Scientists with the European Space Agency (ESA) said on May 25, 2021, that satellite data have revealed how much warming Atlantic waters are intruding on Arctic sea ice. They said they made their announcement “with alarm bells ringing about the rapid demise of sea ice in the Arctic.” Previous research had suggested that sea ice can recover during the Arctic winter, following a strong summer melt. The idea was that thin ice grows faster than thick ice. However, new findings show that heat from the Atlantic Ocean is overpowering this stabilizing effect. It’s reducing the volume of sea ice that can regrow in the winter, leaving Arctic sea ice even more vulnerable during warmer summers and winter storms.
Sea ice scientists are calling this process Atlantification.
The new research was published May 18, 2021 in the Journal of Climate. It describes how scientists used satellite data from ESA’s Climate Change Initiative to calculate changes in the volume of Arctic sea ice between 2002 and 2019. The data came primarily from ESA’s CryoSat and SMOS satellites. Sea-ice physicist Robert Ricker of the Alfred Wegener Institute in Germany led the study. He said:
Over the last decades we observed the tendency that the less ice you have at the beginning of the freezing season, the more it grows in the winter season.
However, what we’ve found now is that in the Barents Sea and Kara Sea regions, this stabilizing effect is being overpowered by ocean heat and warmer temperatures that are reducing the ice growth in winter.
Arctic sea ice grows and shrinks
The Arctic isn’t a continent, as is the Antarctic. It’s an ocean. Sea ice floating in the Arctic grows and shrinks with the seasons. It reaches a maximum around March after the cold winter months, and then it shrinks to a minimum around September. Although some of the older, thicker ice remains throughout the year, these scientists said, there is an “undeniable trend” of declining ice:
… As climate change tightens its grip on this fragile polar region.
We think of seasonal swings happening as Earth’s air temperatures rise and fall. But warming air isn’t the only thing that can melt sea ice. The temperature of adjacent ocean water also adds to Arctic sea ice’s vulnerability.
Ricker and his colleagues mapped regional changes in sea-ice volume owing to drift. They calculated how much ice grows because of freezing each month. And they also used model simulations to explore the causes of change, which corroborated their findings. Ricker commented:
Over the last decades we observed the tendency that the less ice you have at the beginning of the freezing season, the more it grows in the winter season.
However, what we’ve found now is that in the Barents Sea and Kara Sea regions, this stabilizing effect is being overpowered by ocean heat and warmer temperatures that are reducing the ice growth in winter.
Importantly, this also means that if you have a warm summer or strong winds, the sea ice is less resilient
The rexearchers said they believe that the stabilizing mechanism in other regions of the Arctic could also be overpowered in the future.
Bottom line: Warm water from the Atlantic Ocean is making it harder for Arctic sea ice to form over winter.
Source: Evidence for an Increasing Role of Ocean Heat in Arctic Winter Sea Ice Growth
The post Arctic sea ice succumbs to Atlantification first appeared on EarthSky.
from EarthSky https://ift.tt/3wNiCr1
Scientists with the European Space Agency (ESA) said on May 25, 2021, that satellite data have revealed how much warming Atlantic waters are intruding on Arctic sea ice. They said they made their announcement “with alarm bells ringing about the rapid demise of sea ice in the Arctic.” Previous research had suggested that sea ice can recover during the Arctic winter, following a strong summer melt. The idea was that thin ice grows faster than thick ice. However, new findings show that heat from the Atlantic Ocean is overpowering this stabilizing effect. It’s reducing the volume of sea ice that can regrow in the winter, leaving Arctic sea ice even more vulnerable during warmer summers and winter storms.
Sea ice scientists are calling this process Atlantification.
The new research was published May 18, 2021 in the Journal of Climate. It describes how scientists used satellite data from ESA’s Climate Change Initiative to calculate changes in the volume of Arctic sea ice between 2002 and 2019. The data came primarily from ESA’s CryoSat and SMOS satellites. Sea-ice physicist Robert Ricker of the Alfred Wegener Institute in Germany led the study. He said:
Over the last decades we observed the tendency that the less ice you have at the beginning of the freezing season, the more it grows in the winter season.
However, what we’ve found now is that in the Barents Sea and Kara Sea regions, this stabilizing effect is being overpowered by ocean heat and warmer temperatures that are reducing the ice growth in winter.
Arctic sea ice grows and shrinks
The Arctic isn’t a continent, as is the Antarctic. It’s an ocean. Sea ice floating in the Arctic grows and shrinks with the seasons. It reaches a maximum around March after the cold winter months, and then it shrinks to a minimum around September. Although some of the older, thicker ice remains throughout the year, these scientists said, there is an “undeniable trend” of declining ice:
… As climate change tightens its grip on this fragile polar region.
We think of seasonal swings happening as Earth’s air temperatures rise and fall. But warming air isn’t the only thing that can melt sea ice. The temperature of adjacent ocean water also adds to Arctic sea ice’s vulnerability.
Ricker and his colleagues mapped regional changes in sea-ice volume owing to drift. They calculated how much ice grows because of freezing each month. And they also used model simulations to explore the causes of change, which corroborated their findings. Ricker commented:
Over the last decades we observed the tendency that the less ice you have at the beginning of the freezing season, the more it grows in the winter season.
However, what we’ve found now is that in the Barents Sea and Kara Sea regions, this stabilizing effect is being overpowered by ocean heat and warmer temperatures that are reducing the ice growth in winter.
Importantly, this also means that if you have a warm summer or strong winds, the sea ice is less resilient
The rexearchers said they believe that the stabilizing mechanism in other regions of the Arctic could also be overpowered in the future.
Bottom line: Warm water from the Atlantic Ocean is making it harder for Arctic sea ice to form over winter.
Source: Evidence for an Increasing Role of Ocean Heat in Arctic Winter Sea Ice Growth
The post Arctic sea ice succumbs to Atlantification first appeared on EarthSky.
from EarthSky https://ift.tt/3wNiCr1
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