Question

How the weather pattern has changed due to the climate change

Answer 1

The Antarctic environment is showing clear signs of climate change, which is likely to have profound effects on Antarctic species and ecosystems.

The East Antarctic Ice Sheet is losing ice at its coastal fringes—about 60 billion tonnes each year since 2006. The loss is occurring at an increasing rate and may contribute significantly to sea level rise. The upper layers of the Southern Ocean have warmed by 0.2°C since the 1950s. This rate of warming is faster than elsewhere in the world.

The ozone hole has largely protected East Antarctica from global warming.

Over the past half–century, western Antarctic surface temperatures have shown general warming trends with significant regional patterns. The Antarctic Peninsula is warming faster than anywhere else on Earth. In East Antarctica, the lower stratosphere has cooled and changed the atmospheric circulation through the loss of stratospheric ozone. A recovery of the ozone hole will reverse these processes and significantly increase the warming trend in East Antarctica.

The terrestrial ecosystems are changing, especially where snow fall is replaced by rain.

Retreating glaciers (particularly in the subantarctic), higher ambient temperatures and precipitation as rain rather than snow make the terrestrial environment more accessible to plant and microbial communities. A warmer climate and increased availability of liquid water enables their populations to expand and nonnative species to become established.

Antarctic vertebrates are highly specialised to survive in the Antarctic. Whether they can adapt to new conditions due to climate change is currently unknown.

Environmental changes cascade through ecosystems. In the Antarctic Peninsula region, an apparent decrease in the abundance of Antarctic krill has been attributed to the reduction in winter sea ice coverage. This in turn has caused a decrease in Adélie and chinstrap penguin populations. As the rate of environmental change increases, it may exceed the rate at which Antarctic vertebrates can adapt. Warmer waters also enable alien species to extend their range southward. Invading species are likely to outcompete, and perhaps replace, native species. It is likely that some native species will not survive the coming decades.

Increased acidification of the Southern Ocean can affect the base of Antarctic food webs.

Dissolved carbon dioxide acidifies the ocean and reduces the availability of carbonate ions that calcium carbonate shell-making organisms require for calcification, diminishing the ability of these organisms to form shells. Increasing ocean acidity due to increased levels of carbon dioxide is already affecting calcifying organisms—the shells of planktonic organisms known as foraminifera, which are food for many other organisms, are now about one-third lighter compared with pre–industrial times. These types of changes, which affect the base of the food web, can potentially change the dynamics of the Southern Ocean ecosystem significantly.

The pressure of human activities on Antarctica and the Southern Ocean is increasing.

The Protocol on Environmental Protection to the Antarctic Treaty commits signatories to comprehensive protection of the Antarctic environment. Australia has ratified the protocol by establishing legislation to enforce procedures that reduce the impacts of Australians visiting Antarctica and has taken practical steps to reduce the impacts of past activities, such as the clean–up of abandoned waste disposal sites. However, the human footprint in the region is gradually increasing. New stations are still being built; tourism to the continent continues to grow, particularly to the Antarctic Peninsula near South America; and, with a growing world population, commercial fishing activities are likely to increase.