Please help keep this Site Going

Menopausal Mother Nature

News about Climate Change and our Planet

Uncategorized

Arctic sea ice succumbs to Atlantification

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.

Two people in bright orange jumpsuit, standing on a field of Arctic sea ice.
The MOSAIC expedition to the Arctic – largest polar expedition in history – tweeted this image in 2020. It’s sea-ice physicists Robert Ricker and Stefanie Arndt, walking on an Arctic ice floe. Image via Twitter.

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.

Side-by-side comparison of sea ice thickness from 2021 and previous years.
Every day, the Alfred Wegner Institute in Germany merges weekly data from Cryosat with daily data from the Soil Moisture and Ocean Salinity satellite (SMOS) to generate a weekly-averaged product. As well as being used for forecasts, these combined data show that the volume of sea ice in the 2020-21 winter season was at its lowest since these sea-ice data products began in 2010. The image on the left shows sea-ice thickness on April 9-15, 2021, and the image on the right shows the sea-ice thickness on April 9-15, 2021, as compared to the average thickness on April 9-15 between 2011 and 2020. Image via ESA.
Satellite in Earth orbit above glistening white Arctic sea ice.
Artist’s concept of SMOS – the Soil Moisture and Ocean Salinity satellite – part of ESA’s Living Planet Program. This satellite makes global observations of soil moisture over Earth’s landmasses and salinity over the oceans. In this way, it can see and track Earth’s water cycle, the continuous exchange of water between our world’s oceans, atmosphere and land. Image via ESA.

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

Via ESA

LEAVE A RESPONSE

Please help keep this Site Going