland A could have implications for the stability of the East Antarctic Ice Sheet, which is currently gaining mass due to increased snowfall.
He warned that the valleys in the region could act as pathways for warm ocean water to reach the base of the ice and cause melting.
Jamieson said that the rate of ice retreat could depend on the thickness and the speed of the ice in the valleys, which could be affected by the shape of the landscape.
He added that the volcanic activity in the region could also have an impact on the ice sheet, by providing heat and creating subglacial lakes and rivers. These could lubricate the ice and make it flow faster
A window to the past and the future
The study of Highland A is part of a larger project called ICECAP, which aims to map the entire Antarctic continent using planes and satellites.
The project involves researchers from Australia, the UK, the US, France and China.
Professor Jamieson said that the project is important for improving our knowledge of Antarctica and its role in the global climate system. He said that by looking at the past, we can learn about the future.
Furthermore, he said that the landscape beneath the ice sheet tells us about the history of Antarctica, how it formed, how it evolved, and how it responded to past climate changes.
This can help us to model and predict how the ice sheet will behave in the future, and what the consequences will be for the sea level and the climate.
It also has a scientific and cultural value, as it reveals a hidden world that few people have ever seen.
The landscape under the ice is older than the ice sheet itself, and that it has been preserved for millions of years. He said that it is like a time capsule, a window to a different world.
