1. Excited to announce the 6th installment of "2C: Beyond the Limit." To me, this is one of the most striking stories that we found. It’s about dramatic changes playing out vast stretches of the northwest Pacific region as (or so we put it) “climate dominoes begin to fall.”
2. This story is by @simondenyer, who runs the Post’s Tokyo bureau, with photos by @salwangeorges. Both traveled to Hokkaido, Japan’s most northern island, for this tale of salmon, ice, and frightening changes in the most dynamic sea ice system on Earth.
3. Here's a glimpse of the scene -- a view of the contested island of Kunashir from Hokkaido, across the Sea of Okhotsk. 
4. You probably haven’t heard of much – if anything – about climate change and the Sea of Okhotsk. While a group of researchers in Japan have been publishing for years on the dramatic transformations occurring here, their findings have not received a very widespread airing.
5. In a nutshell, here’s what they are. (With references!)
6. The Sea of Okhotsk, north of Japan and east of Siberia, is downwind from the coldest place in the northern hemisphere – Siberia’s “Cold Pole.” As a result, the Sea is home to the most powerful sea ice factory on Earth.
7. Indeed, it generates so much ice that much of it drifts all the way southward to Hokkaido, reaching the lowest latitude for sea ice anywhere. The ice is widely celebrated in Hokkaido, as you can tell in this image from a sea ice museum there.
8. Because of this extremely dynamic ice production – exceeding even what happens in any single location in Antarctica – the Sea of Okhotsk generates a powerful undersea current, as massive amounts of salt are expelled into the frigid water during the freezing process.
9. The salt makes the cold water even denser than it would be otherwise. And then, in a process that will be familiar to those who understand “overturning” in the North Atlantic, that dense water sinks, forming an an undersea current that flows out of the Sea of Okhotsk.
10. The water travels through the narrow Kuril Straits, and into the broader Pacific ocean. Key nutrients like iron, and also oxygen (cold water holds a lot), travel along with it.
11.Some studies on all of this here:
agupubs.onlinelibrary.wiley.com/doi/epdf/10.10…
link.springer.com/article/10.118…
researchgate.net/publication/23…
agupubs.onlinelibrary.wiley.com/doi/epdf/10.10…
link.springer.com/article/10.118…
researchgate.net/publication/23…
12. But this whole mechanism, which is crucial to the North Pacific, is being disrupted. Here’s where the chain of “climate dominoes” comes in.
13. The warming is very large at Siberia’s Cold Pole – we find 2.7C of long-term warming at Oymyakon, a village that has recorded the coldest temperatures in the Northern hemisphere (-67.7C!). That was back in 1933. (Gonna be hard to break that record now.)
Tweets 12 and 13 here as they seem to have possibly become detached from this thread
14. So the cold winds blowing across the Sea of Okhotsk are less cold now. And ice formation is, accordingly, declining – ice extent in the Sea has dropped about 30 percent in its peak months over the last 4 decades, according to the @nsidc.
15. The Sea of Okhotsk, too, is warming, most rapidly in its northern sectors closest to Siberia. Some regions, according to @berkeleyearth, even reach 3C of change.
16. That’s not true of the entire sea, but the warming is quite strong in its northern sectors, and then weaker as it stretches down towards Japan and Hokkaido, but still quite significant.
17. Scientists have published evidence suggesting that all of this is already having an effect on the broader north Pacific.
18. For instance, the “intermediate water” that originates in the Sea of Okhotsk is getting warmer, and as it gets warmer it is holding less oxygen. That’s been documented.
researchgate.net/publication/25…
researchgate.net/publication/25…
19. North Pacific oxygen levels in the intermediate depths are also in a fast decline, and scientists have suggested this may be linked to the changes in the Sea of Okhotsk.
agupubs.onlinelibrary.wiley.com/doi/full/10.10…
agupubs.onlinelibrary.wiley.com/doi/full/10.10…
20. Thus, there is good evidence from the warming of the water, from oxygen levels, and from the decline of sea ice, to suggest that the Sea of Okhotsk – which one expert called the “heart of the North Pacific” – is losing some of its “pumping” power, to continue the metaphor.
21. This is all a very big deal.
22. The effects are felt all the way down in Hokkaido, even though it is a fair distance from the most northern parts of the Sea of Okhotsk where the most dramatic changes are happening.
23. Less drift ice now reaches these southern shores, and that is a threat to a tourism industry that is built upon the truly magical scenes of ice that appear in winter.
24. Meanwhile, the culture of Hokkaido is all about its salmon – and the huge numbers of brown bears that feast upon them.
25. And the salmon that start their life journeys here go on to travel across much of the Sea of Okhotsk before eventually returning to Hokkaido years later – if they survive the entire journey.
26. As the warming has happened, the chum salmon catch has plummeted in Hokkaido but boomed in Russia farther north over the very same time period, the last 10 to 15 years or so.
27. As for all of the consequences in the broader North Pacific – we don’t know yet. But with the major changes occurring, there is considerable reason for worry.
28. In one of the first stories of this series, we showed that despite the 2 degrees C target being uniformly discussed as something to avoid in the future, about 10 percent of the globe has already reached or exceeded it. washingtonpost.com/graphics/2019/…
29. But what this story shows is that even in regions that have not reached this high level of warming yet – mainland Japan, or the north Pacific – the Earth's most rapidly warming regions can have a dramatic impact.
30. In this particular case, the story explains, there is a cascade, a chain reaction, starting in Siberia and eventually touching regions over a thousand miles away. There are long-distance effects and consequences.
31. It's a classic case of how, as we alter the climate, we are going to find surprising consequences that were not necessarily expected -- and that may be severe.
32. That's the thought I'll leave you with and refer you back to the story -- about the Sea of Okhotsk, its rapid changes, and their unsettling, long-range consequences. washingtonpost.com/graphics/2019/… /end
