Climate Change and the Antarctic continent
Antarctica and climate change
Most of Antarctica is a vast plateau, the coldest, windiest and driest place on Earth.
Antarctica is an ice-covered land mass surrounded by the ocean. It is unlike the Arctic, which is an ice covered ocean surrounded by land. In size it is bigger than Europe, and is the coldest, driest, highest and windiest continent with a record low temperature of -94°C.
When it comes to climate change, the Arctic sea ice melting is succeeded in importance only by climate change in Antarctica. As it melts and breaks away from the land, it raises sea levels worldwide. Going by a 2017 climate change study, if GHG (greenhouse-gas emissions) keep rising at the current rate, the sea-level would increase by four feet before the end of the century. Another Antarctica and climate change study has found that more snowfall on the eastern peninsula – caused by climate change – could offset that somewhat, but the snow is likely only to slow sea-level rise, not stop it.
Global warming and climate change in Antarctica
Antarctica’s western peninsula has now warmed so much that only native flowering plants, hair grass and (yellow-flowered) pearlwort, are spreading alongwith invasive grasses and lichens. Also, green moss is spreading three times as fast. Island peaks once cloaked in snow have melted and expose mud or yawning crevasses.
Ice loss exposes warm water to cold air, increasing evaporation, which returns later as snow -and at times even as rain.
The warmer water pulled up from the deeper parts affects ice on land, by eroding glaciers where they meet the sea as floating shelves. Some 596 of western peninsula’s 674 glaciers are retreating as per a British survey. In other parts of Antarctica, much larger ice shelves are melting, bringing about a rapid rise in world sea levels. The same situation exists on the eastern peninsula.
There are two main causes of mean sea level rise globally – water added by the melting ice sheets and glaciers, and the expansion of sea water as it warms. The melting of Antarctica’s ice sheet is presently responsible for 20 – 25 % of global sea level rise globally.
We’re only 4,000 days away from 450ppm at which we risk warming of 2°C which will mean total climate chaos.
Why climate change in Antarctica needs to be tackled urgently
One of the Earth’s time epoch was the Pliocene, 2.6 – 5.3 million years ago. Then, Earth’s temperatures were warmer than now, possibly by 2 – 3 degrees. These conditions allowed plant growth even in the centre of Antarctica (as evidenced by the fossil remains of plants discovered in the Antarctica). The sea levels too were higher, probably by 10 -20 metres above today’s ocean surface.
What’s noteworthy is that the carbon dioxide quantity in the atmosphere was very similar to what it is today – in excess of 400 CO2 ppm (parts per million). The last time in Earth’s history that the atmosphere carried the same amount of the CO2 was in the Pliocene epoch. Temperatures may presently currently be lower than those observed during the Pliocene, but that’s understandable because there is a time lag. It takes time for the temperature to get to those levels just as in an oven.
The Pliocene is an apt example of where climate change in Antarctica could take us if carbon emissions go unchecked. Unless CO2 levels are brought down to 40% of what they are today – by 2030 and 0 by 2050, and with no emissions after that.
This is possible but it requires tremendous will and massive discipline on part of all the nations, especially the polluting ones in reversing climate change on Earth.
Concudingly, the single most important data point in the world today (on June 7) was 414.41 parts per million CO2 in atmosphere. This a year back was 409 ppm and 50 years ago was 326.66 ppm.
(Image: © Yann Arthus-Bertrand/Getty Images Plus) An ancient rocky structure found at the heart of the Ross ice shelf helps determine where Antarctica’s ice melts and where it stays firm and frozen. The structure is an old tectonic boundary, probably formed during the birth of the Antarctic continent or shortly thereafter.
By the end of austral winter, the seas around Antarctica are blanketed with as much as 18 million square kilometers of ice-an area about twice the size of the continental United States. But that vast span of ice is not always continuous. Cracks can open up and expose the seawater below.
The ROSETTA-Ice project, a three-year, multi-institutional data collection survey of Antarctic ice, has assembled an unprecedented view of the Ross Ice Shelf, its structure and how it has been changing over time. In a study published today in Nature Geoscience, the ROSETTA-Ice team members detail how they discovered an ancient geologic structure that restricts where ocean water flows.
Almost a quarter of the West Antarctic ice sheet is now affected by ice thinning, according to a new study.
A study has found a range of future outcomes that go from bad to worse when it comes to the uncertainities around sea level rise.
(Image: © Andrew Shepherd) Glaciers and ice sheets in Antarctica have thinned and weakened dramatically over the past quarter-century, leaving 24% of the ice in the western part of the continent seriously weakened and in danger of collapse. In some places on Antarctica, glaciers have thinned by approximately 400 feet (122 meters).
Ice losses are rapidly spreading deep into the interior of the Antarctic, new analysis of satellite data shows. The warming of the Southern Ocean is resulting in glaciers sliding into the sea increasingly rapidly, with ice now being lost five times faster than in the 1990s.
Today’s Image of the Day is an excerpt from our feature story: The Wide View of a Shrinking Glacier-Retreat at Pine Island. Pine Island Glacier is one of many outlet glaciers around the perimeter of Antarctica, but observations have shown that this glacier is worth extra attention.
The fetid waste of penguins and elephant seals helps spread nutrients across surprisingly large areas of Antarctica. This fertilizer traveled nearly as far as a kilometer (0.6 miles) past the edges of their active outposts, floating on the chilled Antarctic winds.