In addition to greenhouse gas emissions, deforestation, ocean acidification and, in particular, the disappearance of polar ice, are driving the rise in global temperatures. In a new study, scientists from the University of Arizona have proposed how to preserve the Arctic cap using geoengineering techniques.
The work, titled Arctic Ice Management, was published in the American Geophysical Union's Earths Future.
Scientists note that the current rate of shrinking Arctic ice is of serious concern. It is estimated that ice is disappearing at a rate of 3.5–4.1% per decade, and its total loss since the start of satellite measurements in 1979 is at least 15%. In 2016, sea ice levels were the second lowest on record, and worst of all, the process is gaining momentum.
The global average temperature has increased linearly with CO2 emissions and is projected to increase by 3 ° C or more by the end of the century. Nearly all scenarios predict year-round reductions in sea ice in the Arctic and a nearly ice-free Arctic Ocean by 2050.
One of the reasons the Arctic heats up faster than the rest of the planet is due to its high ice albedo. Fresh snow and ice reflect up to 90% of sunlight, while open water (which has an albedo of about 0.06) absorbs most of it. Consequently, the more ice melts, the more sunlight is absorbed and the temperature in the Arctic rises.
A research team led by Professor Stephen Dash of the School of Earth and Space Research studied how ice melting is associated with seasonal fluctuations.
New, or annual, ice that forms each winter is usually only 1 meter thick. If it can withstand the Arctic summer, it can grow into a perennial one with a typical thickness of 2–4 meters. But due to the current situation, when the summer is getting warmer, the first-year ice succumbs to the seasonal heat, and the layer breaks up without even starting to grow. If in the 1980s multi-year ice accounted for 50-60% of all ice in the Arctic Ocean, then by 2010 it was only 15%.
With this in mind, Dash and his colleagues came up with a way to help one-year-old ice get through the warm summer. In their opinion, during the Arctic winter, when water freezes better, it can be pumped to the surface using wind-powered pumps.
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Calculations of wind speed in the Arctic have shown that a wind turbine with 6-meter blades will generate enough electricity to lift water up to 7 meters with one pump at a speed of 27 metric tons per hour. As a result, the ice sheets will become thicker and will be able to withstand summer temperatures, then turning into stable multi-year ice.
Over time, the negative feedback created by the increased ice cover will result in less absorption of sunlight by the ocean and ice accumulation.
Although some details of the concept require improvement, it seems quite reasonable and takes into account both local seasonal changes and global ones. According to scientists, this idea can be implemented with a relatively modest budget of $ 500 billion per year for the entire Arctic, or $ 50 billion per year to "freeze" 10% of the territory.