BornFromTheVoid

Recent changes in different sectors of the Arctic. Small losses generally balancing out the big gains in the Barents region

10.7C and 73mm, thanks

Alright @Timmytour and @Quicksilver1989, ye can keep the convo going here. I'll try to respond later this evening if I have time. But an important consideration about Greenhouse Gasses (GhGs) We know the warming is caused by GhGs because of how they interact with specific wavelengths of light. GhGs absorb and emit longwave (LW) radiation at certain frequencies which can be measured at the surface and in space. Shortwave radiation (sunlight) hits the surface, warms it and emits LW radiation (heat) back up. The GhGs then absorb certain parts of that LW radiation and re-emit a portion of it back to the surface. This increases the downwelling LW radiation and this increase has been observed by instruments at the surface. Conversely, because more of the LW radiation is being absorbed by the extra GhGs and sent back to the surface, there is less leaving the atmosphere and into space. This has also been observed by satellites. This is clear empirical evidence. We can even work out the energy balance of the planet (how much is going in vs going out) and we know there is a big imbalance currently caused specifically by GhGs. There are many other lines of evidence too, but to be clear, there is 100% no doubt that the warming is caused by GhG increases. Human driven climate change is as certain among climate scientists and evolution is among biologists. For most of the "well have they considered" type questions - yes, they almost certainly have been considered and there is likely hundreds of papers on the topic.

Might be best to take the conversation to the climate area. The climate questions thread could be appropriate.

6.8C or 6.9C are likely to be the final values, then anything down to 6.3C after corrections seems possible.

Latest weekly animation

Some bad fires in Killarney national park and on the Mourne mountains today Mourne Mountains

Here's the new sea ice poll for April. In last months poll, from 11 votes the average was 4.1 million km2 with a standard deviation of 0.5 million km2. Extent has varied between 9th and 3rd lowest over the last 3 weeks. Volume is at 3rd lowest on the latest update from PIOMAS, while the combined SMOS and CryoSat dataset has volume at lowest on record for the time of year. As a reminder, the minima since 2010 in millions of km2 from the daily NSIDC data are: 2020: 3.7 2019: 4.1 2018: 4.6 2017: 4.6 2016: 4.1 2015: 4.4 2014: 5.0 2013: 5.0 2012: 3.3 2011: 4.3 2010: 4.6 The thread will lock at midnight at the end of the month.

It looks likely that April will achieve something no year in the 2000s decade achieved - getting more than 2C below it's recent climatological average. The 1990s managed 5 such months, the 2010s had 3. Conversely, for months more than 2C above their recent climatology, the 1990s managed 14, the 2000s managed 13 and the 2010s had 9.

I won't bother with the graphs today, but a finish below 7C is now a 57% chance (with the GFS to the 28th, projections thereafter). Given the cold outlook for the final 2 days of the month and the likelihood of downward corrections, I'd estimate closer to 80% chance of a sub-7C finish.

A large crack stretching from the Bering Strait to the Laptev Sea, opening and closing in recent days. Sections of the central pack showing transient low concentration areas as dense cloud &/or temporary rainfall starts to occur.

Latest projections The chances of finishing: Close to average (8.5C to 9.5C) remains at to 0% (2 days ago 0%) Above average (>9.5C) remains at 0% (2 days ago 0%) Below average (<8.5C) remains at 100% (2 days ago 100%) The period of the 21st to the 26th is forecast to average 9.0C, which is 1.3C below the 91-20 average. Also, we're currently at 8 sub 0C minima for the month, which is the joint 4th most on record. Two days, the 10th and 11th, were barely above 0C, so might drop below after corrections, and the minimum tonight could also get close to freezing, taking the total to 11 days, the 2nd most on record (after 1917 with 12).

Latest projections The chances of finishing: Close to average (8.5C to 9.5C) is to 0.0% (3 days ago 0.4%) Above average (>9.5C) remains at 0.0% (3 days ago 0.0%) Below average (<8.5C) is to 100% (3 days ago 99.6%) The period of the 19th to the 24th is forecast to average 8.7C, which is 1.2C below the 91-20 average.

Latest PIOMAS volume is out to mid April. 2021 is 3rd lowest on record, above 2017 & 2018. It's also: 8,400 km³ below 1980s 7,000 km³ below 1990s 3,700 km³ below 2000s 500 km³ below the 2010s average Volume dropping during the first half of April for only the 3rd time, and it was the largest drop on record. Regionally, volume is not doing as well along the Russian Arctic coastline, from 5th most volume since 2000 at the end of March to 9th most now. For the central Arctic, 2021 has gone from 2nd to 3rd lowest (although it's basically a tie with 2013 for 2nd lowest) And here's the regional comparison with 2020 and the 3 lowest volume years on record.

This weeks slow sea ice animation Losses across the Pacific side of the Arctic almost balanced out by a large wind-driven increase east of Svalbard. We can see the first signs of melt in Hudson Bay also & large leads opening along the Siberian side - sign of a very mobile central pack.

Latest projections The chances of finishing: Close to average (8.5C to 9.5C) is to 0.4% (2 days ago 2.4%) Above average (>9.5C) remains at 0.0% (2 days ago 0.0%) Below average (<8.5C) is to 99.6% (2 days ago 97.6%) The period of the 16th to the 21st is forecast to average 7.5C, which is 1.5C below the 91-20 average.

Latest projections. The chances of finishing: Close to average (8.5C to 9.5C) is to 2.4% (2 days ago 1.6%) Above average (>9.5C) remains at 0.0% (2 days ago 0.0%) Below average (<8.5C) is to 97.6% (2 days ago 98.4%) The period of the 14th to the 19th is forecast to average 7.0C, which is 1.7C below the 91-20 average.

Here's the blog post mentioned earlier where I take a look at the upcoming melt season. 2021 Arctic Sea Ice Melt Season Outlook WWW.NETWEATHER.TV Samual Hayes explores the trends and the main influencing factors as the Arctic Sea Ice Melt season for 2021 gets underway. Obviously it's a little shortened and leaves out some features (such as the uncertainty in volume derived from models vs observations which may be very important this year) but as an basic overview it's hopefully ok.

Samual Hayes explores the trends and the main influencing factors as the Arctic Sea Ice Melt season for 2021 gets underway. Read the full article

They do occur (2006 was the closest to this year) but they've never been quite this big in early April before. Agreed though, winds are shifting at the moment so it's likely to close up again. Something else interesting, is that the Central Arctic hasn't yet fully frozen over this year. This has happened only twice before up to this point, in 2018 and 2016. Anywho, on a separate note, different things going on around the Arctic. On the Pacific side, ice melt in the Sea of Okhotsk is slower than normal, with the current the rank rising from 16th to 21st lowest in the last 7 days. The Bering Sea has even increased ice cover, going from 8th to 12th lowest. Meanwhile, on the Atlantic side, sea ice cover in the Barents sea is plummeting, going from 10th to 4th lowest in 7 days. Melt in the Kara Sea has started early too, going from fully frozen to 4th lowest extent. Finally, extent in the Central Arctic continues to drop, remaining lowest on record for the time of year & the lowest ever recorded in the first half of April. Overall were 5th lowest on the 5 day average too, and essentially joint 2nd lowest (with 2020 and 2018) in the single day extent values.

With open water north of both Svalbard & Franz Joseph Land, the 5 day running sea ice extent is now lowest on record for the central Arctic. As winds shift, it's likely that this will change, but it also highlights how unusual large areas of open water this far north are atm.

Latest projections The chances of finishing: Close to average (8.5C to 9.5C) is to 1.6% (2 days ago 3.6%) Above average (>9.5C) remains at 0.0% (2 days ago 0.0%) Below average (<8.5C) is to 98.4% (2 days ago 96.4%) The period of the 12th to the 17th is forecast to average 4.5C, which is 3.2C below the 91-20 average. The absolute highest outcome now is 8.7C, so it's safe to rule out anything above 9C.

Here's the slow animation for the week.

Similar with the CET maxima. The record high maxima on the 3rd, 23.5C (in 1946), is the 4th highest for the whole month. It's also warmer than any of the record maxima in the last 9 days of April. I guess it highlights the potential for maxima in the mid 20s throughout April