Every decade, 13% of the world melts irretrievably. sea ice in the northern hemisphere. In a few decades, it may disappear completely during the summer. Reducing its range in the northern hemisphere causes further climate changes and the occurrence of extreme weather phenomena on Earth, says an expert from the Polish Academy of Sciences.
The center of the Arctic is the Arctic Ocean, which is largely covered by drifting sea ice. This body of water is surrounded by the North American and Eurasian continents and archipelagos of islands. Since 1978, satellite observations and measurements have been carried out, which allow for accurate imaging and calculation of the Arctic sea ice coverage.
Every year, sea ice seasonally changes its extent, reaching its maximum area in the northern hemisphere at the end of winter, i.e. at the turn of February and March. The ice cover then has an average area of about 15 million square kilometers. The least ice is at the end of summer – in September. Then it occupies about 6 million square kilometers (this is the average for the years 1979-2019). For comparison, the area of the whole of Europe is about 10 million. sq km
How to stop the ice melting?
“In recent years, these values have decreased significantly and in the record year of 2012, in September, the sea ice cover covered only 3.34 million. sq km. In winter, in recent years, the area of sea ice exceeds just over 14 million. sq km – said a scientist from the Polar and Marine Research Department of the Institute of Geophysics of the Polish Academy of Sciences, Dr. Tomasz Wawrzyniak.
Stopping the process of melting sea ice in the Arctic can be difficult, because it is caused by rising temperatures on Earth, caused, among other things, by rising concentrations of greenhouse gases. According to Dr. Wawrzyniak, if people influenced the reduction of emissions – the global climate system should react.
However, if this trend is not stopped, the effects of the dramatic shrinkage of the Arctic sea ice cover will also be felt in Europe, the researcher warns.
“Sea ice in the Arctic is an indicator of global climate stability. Its disappearance has huge consequences for oceanic and atmospheric circulations. What is happening in the Arctic closely affects the occurrence of extreme phenomena, including droughts and floods, which are increasingly occurring on a global scale – he points out.
The lack of an ice cover causes warm Atlantic water to flow into the interior of the Arctic Ocean, which in turn causes an increase in air temperature. As a consequence, ocean circulation systems and sea currents change. Arctic air is no longer as cool, which changes the distribution of baric (atmospheric pressure) systems. In this way, for example, the influx of warm air masses from the south to Europe can be unblocked. Therefore, the disappearance of the ice, thousands of kilometers away from us, is felt by millions of people in lower latitudes.
Experts note that in a few decades, the ice in the Arctic may completely disappear. Publishing in Nature in August, British scientists analyzed the past of the Arctic (the period between the glaciations, about 127,000 years ago) and on this basis estimate that in a similar way the Arctic ice will most likely melt completely again by 2035.
“Currently, ice loss is 13 percent. per decade compared to the reference period. More open surface means more heat in the ocean and worse conditions for sea ice formation. Climate projections do indeed point to the disappearance of sea ice in the coming decades, although a few years ago, according to skeptics, this seemed impossible. The actual disappearance of sea ice is even faster than predicted until recently by climate models, which is why they are constantly being developed, confirms Dr. Wawrzyniak.
The scientist adds that the ice cover of the Arctic Ocean is largely no longer multi-year ice, which in some places was even more than 9 meters thick. Currently, it is thinner ice, growing cyclically in the winter, which melts easily in the summer. Every year it occupies less and less space and is thinner; in many areas it no longer forms at all.
The third lowest result since the beginning of the measurements
This year is also not favorable for the Arctic ice cover. In July, the lowest range was recorded for that month in the entire history of measurements. On August 20, the area of sea ice in the northern hemisphere was just over 5 million square kilometers.
– This result is the third lowest since the start of sea ice extent measurements. The area of sea ice was smaller in 2012 and 2019. A lot of ice-free spaces opened in August in the Beaufort and Chukchi Seas, after the storms that took place in July, the scientist adds.
Compared to the early 1980s, when the minimum ice cover in September was over 8 million sq km, it has now halved. – This is almost thirteen times the area of Poland (0.3127 million sq km). In the winter, this area decreased by 2 million square kilometers – emphasizes the climatologist.
Where do scientists get information about the Arctic ice sheet? Dr. Wawrzyniak says that they come from satellite or aerial observations, as well as from historical data dating back to the mid-nineteenth century, including sailing logs from ships sailing in the polar regions.
– We know from them that changes in the extent of sea ice began to be visible only at the end of the 20th century, as a result of the intensification of the greenhouse effect and the associated warming. The biggest changes have been observed since 2005, when the disappearance of sea ice has been more and more dramatic, he concludes.
You can read about sea ice in the Svalbard region (Norwegian province in the Arctic) and the correlation with air temperature in a publication co-authored by Dr. Tomasz Wawrzyniak.