Salt might seem simple, but it plays a massive role in our weather and climate.
Researchers from top Canadian and German science centers have dug into this salty mystery and uncovered some surprising ways that sea salt shapes our climate.
For a long time, experts have been puzzled about why Europe went through a deep freeze hundreds of years ago, known as the Little Ice Age.
This chilly time stretched from the 1400s to the 1800s and caused a lot of hardship, including failed crops and widespread disease.
While scientists have studied this period extensively, they’ve had a tough time figuring out exactly what kicked off the colder climate.
Dr. Anastasia Zhuravleva, the study’s lead author, shares that learning about past climate quirks can help us understand what might happen as the Earth gets warmer because of human activities.
She suggests that while a lot of focus has been on the icy northern waters and how fresh and salty water mixes there, the warm tropical Atlantic Ocean could be just as influential.
The research team scooped up sediment from the ocean floor in the southern Caribbean to get clues about the ocean’s past temperature and saltiness.
They examined tiny marine fossils, which tell a lot about the sea conditions they lived in long ago.
What they found was striking: the Caribbean sea surface cooled down by about 1 degree Celsius during the Little Ice Age.
This might not sound like much, but for that part of the world, it’s huge. This cooler sea was linked to drier conditions on land, which coincided with tough times for the ancient Maya civilization.
The team noticed that when Europe was stuck in the deep freeze, the Caribbean sea was extra salty, and the ocean currents were weak.
This saltiness matters a lot because it helps keep the waters in the far north dense and heavy, which is a big deal for the ocean’s conveyor belt-like currents. These currents are what bring warm water from the Gulf Stream to Europe, giving it a relatively cozy climate.
Their findings suggest that any change in the flow of salt from the tropics towards the north can either make cold events like the Little Ice Age worse or help warm things up by boosting those vital ocean currents.
The study hints that a slowdown of the Gulf Stream could be happening right now, partly because of the warming caused by human activities. Since this current is a big climate player, a weaker Gulf Stream could mean changes not just locally but globally.
Understanding how these different climate pieces fit together has been a puzzle. Now, thanks to this research, we know that the movement of salt across the oceans is a crucial piece of that puzzle.
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