Deglaciation
As a result of all of this, the world's main ice sheets, including the ones located in Eurasia, North America and parts of the Antarctic melted.
The repeated periods of increased and decreased extent of the global cryosphere (as deduced from observations of ice and rock cores, surface landforms, sub-surface geologic structures, the fossil record, and other methods of dating) reflect the cyclical nature of global and regional glaciology measured by ice ages and smaller periods known as glacials and interglacials.
Human activities promoting climate change, notably the extensive use of fossil fuels over the last 150 years and the resulting increase in atmospheric CO2 concentrations, are the principal cause of the more rapid retreat of alpine glaciers and continental ice sheets all across the world.
[9] For example, the West Antarctic Ice Sheet has receded significantly, and is now contributing to a positive feedback loop that threatens further deglaciation or collapse.
Newly exposed areas of the Southern Ocean contain long-sequestered stores of CO2 which are now being emitted into the atmosphere and are continuing to impact glacial dynamics.
If on a large enough scale, an increase in volcanic activity provides a positive feedback to the process of deglaciation as a result CO2 and methane released from volcanos.
[18] For example, interruptions of the usual deep cold water circulation and penetration depths in the North Atlantic have feedbacks that promote further glacial retreat.
The recent period of intense deglaciation has resulted in an average global sea level rise of 1.7 mm/year for the entire 20th century, and 3.2 mm/year over the past two decades, a very rapid increase.
[20] The physical mechanisms by which deglaciation occurs include melting, evaporation, sublimation, calving, and aeolian processes such as wind scouring.
Throughout the Pleistocene Epoch, the Laurentide Ice Sheet spread over large areas of northern North America, with over 5,000,000 square miles of coverage.
19k-11k years ago), shows changes in greenhouse gas concentrations and of the Atlantic meridional overturning circulation (AMOC), when sea-level rose by 80 meters.
Not only were ice sheets and greenhouse gases experiencing alteration, but also additionally to this, there was sudden climate change, and many occurrences of fast, and sizeable rising of sea level.
Nonetheless, the globe had arrived at its present interglacial period, where climate is comparatively constant and stable, and greenhouse gas concentrations exhibit near pre-industrial levels.
This data is all available due to studies and information gathered from proxy records, both from the terrestrial and ocean, which illustrates overall global patterns of changes in climate whilst in the period of Deglaciation.
Studying exposed landforms can also inform the understanding of the present and near future as glaciers all over the world retreat in the current period of climate change.
