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Gulf Stream’s Fate Influenced by Melting Greenland Ice Sheet

The Gulf Stream’s future hinges on Greenland’s ice melt. Modern iceberg calving rates match past events, potentially slowing crucial ocean currents due to climate change.
Gulf Stream's fate to be decided by climate 'tug-of-war'

The future of the Gulf Stream could hinge on a “tug-of-war” between two distinct types of melting occurring on the Greenland Ice Sheet, according to a recently published study. The research conducted during the last ice age, ranging from 16,800 to 60,000 years ago, shows that fleets of icebergs breaking off from the coast of North America led to significant weakening of vital ocean currents.

Modern-Day Iceberg Calving

The study, published on May 30 in the journal Science, found that current iceberg calving rates from the Greenland Ice Sheet match those of some past events. However, runoff from Greenland’s coasts could prevent such disruption. “We’re primarily worried about the tug-of-war between the more effective yet decelerating ice discharge and less effective accelerating runoff,” reports lead researcher Yuxin Zhou, a postdoctoral scientist at the University of California, Santa Barbara.

Current Concerns

The Atlantic Meridional Overturning Circulation (AMOC), which includes the Gulf Stream, regulates the climate by transporting nutrients, oxygen, and heat from tropical waters to the north and cold water south. The AMOC can exist in two stable states: a stronger, faster one that we rely on today, and another that is much slower and weaker. Climate change is disrupting this flow by causing freshwater from Greenland’s melting ice sheet to make the water less dense and less salty. This has led to an increasing number of studies suggesting that the current is slowing and could be veering toward collapse.

Icebergs breaking off from the Laurentide Ice Sheet, which dominated North America during the last Ice Age, are known as Heinrich events. The present-day cause of this melt is climate change. During the last glacial maximum, a combination of ocean heating and the accumulation of ice on the sheet likely caused the melting. This led to icebergs sliding into the sea and freshwater cascading from the shelf, both of which weakened the AMOC significantly over a few hundred years.

Comparing Past and Present

To determine if present-day iceberg calving from Greenland could trigger an AMOC collapse, Zhou and his team studied sediment layers deposited by past Heinrich events. The researchers used thorium-230, a form of the radioactive element found in seawater and diluted by fresh meltwater from icebergs, to compare their findings with predicted ice outflow from Greenland. The researchers established that the modern-day climate change impact, traced since the Industrial Revolution, is comparable to a mid-range Heinrich event.

However, there are crucial differences between the ice age and now. The AMOC had already started slowing down before the icebergs began to calve during the last ice age. In contrast, despite showing more variability than previously thought, the AMOC is currently in a “pretty healthy state” without significant slowdown, Zhou said.

AMOC’s Future Depends on Tug-of-War

According to Zhou, the changes we’re seeing today are governed by the relationship between iceberg calving and freshwater melt directly from the shelf. Icebergs play the most significant role in this slowdown, with runoff playing a secondary role. While runoff does cause some slowdown, it also hinders iceberg production, creating the tug-of-war that will decide the future of the AMOC.

However, if the AMOC is considered to be starting from a stronger position today than it did in ancient times, there may be a cause for cautious optimism, Zhou notes. But the inclusion of other influences from ocean and Arctic warming in future studies could alter this perception.

There are still many factors we need to understand for more accurate predictions of future AMOC behavior, warns David Thornalley, a professor of ocean and climate science at University College London. “But there are enough reasons to be concerned about the AMOC, and we should apply the precautionary principle — we really don’t want to experience first-hand the climate impacts of an AMOC collapse. It’s one of many climate impacts we should do all we can to avoid.”

Original Story at www.livescience.com

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Mississippi River Faces Persistent Saltwater Intrusion, Region Seeks Long-Term Solutions



For the third consecutive year, the Mississippi River is experiencing significant saltwater intrusion, prompting local communities and environmental experts to search for sustainable solutions. This recurring issue arises as the river’s flow decreases, allowing saltwater to move upstream and threaten drinking water supplies. The U.S. Army Corps of Engineers is actively involved in addressing this problem, employing temporary measures like saltwater barriers to mitigate the impact on affected areas.



Saltwater infiltration poses serious risks to public health and agriculture, as freshwater sources become compromised. The situation is exacerbated by prolonged periods of drought, which have reduced freshwater flow in the Mississippi River. According to the National Weather Service, drought conditions have worsened due to climate change, increasing the frequency and severity of saltwater intrusion events.



Local authorities are collaborating with federal agencies to explore permanent solutions. Among the proposed strategies are enhanced levee systems and improved water management techniques. The U.S. Army Corps of Engineers is evaluating the feasibility of long-term infrastructure projects to prevent further saltwater encroachment. Additionally, community leaders are advocating for increased funding to support these initiatives and safeguard the region’s water resources.



The impact of saltwater intrusion extends beyond drinking water concerns, affecting local ecosystems and agricultural productivity. Farmers in the region have reported crop damage due to elevated salinity levels in irrigation water. The Natural Resources Conservation Service is working with farmers to implement adaptive practices, such as planting salt-tolerant crops and improving soil management techniques.



As the Mississippi River continues to face challenges from saltwater intrusion, stakeholders emphasize the importance of collaborative efforts and innovative solutions. The ongoing threat underscores the need for comprehensive planning and investment to protect one of America’s most vital waterways from the impacts of climate change and environmental stressors.

November 19, 2024



Environmental activists have raised concerns over the fossil fuel sector’s significant impact on COP29, the latest United Nations Climate Change Conference. Activists argue that the industry’s presence diverts focus from critical climate actions.



The conference, designed to promote global climate agreements, faces criticism for allowing fossil fuel companies to participate extensively. Environmental groups claim these companies undermine efforts to reduce carbon emissions and transition to renewable energy sources.



According to Climate Action Network, fossil fuel representatives have increased their lobbying activities, aiming to weaken climate policies. These industries allegedly influence negotiations, leading to watered-down commitments that fail to address the urgency of climate change effectively.



Experts suggest that the influence of these companies stems from financial contributions and longstanding relationships with decision-makers. Critics argue that this affects the conference’s ability to enforce meaningful climate change regulations.



During the event, several protests highlighted the need for transparency and a stronger focus on sustainable energy solutions. Activists are calling for increased participation of renewable energy stakeholders in future conferences.



The controversy surrounding fossil fuel involvement at COP29 underscores the ongoing challenge of balancing industrial interests with the global imperative to combat climate change.



November 19, 2024