Will humanity soon witness the complete disappearance of the Arctic Polar Ice Cap?
The Arctic sea ice, a vast surface of frozen seawater floating on the Arctic Ocean and on the neighboring seas, has been declining in the past decades.
Unfortunately, as its extent reduced, the oldest and thickest ice has melted and thus, the sea ice cap became more vulnerable to the atmosphere and the warming ocean, writes Maria-Jose Vinas from NASA’s Earth Science News Team.
According to the sea ice researcher from NASA, Walt Meier, this ice serves as a defensive wall for the sea ice. Namely, a warm summer can melt the young and thin ice; however, it can’t entirely remove the older ice.
However, the older ice is weakening due to its declination and consequently, it’s easier to be broken up and thinned out.
Is the Ice Cap Really Disappearing?
The direct measures of the ice’s thickness are incomplete across the Arctic; so scientists have made estimates of ice age and followed the evolution from the year of 1984 to 2016.
The time lapse video published by NASA shows how the sea ice has been shrinking, spinning, and drifting out of the Arctic in the last thirty years.
Meier explains that ice age is an excellent analog for the ice’s thickness due to the fact that as ice becomes older, it becomes thicker. He adds that this is a result of the ice growing more in winter than melting in summer.
Back in the 2000s, University of Colorado scientific team found a way to keep track of the ice movement on the Arctic and age evolution through the usage of several types of data, but mostly data from satellite microwave instruments.
What Kind of Tech Was Used for the Monitoring?
These instruments measure the brightness temperature or the energy emitted by the ice which is impacted by the temperature of the ice and its salinity, surface texture, and snow layer on top of the ice too.
Each ice flow has a specific brightness temperature; therefore, the team needed to create a method that can identify and track these floes in passive images as they moved through the Arctic.
The system also used info from weather data and drifting buyos. Meier, who also collaborates with the Colorado scientists explains that this is a way to keep track of the sea ice, until it melts or leaves the Arctic, unfortunately.
The Moving Arctic Ice
Annually, sea ice is formed in the winter period and it melts down in summer. The ice that remains after the melting thickens as the time goes by and it can grow up around 3 to 7 feet of thickness in the first year. Ice that has survived melting from several years may reach around 10 to 13 feet of thickness.
This ice is less prone to melting and the risk of being pushed by winds or dissolved by waves and storms is lower.
But, the Arctic sea ice has been decreasing in surface in the last years and becoming thinner. In the video, where the ice is almost gelatinous in texture, it has undergone major changes during the period of measurements, Meier emphasizes.
Nonetheless, the ice isn’t moving constantly, but this is the overall pattern. When the spring melting begins, the ice begins to shrink and disappears. The video also shows the two main areas of lost thick ice.
The first one began in 1989 and lasted for couple of years and happened because of a switch in the Arctic atmospheric circulation pattern and the second one began in the mid 2000s.
Meier notes that unlike in the 80s, it’s not that much ice disappearing; however, a lot of it is being lost. Namely, thick ice in the 80s was around 20 percent of the ice cover of the sea and now, it’s only 3 percent!
Scientists note that this older ice was insurance for the sea ice pack in the Arctic and as we’re losing it, the chances for an ice-free summer there become higher.