The year 1710 was the coldest year recorded in Europe. Solar radiation had fallen to its deepest minimum in 4,000 years. This cold period led to reduced food production and a shrinking population across Europe. In Scandinavia, people moved west toward the sea, where they could sustain themselves by combining fishing with farming. The ocean had undergone a warming period over 50 years leading up to 1710. This ocean warming had created new growth in the marine ecosystem and provided better access to harvesting and fishing.

The cold climate period led to a cooling of the ocean until it reached a minimum around the year 1745. This caused the marine ecosystem and fisheries to be reduced to a minimum. Chilled oceans extended the cold climate period, and a colder sea surface affected the extent of glaciers. By 1745, glaciers along the coast reached their greatest extent in several thousand years. The turning point for ocean temperature in 1745 was caused by a new period of increased solar radiation. The ocean entered a warming period lasting 100 years until approximately 1850, allowing the marine ecosystem to grow imperceptibly over that century.

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Borgundfjord Fishing 

The Borgundfjord in North-Western Norway has one of the best spawning grounds for cod along the long Norwegian coastline. During the warm climate period up until the 1200s, fisheries created a trade center in Borgund. When the Little Ice Age arrived in the 1300s, the fisheries and the trade center disappeared over time. A new period of ocean warming toward 1850 created a new cod stock in Borgundfjorden. This led to the medieval town of Borgund being transformed over time into the fishing city of Ålesund. The city grew alongside the fisheries, and soon one could catch about 1 million cod per year. The fish were dried on every beach, and the fisheries created a maritime industry with shipyards and equipment suppliers. The entire community participated in catching more fish.

The turning point for ocean temperature in 1850 was linked to reduced solar activity. Solar radiation reached a new deep minimum around 1885, leading to a new cold climate period. This cold period caused reduced agricultural food production, which led to large portions of the North European population emigrating to America. The new cold climate period simultaneously led to a new cooling of the ocean until a minimum around 1910. During this period, the Møre-cod in Borgundfjord saw reduced recruitment. At the same time, better equipment was developed to maintain a catch of about 1 million cod per year. The collapse came in 1930, marking the end for the Møre-cod and Borgundfjord fishing.

The Great Herring Adventure 

Herring had been fished along the Norwegian coast for more than 1,000 years, but no one could explain why the herring appeared in specific periods. The last cold climate period within the Little Ice Age ended around 1885. Increased heat from the sun then created a new period of global warming toward a maximum around 1930. This led to ocean warming that peaked in the 1940s. Global solar warming had warmed the ocean over approximately 30 years, and this warming laid the foundation for a new herring stock. One of the best spawning grounds was on the Møre coast outside Ålesund, and this new stock became “the great herring adventure”.

The herring adventure hit my hometown of Ålesund. When I was 6 years old, I sold herring to housewives for 25 øre from a string of fish. We could follow the great adventure through the radio’s “fishery wave”. The herring catches were so large that fishing boats needed helpers to save the haul. The entire city participated in harvesting the “silver of the sea”. Those not out fishing worked in receiving stations, the fish industry, ship repairs, developing better boats, producing more effective gear, and creating better work clothes. School classes were given time off from lessons to unload herring at the docks.

The herring adventure was a golden age until the herring stock abruptly collapsed in 1966. The break was so brutal that no one could understand how it happened. Had the fishing industry overfished? Had scientists miscalculated, or had the fish disappeared on unknown migrations? Solar heat had peaked around 1930 and then took an upward trend, which was one reason ocean warming reached a turning point in the 1940s. When the great herring adventure began in the 1950s, ocean temperatures had already started a new cooling period lasting until the 1960s-70s. During this cooling period, new recruitment failed, and the herring stock collapsed.

Cod Stocks Through Good Years and Bad 

Cod stocks in the Barents Sea have created prosperity dating back to the Viking Age. At the same time, the “sea people” had learned to live with the fact that cod fishing was characterized by booms and busts. Global ocean warming until the 1940s also laid the foundation for a new large cod stock in the Barents Sea. When a new fishing fleet was built in the 1950s, the Barents Sea was already in a new period of cooling that lasted until 1979. This ocean cooling put new recruitment on hold, leading to the 1980s being the worst years ever for the fishing industry. From 1980, the sun created a new period of global ocean warming, providing the basis for a new modern fishing fleet. Global warming had created new growth in the cod stock heading toward the 2000s.

In 2023, a new alarm was sounded as the spawning stock had been on a downward trend since 2010. This led to annual quota reductions until reaching levels from the 1970s. Everything indicated that the ocean’s temperature had passed a turning point and was heading toward a repetition of the 1970s.

The Unknown Climate Machine 

The stories of the sea people are randomly selected examples among many similar stories over thousands of years. These stories illustrate the long-time delays between climate changes, ocean temperatures, ecosystems, and the rise or fall of civilizations. The climate changes imperceptibly over generations, giving us a feeling that climate change has a “normal” state, a normal state that might be subject to disruption from volcanoes, humans, or other sources. The stories of the Sea People suggest that the climate is driven by an unknown climate machine that slowly transforms ecosystems and civilizations.

We will here examine fact-based measurements of changes in nature. The question is whether variations in nature are characterized by the climate machine. Are the variations random or predictable? If they are predictable, we can calculate the climate’s past and future. We can calculate the climate’s turning points to adapt to the changes that will inevitably come.

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References

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6. Yndestad, Harald; Turrell, William R; Ozhigin, Vladimir. 2008. Lunar nodal tide effects on variability of sea level, temperature, and salinity in the Faroe-Shetland Channel and the Barents Sea. Deep Sea Research Part I: Oceanographic Research Papers 2008; Volum 55.(10) s.1201-1217 
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