Accumulated surface mass balance (SMB) 1 Sep 2024 to 31 Aug 2025 was 403.8 Gt (=km³), close to the average 1980-2025. SMB is snowfall - runoff, i.e. always positive. This is NOT the total mass balance TMB, which also includes iceberg calving and which shows ice loss for the 29th year in a row.

PLEASE NOTE: Data source for sea ice concentration and extent has changed. Beginning 1 July 2025, the Japanese AMSR2 is replacing the US SSMIS instrument for our sea ice concentration and extent products. SSMIS and AMSR2 differ by ±0.1 million km² or less with larger differences in summer.

𝐈𝐌𝐏𝐎𝐑𝐓𝐀𝐍𝐓 𝐍𝐎𝐓𝐄: The access to SSMIS data  from the US DMSP satellites is coming to an end. 𝐓𝐡𝐞 𝐚𝐜𝐜𝐞𝐬𝐬 𝐭𝐨 𝐝𝐚𝐭𝐚 𝐰𝐢𝐥𝐥 𝐞𝐧𝐝 𝐚𝐥𝐫𝐞𝐚𝐝𝐲 𝟑𝟎 𝐉𝐮𝐧𝐞 𝟐𝟎𝟐𝟓. We are working on the matter and try to find a replacement.

First large melt event of the year in Greenland.

🌐❄️ 𝗧𝗵𝗲 𝗻𝗲𝘄 𝗣𝗼𝗹𝗮𝗿 𝗣𝗼𝗿𝘁𝗮𝗹 𝘄𝗲𝗯𝘀𝗶𝘁𝗲 𝗶𝘀 𝗹𝗶𝘃𝗲! 🔗https://polarportal.dk/en/ Here it is: the updated 𝗣𝗼𝗹𝗮𝗿𝗽𝗼𝗿𝘁𝗮𝗹.𝗱𝗸 – your gateway to 𝗿𝗲𝗮𝗹-𝘁𝗶𝗺𝗲 𝗱𝗮𝘁𝗮 𝗼𝗻 𝗔𝗿𝗰𝘁𝗶𝗰 𝘀𝗲𝗮 𝗶𝗰𝗲 𝗮𝗻𝗱 𝘁𝗵𝗲 𝗚𝗿𝗲𝗲𝗻𝗹𝗮𝗻𝗱 𝗜𝗰𝗲 𝗦𝗵𝗲𝗲𝘁. The portal is powered by DMI, GEUS, DTU Space and DTU DTU Byg and supported by data from Asiaq and PROMICE.

The onset of the ablation season in Greenland is defined as the first of at least three days in a row with a surface mass balance below -1 km³ (= -1 gigaton). In 2025, this was on 15 June, 2 days later than the median 1981-2010. Top: SMB, 17 June 2025 Bottom: sum of daily SMBs since 1 Sep 2024

The onset of the melting season in Greenland is defined as the first of at least three days in a row with melting over more than 5% of the Greenland Ice Sheet. The median over the period 1981-2025 is on 26 May. This year, the melting onset was 12 days early, on 14 May, which is rank 11 of 45 years.

Within the next weeks, we will introduce a facelifted @polarportal.bsky.social (bye bye 90s design!) and also some new data! You always find data from @dmidk.bsky.social and our colleagues from #GEUS and @dtucryo.bsky.social there. Glad to say data is available on this side of the Atlantic.

After a brief slightly cooler period, high temperatures over the ice sheet again. Approaching the onset of the melting season.

Accumulated surface mass balance (SMB) 1 Sep 2023 to 31 Aug 2024 was 367.3 Gt (=km³), close to the average 1980-2024. SMB is snowfall - runoff, i.e. always positive. This is not the total mass balance TMB, which also includes iceberg calving. Greenland has lost ice every year since the mid-1990s.