Carbon dioxide (CO₂) averaged about 427 ppm in December 2025

10 years ago December averaged about 402 ppm

Data available at https://gml.noaa.gov/ccgg/trends/

#Arctic sea ice concentration trends in January are only confined to the outer edges of the Arctic Ocean, such as the Barents-Kara Seas, Greenland Sea, Baffin Bay, and Sea of Okhotsk.

Sea ice concentration = fraction of ice-cover. For more info: https://doi.org/10.1175/BAMS-D-25-0104.1

A summary overview showing the standardized anomalies of annual #Arctic sea ice extent by region - now updated through 2025

[Data via NSIDC; Graphic available at https://zacklabe.com/arctic-sea-ice-figures/. Bright blue = max year, bright red = min year, vertical lines = 2007/2012/2016/2020/2025]

2025 was the hottest year on record for ocean heat content. Unfortunately, we now say this every year. 🥹

"In addition to setting a new record in 2025, the global ocean continues to show sustained and intensified warming."

+ #OpenAccess Study: https://doi.org/10.1007/s00376-026-5876-0
+ Data: http://www.ocean.iap.ac.cn/

Most of the #Arctic is experiencing warming temperatures over the last four decades in January. This is largest in the Barents Sea region and corresponds to losses of sea ice cover (turbulent heat fluxes).

Data from @CopernicusECMWF ERA5 reanalysis. More info: https://doi.org/10.1175/BAMS-D-25-0104.1

My monthly #Arctic temperature graphics are now updated for December 2025. Another unusually warm month. See: https://zacklabe.com/arctic-temperatures/ #DataViz #SciComm #OpenScience #OpenData

Last year was obviously the warmest on record for the North Pacific Ocean...

This graph shows the average for a band across the midlatitudes for every year from 1854-2025 using NOAA ERSSTv5 data.

2025 observed the lowest #Arctic sea-ice extent AND the lowest sea-ice volume for their yearly average values. This comes as no surprise to me as the polar environment continues to change. The consequences are far-reaching.

More graphics and stats already on my website (always free to share): https://zacklabe.com/arctic-sea-ice-figures/

Have a nice weekend! Here's your Friday ice update - #Arctic sea ice extent is currently the 4th lowest on record (JAXA data)...

• about 190,000 km² below the 2010s mean
• about 780,000 km² below the 2000s mean
• about 1,340,000 km² below the 1990s mean
• about 1,780,000 km² below the 1980s mean

More graphics: https://zacklabe.com/arctic-sea-ice-extentconcentration/

Modeled reconstruction of December #Arctic sea ice volume since the year 1901 - comparison between PIOMAS-20C and PIOMAS data sets now updated through 2025 (new record low)...

Data information available at https://doi.org/10.1175/JCLI-D-19-0008.1

Just in - "According to Climate Central, 2025 ranks as the third-highest year (after 2023 and 2024) for billion-dollar weather and climate disasters — with 23 such events costing a total of $115 billion in damages."

+ Interactive graphics/data: https://www.climatecentral.org/climate-services/billion-dollar-disasters
+ Climate Matters article: https://www.climatecentral.org/climate-matters/2025-in-review

Last month's total #Arctic sea ice volume averaged the *lowest* on record for the month of December...

More at https://zacklabe.com/arctic-sea-ice-volumethickness/

A comparison between recent satellite-derived sea ice observations and a reconstruction of ice extent since 1850 for the month of December. 2025 was a record low.

Data from https://doi.org/10.7265/jj4s-tq79

The first week of the new year is already flying by. Here's a look at how temperatures have changed around our planet over the last four decades in January...

Data from https://doi.org/10.24381/cds.f17050d7

Watch 100 years of December sea surface temperature anomalies updated through 2025. There's a lot of year-to-year variability, but a clear long-term warm signal is evident over time due to human-caused climate change.

Data from https://psl.noaa.gov/data/gridded/data.noaa.ersst.v5.html

Looks like this data was quietly updated in the fall for the latest numbers through 2024 - Annual Greenhouse Gas Index (AGGI) produced by NOAA (https://gml.noaa.gov/aggi/aggi.html)...

It is now up to a 54% increase in the influence of greenhouse gases in the atmosphere since 1990 (AGGI = 1.54; heat trapping)

Have a great week! Here's your Monday ice update - #Arctic sea ice extent is currently the 2nd lowest on record (JAXA data)...

• about 450,000 km² below the 2010s mean
• about 1,000,000 km² below the 2000s mean
• about 1,570,000 km² below the 1990s mean
• about 2,000,000 km² below the 1980s mean

More graphics for download: https://zacklabe.com/arctic-sea-ice-extentconcentration/

Check out the changes in January #Arctic sea ice thickness by decade...

Data information: https://climatedataguide.ucar.edu/climate-data/pan-arctic-ice-ocean-modeling-and-assimilation-system-piomas

Last month was statistically tied for the 5th lowest #Antarctic sea ice extent on record for the month of December.

This was 1,190,000 km² below the 1981-2010 December average. Data from https://nsidc.org/data/seaice_index

#Arctic air temperature rank by month over the satellite era - now updated through all of 2025

+ Ranks: 1=warmest (red), 47=coldest (blue)
+ Download higher resolution: https://zacklabe.com/arctic-temperatures/