Strange Sea Ice Data July End 2025

Before presenting the MASIE and SII results for July, a note about a strange thing in today’s Sea Ice Index report.  I have sent a note to them requesting an explanation for why the values have been altered from those in the dataset just two days ago.  When attempting to add into my spreadsheets the final two July days, I noticed that all the previous values were now different.  Exploring further, going back to beginning of 2024 all values had changed, some showing larger extents and many showing smaller ice extents than previous recorded.

For 2024 the new values added ice extents with the average day gaining slightly (47k km2).  But in 2025 so far, the average day lost (-57k km2) compared to the values two days ago.  Curiously, since March 14, 2025 all days had lower values at a daily rate of -75k km2.  In sum, the altered values in 2025 removed ~11M km2 of ice extents so far, and 10M km2 of that since March 14.  In the report below, I excluded the altered SII values awaiting news from NSIDC.

After a sub-par March maximum, by end of May 2025 Arctic ice closed the gap with the 19-year average. Then in June the gap reopened and in July the melting pace matched the average, abeit four days in advance of average. The chart shows the July Arctic ice extents on average decline from 9.7M to 6.9M km2. MASIE started July ~5M km2 in deficit to average and ended the month ~4M km2 down, continuing to melt about four days in advance of the average decline. SII matched MASIE the first half of July, then tracked slightly lower the second half.

The regional distribution of ice extents is shown in the table below. (Bering and Okhotsk seas are excluded since both are now virtually open water.)

Region 2025212 Day 212 2025-Ave. 2020212 2025-2020
 (0) Northern_Hemisphere 6555733 6941055 -385322 5880746 674988
 (1) Beaufort_Sea 944231 793206 151025 875454 68777
 (2) Chukchi_Sea 621236 555019 66217 533748 87488
 (3) East_Siberian_Sea 683122 751512 -68390 329453 353669
 (4) Laptev_Sea 329581 370847 -41266 61979 267602
 (5) Kara_Sea 32436 166826 -134390 95539 -63103
 (6) Barents_Sea 1131 29555 -28424 23940 -22808
 (7) Greenland_Sea 228078 296681 -68603 282403 -54325
 (8) Baffin_Bay_Gulf_of_St._Lawrence 117170 150751 -33581 35368 81801
 (9) Canadian_Archipelago 460908 547942 -87034 515499 -54592
 (10) Hudson_Bay 73633 139798 -66165 92861 -19228
 (11) Central_Arctic 3062678 3137162 -74483 3033706.07 28972

The table shows  most regions in deficit with Kara the largest, and Canadian Archipelago and Central Arctic also sizable.  Hudson Bay and Greenland Sea will lose the rest of their ice in upcoming weeks. Surpluses in Beaufort and Chukchi offset about 220k km2 of losses elsewhere.

Why is this important?  All the claims of global climate emergency depend on dangerously higher  temperatures, lower sea ice, and rising sea levels.  The lack of additional warming prior to 2023 El Nino is documented in a post NH and Tropics Lead UAH Temps Lower May 2025.

The lack of acceleration in sea levels along coastlines has been discussed also.  See Observed vs. Imagined Sea Levels 2023 Update

Also, a longer term perspective is informative:

post-glacial_sea_level

Illustration by Eleanor Lutz shows Earth’s seasonal climate changes. If played in full screen, the four corners present views from top, bottom and sides. It is a visual representation of scientific datasets measuring Arctic ice extents and NH snow cover.

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