Sea ice level is the area of ice that covers the Arctic Ocean at a provided time. A still image visualizing Arctic sea ice on September 16, 2021, when the ice appeared to reach its annual minimum level. NASA and the National Snow and Ice Data Center in Boulder, Colorado, use satellites to observe sea ice degree. Because sea ice forms from the seawater it floats on, it acts much like an ice cube in a glass of water. Like that ice cube, which does not change the water level of the glass when it melts, melting sea ice in the Arctic does not dramatically change sea level.
One method that researchers monitor climate modification is through the measure of sea ice extent. Sea ice level is the area of ice that covers the Arctic Ocean at a provided time. Sea ice plays an important role in reflecting sunshine back into area, managing ocean and air temperature, circulating ocean water, and preserving animal environments.
A still image envisioning Arctic sea ice on September 16, 2021, when the ice appeared to reach its yearly minimum level. On this date, the level of the ice was 4.72 million square kilometers (1.82 million square miles). Credit: NASAs Scientific Visualization Studio
NASA and the National Snow and Ice Data Center in Boulder, Colorado, utilize satellites to observe sea ice extent. Sea ice types in the cold winter season months, when seawater freezes into huge blocks of drifting ice, then partly melts away in the warm summertime months.
Here are 5 truths to assist you better comprehend Arctic sea ice.
1. Sea Ice Extent is Declining
NASA has actually tracked sea ice minimum (typically in September) and maximum (usually in March) degrees considering that 1978. While the specific extent figures might differ year to year, the general trend is clear: the Arctic is losing sea ice year-round.
In 2021, Arctic Sea Ice was 12th least expensive on record. Credit: NASA Earth Observatory images by Joshua Stevens, utilizing information from the National Snow and Ice Data Center
” The last 15 years, weve seen the most affordable 15 sea ice minimum degrees,” said Dr. Rachel Tilling, a sea ice researcher at the University of Maryland and NASAs Goddard Space Flight Center in Greenbelt, Maryland. “Each year were losing a location thats roughly the size of West Virginia.”
Arctic sea ice minimum degree is now decreasing at a rate of 13.1% per decade. The albedo effect describes the white ice surface areas capability to reflect Earth-bound sunshine back to area. When sea ice melts, darker-colored liquid water is left exposed to take in sunshine.
2. Sea Ice Helps Prevent Atmospheric Warming
Sea ice functions as a “blanket,” separating the ocean from the atmosphere, according to Tilling. In addition to keeping sunshine out, sea ice traps existing heat in the ocean, keeping it from warming the air above.
” The capability of the ice to keep heat in the ocean depends not only on its level, but likewise on its thickness,” Tilling stated.
With more ice melting every year, there is less recuring, multi-year ice. As a result, Arctic sea ice is as young and thin as it has actually ever been, making it a less efficient blanket.
Working from a mix of satellite records and declassified submarine sonar information, NASA researchers have actually built a 60-year record of Arctic sea ice density. Now, Arctic sea ice is the youngest and thinnest its been because we started keeping records. More than 70 percent of Arctic sea ice is now seasonal, which suggests it grows in the winter and melts in the summer, but doesnt last from year to year. This seasonal ice melts faster and breaks up easier, making it far more susceptible to wind and atmospheric conditions. Credit: NASA/Katy Mersmann
3. Sea Ice Affects Arctic Wildlife Above and Below Water
” Theres a huge ecosystem thats affected by modifications to sea ice,” Tilling said. As sea ice decreases, animals such as Arctic Foxes, polar bears and seals lose their environment.
There are results underneath the ices surface, too.
As ice crystals form atop seawater, they leave behind salt in the ocean listed below. This thick, salted water can sink to the bottom of the ocean. The descending water in one place will be offset by rising motion in others, which results in more nutrient-dense water distributing up toward the surface. Those nutrients are necessary to tiny phytoplankton, which are then eaten by fish and animals. The regular melt-freeze cycle keeps underwater Arctic life prospering, from algae to killer whales.
4. Sea Ice Melt Does Not Greatly Contribute to Sea Level Rise
Because sea ice kinds from the seawater it drifts on, it behaves much like an ice cube in a glass of water. Like that ice cube, which does not alter the water level of the glass when it melts, melting sea ice in the Arctic does not dramatically alter sea level.
NASAs Cloud, land and ice Elevation Satellite-2 (ICESat-2) will provide scientists with height measurements that produce a global portrait of Earths 3rd measurement, collecting data that can exactly track modifications of surface including glaciers, sea ice, and forests. Credit: NASA/Ryan Fitzgibbons
5. Satellites Allow NASA to Monitor Sea Ice
The Arctic Ocean is a challenging place to access and research study. Thats why NASA, the National Oceanic and Atmospheric Administration (NOAA), the European Space Agency, and others, rely on the vantage point of area to collect observations from the region. Two types of instruments are generally utilized to monitor sea ice, Tilling said.
The first type are passive microwave instruments, which track degree gradually. A series of these instruments aboard satellites supported by NASA, NOAA, the U.S. Department of Defense, and global partners, have actually kept an eye on arctic sea ice level considering that 1978– more than 40 years.
” Passive microwave instruments determine the microwave emission of surfaces,” Tilling stated. The microwave emissions happen naturally, and the signature of sea ice is different from that of water, permitting researchers to specifically locate both from year to year.
The 2nd type are altimetry instruments, which can be utilized to estimate sea ice thickness. NASAs Ice, land and cloud Elevation Satellite-2 (ICESat-2), released in 2018, uses a laser to determine the height of the ice and the height of the water. Using the recognized relationships between the two measurements (what height of ice above the waters surface represents the depth of the ice listed below it), researchers can determine its total density.
Researchers continue to study the Arctic to find out more about the regional and worldwide repercussions of lessening sea ice.
” Our world is this big, interconnected place, and the atmosphere is connected across it,” Tilling states. “The Arctic is altering so quickly, that we do not even know yet exactly how the modifications there are going to affect us. All we understand is that they will.”