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A study on Arctic ice indicates that the reduction in ice sheets was three times greater in summer 2018 than it was 40 years ago, melting at a rate of 12.8% every decade. This acceleration of the thaw is attributed to climatic phenomena such as El Niño that are perceived in tropical areas.
Arctic sea ice plays a key role in regulating the climate of the entire planet Earth and makes it possible to estimate and measure the impact of climate change. The ice pack layer (as sea ice is known) varies in extent throughout the year. In March it is at its maximum value and in September at the minimum.
Indian researchers have published a study in the journalHeliyon with details of the variations that occurred in summer 2018, comparing them with the previous data available since the first records, in 1979.
The conclusions indicate that for 40 years, this polar zone has lost sea ice in September at a rate of 12.8% per decade and 82,300 square kilometers per year. At the peak of ice loss, which this research dated in July 2018, the Arctic was losing 105,500 square kilometers of ice a day, an area larger than Iceland.
Avishnar Kumar, co-author of this work and senior researcher at the National Center for Polar and Ocean Research (NCPOR) comments that this reduction “may cause the Arctic to lose all its ice in the next three decades”.
The study authors estimate that this scenario would have an impact around the world, causing more aggressive climatic changes in latitudes well away from the Arctic Circle.
“Since we have satellite data available , it can be seen that about 50% of the September sea ice has broken off. Based on our knowledge of the loss of sea ice and on ongoing research, we can state that the rate of losses could increase due to rising temperatures”Kumar explains.
“The various parameters obtained offer an opportunity to measure and understand changes in sea ice through internal and external variables ”, the scientist points out. Data such as thickness and volume of ice sheets "Help to determine the processes of heat exchange between the ocean and the atmosphere, as well as the growth processes of sea ice”, He highlights.
The team was able to verify that the loss of sea ice in the summer of 2018 was three times greater than the data of 40 years ago. The work also points out that both the years where the extent of sea ice was minimal and the warmest September occurred in the last 12 years.
“Every year news appear warning of a new record in high temperatures or the fastest losses of sea ice in the Arctic. If the reduction continues at this rate, it can have catastrophic impacts on increasing air temperatures and slowing down global ocean currents.Kumar warns.
Furthermore, it states that “These planet-wide impacts are the reason you are interested in unraveling the mysteries of the polar regions”.
NCPOR research links this loss of sea ice to the warming of the world's oceans and its effect on the Arctic wind and atmospheric pressure cycles. Pay special attention to the El Niño phenomenon, a climatic event that changes the atmospheric and oceanic characteristics of the equatorial Pacific and causes extreme climatic processes in many parts of the world. This phenomenon occurs more and more frequently as the global average temperature increases.
Masses of air and hot water from the tropics
This cycle, the research notes, can move masses of air and warm water from the tropics to the Arctic, causing ice floes to melt and starting a loop known as "arctic amplification." The reduction in ice area gives way to darker marine waters that absorb more radiation from the sun. As they retain more heat, water temperatures rise and more ice melts, causing the Arctic region to warm at a faster rate - about four times more - than the rest of the world.
The researchers also wanted to draw attention to the Arctic atmosphere, from which they have been able to extract data to better understand this loss of sea ice. Thus, they highlight not only that September 2018 was the third warmest month in records, but that there was an important difference between the temperature over the Arctic Ocean (about 3.5º C) and the continental Arctic (about 2.8º C). This contrast, as Kumar explains, “can play a vital role in the amount of existing sea ice”.
The co-author notes that “if the ocean temperature rises, it will lead to a gradual loss of sea ice and fewer surfaces that reflect radiation”. Thus, a warmer ocean "will lead to delayed ice growth during fall and winter”And longer periods of exposure in summer, which is when the Arctic thawing and warming process begins.
The work proposes for future research to evaluate the reduction of sea ice and its influence on warm water intrusions in Arctic altitudes. "The world should look at tropical countries like India and try to understand a little more climate change and the polar regions."Kumar concludes.
Kumar et al .: "Global warming leading to alarming recession of the Arctic sea-ice cover: Insights from remote sensing observations and model reanalysis"Heliyon (July 2020).