Glaciation makes land vulnerable to repeated offensive ice

Glaciation of some of the land and the appearance of characteristic glacial landforms makes them highly vulnerable to re-attack the ice, which can serve as a reason for even small climate change, climate scientists say in a paper published in the journal Nature.

It is believed that during its existence, Earth has experienced several ice ages, as in the past, at the dawn of life, and more recently — 2.5 million years ago. These events were accompanied by a significant expansion of the polar ice caps and lower average temperatures. Traces of the last glaciation preserved as fjords, hills, drumlins, eskers arched, rock-'mutton foreheads "and many other glacial landforms.

Vivi Pedersen (Vivi Pedersen) from the University of Bergen (Norway) and her colleague David Egholm (David Egholm) from the University of Aarhus (Denmark), tried to find out how changes in the landscape after the land and the disappearance of glaciers affect how it responds to changes in climate .

For this Egholm Pedersen and studied climate in modern glacial landscapes of northern Europe and North America, as well as surrounding areas, which were not affected by glaciation.

They used this data to create a special climate model to follow changes of glaciers with increasing or decreasing temperature. In this model, the researchers took into account all the possible factors affecting the "health" of the glacier — precipitation, degree of light, depth, ice, and other parameters.

Scientists have conducted several simulation sessions, changing the degree of erosion of the relief and other simulation parameters, trying to find the differences in the response to climate change.

It turned out that the glacial landforms significantly affect the stability of the climate and appearance of land. In general, the appearance of moraines, drumlins, and other "traces" of the glacier made the area more vulnerable to re-freezing. Thus, even a small decrease in temperature was enough to return the ice, which did not occur in landscapes devoid of glacial landforms.

As the climate scientists, this phenomenon may explain rapid climate change in the middle of the last glacial period, 950,000 years ago. According to them, the gradual saturation of the relief of the northern parts of Eurasia and North America, "traces" of the glacier led to a lengthening of the micro-glacial periods, and reduce periods of relatively warm climate.

Such a result model coincides with the data obtained in the study of sedimentary rocks that talk about going from 40 thousand year cycles of relatively cold and warm climate to the 100 thousand-year glacial cycles.

Believed Egholm Pedersen and their simplified model and its analogues can be integrated into larger climate models to better reflect how changes in temperature affect the state of the glaciers in the land. This will help professionals better predict the effects that cause climate change in the polar regions of the Northern Hemisphere in the coming years.

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