(CN) — The Arctic lost about 6 million square miles of sea ice during the summer of 2018, three times the loss reported by meteorological satellites four decades ago, according to a study by climate experts with India’s Ministry of Earth Sciences.
Thanks to improvements to temporal sensing technology and greater coverage by satellites, the scientists were able to monitor and measure the thickness, concentration and volume of sea ice in the Arctic during 2018’s boreal summer — the period between July and September when the northmost regions of Earth experience their warmest temperatures before the long winter begins anew.
Avinash Kumar, a senior scientist at India’s National Centre for Polar and Ocean Research, led his colleagues Rahul Mohan and Juhi Yadav in calculating the loss of Arctic sea ice. The trio found that the Arctic was losing 105,500 square kilometers, or about 65,500 square miles — an area larger than Kentucky — of sea ice daily during July 2018.
By the end of September, the ice had been reduced to just one-third of its winter level.
“The loss of sea ice extent and sea-ice concentration was attributed to the impacts of land-ocean warming and the northward heat advection into the Arctic Ocean,” Kumar wrote in an email interview with Courthouse News. “This has resulted in considerable thinning of sea-ice thickness and reduction in the multiyear ice for summer 2018.”
The group’s findings fit into a trend of rapidly shrinking sea-ice extension in the Arctic.
“Our study shows that both the minimum sea-ice extent and the warmest September records occurred in the last 12 years,” Kumar said in a statement. “If the decline of sea ice continues to accelerate at a rate of 13% per decade in September, the Arctic is likely to be free of ice within the next three decades.”
Sea ice coverage reflects radiation from the Sun, so as less of the Arctic region is covered by ice, the exposed seas begin to retain more of the Sun’s heat over time.
“The Arctic has been warming since the year 2000, and the main reason now is that the Arctic has a less reflective surface and more open areas. Thus, this open sea allows more heat to be absorbed, which initiates the process of melting sea ice and further amplifies the warming,” Kumar wrote. “So, more absorption of heat results in rising temperature. Thus, warmer ocean water will lead to delay in growth of ice during autumn and winter as well as expose the region for longer duration in summer and here begins the cycle of warming and melting.”
Sea ice coverage makes a noticeable difference. Just as sea ice loss results from warming trends elsewhere in the globe, its effects are far-reaching and complex as well.
“If the decline in sea ice continues at this rate, the roots of the various catastrophic climatic conditions could soon be strengthened. In recent times, one such impact [is] that the Arctic air temperature is rising,” Kumar wrote.
The scientists note in their research — published Wednesday in the open-access scientific journal Heliyon and funded by the Indian government — that air above the Arctic Ocean measured at about 3.5 degrees Celsius, significantly warmer than the air above Arctic land, which measured about 2.8 degree Celsius.
“Additionally, the ocean is an important component of the climate system that helps to redistribute global heat from the tropics to the poles and also helps to maintain a heat exchange balance with the atmosphere,” Kumar wrote. “Hence, sea ice decline in the Arctic leads to extreme weather conditions in the tropics.”
El Niños, for instance, have occurred more frequently as the Earth has warmed. These cycles form positive feedback loops when they begin drawing warm tropical air and water to the Arctic, resulting in greater sea-ice melt.
As a result, the Arctic has heated up about four times faster than the rest of the world — just outpacing the South Pole’s own rapid warming.
“The changes taking place in the Arctic can lead to other changes in lower latitudes, such as extreme weather conditions,” Kumar said in the statement. “The world should be watching tropical countries like India, with our research center saddled close to the beaches of Goa, and trying to understand — even in a small way — more about climate change and the polar regions.”