Are There Trees on Antarctica and Were There Ever?

Antarctica, known for its vast icy expanses, currently hosts no trees or shrubs. Its environment is among the most extreme on Earth, characterized by low temperatures, strong winds, and minimal precipitation. With 99.5% of its surface perpetually covered by ice, it is the coldest, driest, and highest continent. These harsh conditions severely restrict plant life.

Antarctica’s Current Plant Life

Despite its challenging environment, Antarctica supports a unique array of plant life, primarily in ice-free coastal areas and the Antarctic Peninsula. The flora consists of simpler forms: 100 species of mosses, 25-30 species of liverworts, and around 250 species of lichens. These non-vascular plants lack true roots, absorbing water and nutrients directly. They persist in damp, sheltered locations, forming small green oases and surviving freezing by reducing metabolic activity.

Only two native flowering plants, Antarctic hair grass (Deschampsia antarctica) and Antarctic pearlwort (Colobanthus quitensis), are found on the continent. These vascular plants are restricted to the northern and western Antarctic Peninsula and nearby islands, where conditions are milder with more precipitation. Antarctic hair grass grows in dense tufts with deep roots, anchoring it against winds and aiding nutrient absorption, and can withstand trampling. Antarctic pearlwort forms small, cushion-like growths in rocky coastal areas.

Both species exhibit adaptations like self-pollination and wind-pollination, as insects are absent. Their compact forms conserve heat and moisture, allowing photosynthesis even at freezing temperatures. Pearlwort can withstand temperatures as low as -20°C, utilizing ‘antifreeze’ proteins and special cells.

A Forested Past

In stark contrast to its present-day icy landscape, Antarctica was once home to lush forests millions of years ago. Geological evidence, including fossilized leaves, wood, pollen, and amber, confirms temperate rainforests thrived across the continent. Fossil fragments dating back 280 million years indicate forests grew before dinosaurs appeared during the Permian period. Some fossil logs up to seven meters high have been found standing upright on Alexander Island, with preserved root systems attached to carbonaceous soil.

These ancient forests included Nothofagus (southern beech) and various conifers. During the Cretaceous period, about 90 million years ago, coniferous forests dominated West Antarctica, with southern beech becoming more prominent later. Evidence from sediment cores suggests temperate lowland rainforests extended close to the South Pole, with average temperatures around 12 to 19 degrees Celsius. This indicates a warmer, frost-free environment with ample moisture.

During the Triassic period, the continent was home to seed ferns (genus Dicroidium), ginkgophytes, cycadophytes, and other conifers. Around 280 million years ago, polar forests existed whose trees could transition rapidly from summer activity to dormancy within about a month. This allowed them to cope with polar light cycles, a mechanism not seen in modern plants.

The Vanishing Forests

Antarctica’s transformation from a forested land to an ice-covered continent was a gradual process driven by geological and climatic shifts over millions of years. A primary factor was continental drift; Antarctica separated from Gondwana and moved towards its present position over the South Pole. This movement began around 160 million years ago, with significant separation from South America and Tasmania occurring 30 to 35 million years ago.

The opening of the Drake Passage between Antarctica and South America, and the widening of the sea between Antarctica and Australia, allowed the formation of the Antarctic Circumpolar Current. This powerful ocean current created thermal isolation, preventing warmer waters from reaching its coasts and leading to substantial cooling. Concurrently, global cooling trends, particularly a decrease in atmospheric carbon dioxide levels after about 55 million years ago, contributed to the planet’s transition from a “greenhouse” to an “icehouse” climate.

These combined factors gradually made the environment unsuitable for the once-thriving forests. Permanent glaciation began around 34 million years ago, initially in East Antarctica. Snow accumulated on mountaintops, compressing into glacier ice over time. This ice spread across the continent, creating the massive ice sheets seen today.

Increasing ice cover further reinforced cooling through a feedback mechanism: more ice reflected sunlight, lowering surface temperatures. This long-term cooling and extensive ice sheet formation led to the complete disappearance of Antarctica’s forests, leaving behind the treeless, frozen landscape.