Ice age 2.7 million years revealed the features of the Earth’s climate in the distant past



    A few days ago a group of scientists spoke about an interesting discovery: in Antarctica, it was possible to obtain an ice sample whose age, according to glaciologists, reaches 2.7 million years. This is as much as 1.7 million years more than the previous record. The value of this ice is that it is a preserved sample of water and gases, from which you can understand what climatic conditions were on the Earth in its past. Gas bubbles frozen in ice help scientists determine the composition of the atmosphere that existed on the planet millions of years ago. Just then, about three million years ago, something happened that contributed to the onset of ice and a general cooling of the climate.

    The value of this sample is simply unbelievable, says David Schuster, a geochemist at the University of California, Berkeley. “This is the only example of the ancient atmosphere of the Earth that we now have,” the scientist said. This is true, plus obtaining an ice sample of this age is fraught with a number of purely technological difficulties: the well must be very deep, and drilling has to be done under extreme conditions. Plus, ancient ice is quite difficult to find, a thorough analysis of glaciers in different regions of the Antarctic is required.

    Experts have already managed to analyze the air from bubbles frozen in ice. As it turned out, the carbon dioxide content of 2.7 million years ago was about 300 parts per million, which is significantly lowercurrent indicator. According to a number of climatologists, it is precisely the relatively low content of carbon dioxide in the Earth’s atmosphere that contributed to the onset of cooling. Previously, the composition of the atmosphere was determined by the fossil remains of animals and plants. But this is a very inaccurate analysis, which, by the way, showed a higher content of carbon dioxide in the atmosphere than was determined now.

    It is clear that the results obtained need to be double-checked. But if they are fair, then scientists will have to rebuild some parameters of paleoclimatic models. The fact that scientists discovered such an ancient sample of ice suggests that similar discoveries are possible in the future, maybe scientists will be able to find even older samples. As a result, specialists will be able to build more accurate paleoclimatic models than those that currently exist. In addition, in some cases, climatologists and their colleagues find it difficult to say what was the composition of the atmosphere millions of years ago.

    Scientists prefer to take ice samples in Greenland and Antarctica. To obtain truly ancient samples, it is usually necessary to drill in regions where ice has accumulated over a long period of time. In this case, climate change can be monitored by layers, as the conditions in which this tree was grown are monitored by annual tree rings. Only years cannot be traced here, but millennia without problems. In the case of ice, scientists also analyze the gases included in the ice and the ice itself, more precisely, water. At the moment, the oldest sample was considered to be ice raised from the bottom of a well in Antarctica in 2004.

    Ancient ice was discovered in East Antarctica, 200 km from McMurdo Station. This is the largest settlement, port, transport hub and research center in Antarctica. It belongs to the US Antarctic Program, but also serves stations and research programs of other states. This region has deposits of so-called blue (or blue) ice , which accounts for only 1% of the total ice volume in the Antarctic. It is formed as a result of compression of precipitated snow, which becomes part of the ice on which it is located. When compressed, gas bubbles remain in the ice, ice crystals increase, which gives the ice a blue or even blue color.

    Soon, scientists will make a new attempt to break into the past of the Earth with the help of frozen water. This time they hope to get an ice sample of 5 million years old when the concentration of carbon dioxide is believed to be above 300 ppm. According to some experts, ice in the Antarctic began to form about 30 million years ago (in some regions). Probably, such ancient samples cannot be found, since ice is unlikely to have remained unchanged for all these tens of millions of years. But ice, 3-5 million years old, can probably be found.

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