I'm wondering now, whether what I had learned in #1 about nutrients accumulating on winter sea ice and providing feed to ocean creatures in spring melt in Antarctica isn't also true in the Arctic.

While the verdict on Antarctica's sea ice growth or shrinkage is still uncertain, the Arctic sea is in adaption mode for sure, ie., it is shrinking in age, in area covered and in thickness. Surely, the nutrient accumulation process on sea ice that impacts the ocean carbon sink, is also active in the Arctic. And ice IS shrinking there.
The Global Carbon Project reports a 4% lower growth of the ocean sink for 2021. (And 17% lower growth of the land carbon sink.) (Note, the sinks still grew in tandem with anthropogenic CO2 emissions, but they grew less. As if they were approaching some saturation threshold.)

And also worrying to the Carbon experts is that they find a now seemingly persistent trend of a negative imbalance in the carbon budget.
The imbalance is the calculation result of CO2 sources minus carbon sinks. If the imbalance is negative it can be due to CO2 sources being higher than estimated, or due to sinks being smaller than estimated - or both.

So, I'm all the more curious whether the nutrients-seaice process in the Arctic does exist and whether less ice growth in winter already negatively affects the ocean carbon sink.
... indeed, the cryosphere report states that on page 34. Well, there you go. Mystery solved.

On the side: sea ice-free Arctic will occur at least once before 2050. And the Arctic is now officially warming 4 times faster than global average, not 2-3 times faster as the previous official figure.
Depending on our leaders' emission policies, or rather, depending on our determination as climate activists to pressure our leaders to sufficient action wrt degrowth,
the Arctic summer can be ice free from June to November by 2040 or 2050.

Which lets me wonder how that'll impact Northern Hemisphere weather. Which path will a jetstream choose that is no longer "fuelled" by an ice-cold Arctic sea? Where will the highs and lows in air pressure form which in recent years caused stationary heatwaves or the very slow-moving deep Bernd in July 2021 with torrential rain over Belgium, Switzerland and Germany.
I can probably scholar-google that answer.
But getting my curiousity triggered is a gift on its own.

Maybe, by 2030, the lack of summer sea ice will create jetstream patterns every year like the one in 2019 when the french farmer burnt to death during harvest on his wheat field.

#Antarctica #Arctic #OceanCarbonSink #CarbonSink #SeaIce #GlobalCarbonBudget #GlobalCarbonProject