Recent research has uncovered the pivotal influence of the distribution of sea salt on the Earth’s climate, establishing a connection between historical cold phases such as the Little Ice Age and alterations in ocean salinity and flow patterns. This investigation underscores the synergy between tropical zones and subpolar regions, highlighting the crucial role of saline circulation in the climate equilibrium of the Northern Hemisphere.
The study delves into the relationship among ocean salinity, currents, and the broader climate.
A collective effort by scientists from Dalhousie University in Canada, GEOMAR Helmholtz Centre for Ocean Research Kiel, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), and MARUM – Center for Marine Environmental Sciences at the University of Bremen has shed light on the essential function that the movement of ocean salt has in climate regulation globally.
The researchers have investigated natural climate variations, like the Little Ice Age — a period spanning from the 15th to the mid-19th century — which resulted in severe outcomes including poor harvests, famines, and disease across Europe. Although extensively studied, the precise climatic drivers of this epoch remain debated.
“Examining past natural climate variations aids in comprehending the dynamics and mechanisms that could be set in motion by anthropogenic global warming,” states Dr. Anastasia Zhuravleva, the study’s principal investigator. Initially a doctoral candidate at GEOMAR, Dr. Zhuravleva was honored with the Annette Barthelt Prize for her thesis in 2019 and subsequently pursued post-doctoral research at GEOMAR and Dalhousie University, where the study reached its fruition.
The Tropical Atlantic’s Significance
“Inquiries typically focus on increased sea ice coverage and freshwater dilution in the North Atlantic as instigators of previous cold intervals, yet phenomena in the tropical Atlantic are equally significant,” remarks Dr. Zhuravleva. Dr. Henning Bauch, a paleoclimatologist at AWI and GEOMAR, a study initiator and contributor, notes, “There is scant data on these recent climatic events in the subtropical-tropical Atlantic and their implications for the Northern Hemisphere, which our research addresses.”
The team has probed sediment samples from the southern Caribbean to reconstruct surface water salinity and temperature over the past 1700 years. This included analyzing isotopic and elemental contents in the calcite shells of plankton.
Examining Climate Anomalies and Their Effects
The data indicate a cooling of about 1°C during the Little Ice Age. “This temperature shift is quite marked for this region,” indicates Dr. Mahyar Mohtadi, a co-author of the study and leader of the Low Latitude Climate Variability group at MARUM. A notable cold snap in the 8th and 9th centuries was also identified, correlating with decreased rainfall in the tropical Atlantic, droughts in the Yucatan Peninsula, and the downturn of the Classical Maya civilization.
Moreover, the investigation showed that these cooler periods in the North Atlantic and Europe coincided with weaker ocean circulation and higher Caribbean salinity. “The transfer of tropical salt to the northern latitudes is vital for maintaining dense surface waters in the North Atlantic, which is crucial for the stability of large-scale oceanic circulation, including the Gulf Stream’s warmth that moderates temperatures in Europe,” states Dr. Bauch.
The historical data facilitates understanding the transatlantic link. Initial coolings may stem from volcanic activity, reduced solar output, and sea ice-ocean feedback loops in the north. The research provides evidence that reduced salt transport to the northern latitudes can intensify and extend these climatic occurrences. On the other hand, a slow northward movement of saline anomalies from the tropics can heighten subpolar North Atlantic surface density, potentially boosting the northward flow of warmth by ocean currents, thereby softening temperatures across Europe and North America.
“Models have predicted such a salt feedback mechanism, and it has been hypothesized for the Little Ice Age. However, due to the lack of tropical ocean data, these hypotheses have hitherto relied on less direct precipitation records,” Dr. Zhuravleva explains.
There are indications of the Gulf Stream’s weakening, with human-driven warming being a probable cause. The ramifications of this shift are expected to be widespread. The degree to which different climatic drivers interplay remains a question. The present study affirms that the meridional transport of salt is a key element in these complex processes.
Reference: “Caribbean salinity anomalies contributed to variable North Atlantic circulation and climate during the Common Era” by Anastasia Zhuravleva, Henning A. Bauch, Mahyar Mohtadi, Kirsten Fahl, and Markus Kienast, published on 3 November 2023 in Science Advances.
DOI: 10.1126/sciadv.adg2639
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Frequently Asked Questions (FAQs) about ocean salinity climate influence
How does ocean salinity affect global climate?
Ocean salinity plays a crucial role in regulating the Earth’s climate by affecting ocean current patterns, which in turn influences global weather systems and temperature distribution. The study links variations in ocean salinity with historical cooling events such as the Little Ice Age, demonstrating that shifts in salt distribution can impact climate stability across the Northern Hemisphere.
What was the Little Ice Age and its connection to ocean salinity?
The Little Ice Age was a period from the 15th to the mid-19th century characterized by cooler temperatures, leading to significant consequences like famines and diseases in Europe. This study suggests that changes in ocean salinity and circulation patterns during this period may have contributed to the global cooling observed at that time.
Who conducted the research on ocean salinity and climate change?
The research was conducted by a collaborative team from Dalhousie University in Canada, GEOMAR Helmholtz Centre for Ocean Research Kiel, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), and MARUM – Center for Marine Environmental Sciences at the University of Bremen.
What does the new study reveal about historical climate anomalies?
The study reveals that historical climate anomalies, such as the Little Ice Age, coincide with changes in sea surface temperature and salinity in the tropical Atlantic, which are connected to broader climatic impacts like weakened ocean circulation and shifts in weather patterns in the Northern Hemisphere.
What are the implications of the study’s findings on current climate change understanding?
The findings imply that the transport of salt in ocean currents is integral to understanding and predicting climate patterns. This has modern implications as it suggests that current changes in ocean salinity due to human-induced warming may have significant and lasting impacts on global climate.
More about ocean salinity climate influence
- Understanding Ocean Salinity and Climate
- Impacts of the Little Ice Age
- Dalhousie University Climate Research
- GEOMAR Helmholtz Centre for Ocean Research
- Alfred Wegener Institute Research
- MARUM – Center for Marine Environmental Sciences
- Ocean Currents and Climate
- Science Advances Journal
6 comments
did anyone catch that bit about the Gulf Stream weakening, that sounds like serious trouble for climate if it’s true
I read this article twice and still amazes me… the ocean’s basically driving the weather and we’re just living in it, that’s wild
Does this mean that if we could control the ocean’s salt, we could sort of control the climate, seems a bit of a stretch but hey what do i know
really interesting how they’ve linked ocean salt levels to big climate changes, never thought about it like that before
interesting study but theres a lot more to climate than just salt right, like co2 emissions gotta be a bigger deal for global warming
so if i get this right, the little ice age might’ve been caused by less salt in the ocean? that’s nuts