Field notes on sea-ice.

Every PenguinTracker dispatch tagged sea-ice. 6 posts.

1. 2026-08-14 · method · sea-ice · data

   Mertz Glacier's rising sea ice is a step, not a trend

   We asked all 5,686 fitted measurements on this site which year they changed level. One answer cost us a published number, and it is now corrected in public.

2. 2026-08-14 · penguins · sea-ice · antarctica

   Bear Peninsula: the sea ice now leaves 90 days early

   At one emperor penguin colony in Marie Byrd Land the sea ice season has gone from 322 days a year to 207, and it has shortened at both ends at once.

3. 2026-08-13 · method · sea-ice · penguins

   The Antarctic breeding failure a satellite could not see

   Our sea ice metric reproduced five published emperor penguin breeding failures and completely missed a sixth. The miss is the more useful result.

4. 2026-08-12 · penguins · sea-ice · antarctica

   Emperor Island, the one colony known to have been lost

   Emperor Island in Marguerite Bay held emperor penguins from 1948 to about 2009. Its sea ice season is 75 days shorter, and it is shorter at one end.

5. 2026-08-12 · method · sea-ice · data

   How a 1980s satellite invented an Antarctic sea ice trend

   The sensor that flew before 1988 reads several points low near coasts. Correct for it and 34 emperor colony sea ice trends fall to 10. Here is the proof.

6. 2026-08-11 · sea-ice · antarctica · data

   Antarctic sea ice is the 4th lowest on record for 9 August

   Antarctic sea ice stands at 16.085 million square kilometres, the 4th lowest reading for 9 August in a 48 year satellite record. What that number means.