Climate Variations in the Antarctic Region on a Long Time Scale and Current Climate Changes

Abstract

The Antarctic is a highly connected system with nonlinear interactions between the atmosphere, ocean, ice, and biota, as well as complex connections to the rest of the Earth system. Antarctica and the Southern Ocean make up the most important part of the Earth system. Antarctica is the coldest, driest, and most remote continent and is undergoing a variety of environmental changes in response to climate change, in particular modern warming, which is the subject of intense scientific debate. Almost all of Antarctica is located south of the Antarctic Circle (66°33′ S). The question remains as to whether the recent and accelerating warming trend is part of natural climate variability or the result of anthropogenic activities. We may not get an unambiguous answer if we do not decipher how climate processes changed in the distant past. Long-term trends (ups and downs) in continental ice deposits in the Antarctic region and in carbon dioxide content can be distinguished over the interval of approximately the last 500 Ma. Nearly 60–50 million years ago there was a long trend of decreasing carbon dioxide concentration, average temperature and lowering of the ocean level. Over the last million and hundreds of thousands of years, the history of the Earth has been characterized by alternating cycles of cold (glacial) and warm (interglacial) climatic fluctuations, which led to a number of large-scale environmental and atmospheric changes, in particular, the formation and melting of huge ice sheets, dramatic changes in global sea level, etc. This article examines long-term trends in climate change in various regions of Antarctica in the past, climate change since the end of the last ice age, and current climate change, and the relationship of these changes with the causes that give rise to them. The main attention is drawn to the changes in climatic characteristics during the Holocene and the features of changes in recent decades. The results we obtained are important for understanding past and future climate variability.