New research aims to explain why sea ice is melting so fast

NASA researchers just wrapped up a never-before-done experiment, measuring how aerosols interact with sea ice. WBZ-TV's Jacob Wycoff reports.

[OldScientist]

The Arctic minimum summer sea ice trend is zero for the past 18 years. In the past few years it was almost as high as 1995. The probability that this could be due to chance has now dropped to 10% (after Swart et al calculations, 2015). If the hiatus continues until 2027, it will become statistically significant (p<0.05, or less than 5%) and no longer explainable by chance. Using National Snow and Ice Data Centre (NSIDC) information for September minima (million km²):
2007 4.16
2008 4.59
2009 5.12
2010 4.62
2011 4.34
2012 3.39
2013 5.05
2014 5.03
2015 4.43
2016 4.17
2017 4.67
2018 4.66
2019 4.19
2020 3.82
2021 4.77
2022 4.67
2023 4.23
2024 4.28
Plot the trend line for this data and it will be flat. ZERO net change in 18 years. The linear trend since 2007 is indistinguishable from zero ( around -0.17% per year ).
In the early 1950s the sea ice concentration anomaly was lower than it is at present. The sea ice anomaly then rose during the 50s, 60s and 70s. This was followed by a decline. This is demonstrated in Arctic and Antarctic Research Institute (AARI) data, which is based on historical sea ice charts from several sources (aircraft, ship, and satellite observations).
The AARI data shows the sea ice concentration anomaly was lower in 1952 (-5%) than 2005 (-3%). The anomaly increased in the 50s, 60s and 70s. In the 80s, 90s and early 2000s it decreased. Since 2007 the trend has been flat.
JAXA (Japanese Aerospace Exploration Agency) satellite data from 2002 to 2024 Arctic Sea Ice Extent (365 day running average) shows no noticeable trend with values close to 10, 000, 000km² throughout. Their minimum extent for daily values was in 2012. No other year since has come close.
MASIE (Multisensor Analyzed Sea Ice Extent - Northern Hemisphere) shows something similar to JAXA. From 2005 to 2024 Arctic Sea Ice Extent (365 day running average) shows no noticeable trend with values close to 10, 000, 000km² throughout. Their minimum extent for daily values was in 2012. Again no other year since has come close. It also shows a marked increase in Ice in the Greenland Sea since 2018.
Polyakov et al (2003) show "ice extent (1900-2000) in the Kara, Laptev, East Siberian, and Chukchi Seas provide evidence that long-term ice thickness and extent trends are small and generally not statistically significant". Trend -0.5% per decade (±0.7%). They also noted "the Arctic temperature was higher in the 1930s–40s than in recent decades, and hence a trend calculated for the period 1920 to the present actually shows cooling."
Zhang (2021) showed there was no trend for Arctic sea ice volume since at least 2010, and observes that ice draft increased from 1995 onwards. Including more recent satellite data from Cryosat-2 (2010-2023)reveals the Arctic ice volume minimum (Oct-Nov) is increasing at 56km³/yr (Kacimi and Kwok, 2024).
Vinje (2001) shows a deceleration in the rate of ice loss from 1864 to 2000.
Recent sea ice extent is very high when compared to the last 10, 000 years. Also changes in sea ice extent and the speed of those changes were greater in the past (Stein et al, 2017).
NOAA's Global Time Series Average Temperature Anomaly monthly data (1995-2004) for the Arctic region shows the peak anomaly occurred in January 2016 (+4.99°C), another El Niño year, and the trend is now downwards (-0.42°C per decade) as of June 2024.
HadCRUT4 Arctic (70N - 90N) monthly surface air temperature anomalies record (1920-2021) shows the greatest number and magnitude of positive temperature anomalies occurred between 1930-49. All anomalies in excess of 5°C, including +7°C (referenced to 1961-1990) are from that period. No temperature anomalies from 2000-2019 exceeded 5°C. It shows no decade warmed faster than the 1930s and the current 'warming' finished in 2005.
JRA55 SAT (2010-2020) shows most of the Canadian Arctic and Greenland cooling with parts of Canada cooling by 3°C and western Greenland cooling by 2.5°C in a decade.
KNMI data (Twentieth Century Reanalysis V2c, 1851-2011, 68°N-80°N, 25°W-60°W, so Greenland) shows the most pronounced warming took place in the 1870s, and when comparing temperature anomalies, highest are in the 1930s and comparison of that period with recent temperature anomalies shows no net warming.