The Impact of Climate Change on Cold Ocean Outbreaks
Discover how the rise in planet-warming pollution is linked to the occurrence of 'killer events' in colder ocean regions, shedding light on the connection between climate change and extreme cold outbreaks.
New research reveals that marine life is not only being affected by ocean heat, but also by extremely cold events that are causing mass mortalities. These "killer events" on the opposite end of the temperature spectrum are likely linked to the same planet-warming pollution driving the climate crisis.
Concerns for marine life have been growing as the world's oceans have experienced unprecedented heat in the past year. Billions of crabs have vanished in the northern Pacific, sea lions and dolphins are falling ill, and iconic coral reefs are suffering from mass bleaching.
Ocean temperatures are rising, but at the same time, extremely cold upwelling events are also increasing in frequency and intensity. These events occur when strong winds and ocean currents bring cold water up to the surface, replacing the warm water that was there. This poses a threat to sea life, as reported in a study published in the journal Nature Climate Change on Monday.
Lead author of the study, Nicolas Lubitz, who is a researcher at James Cook University in Queensland, Australia, emphasized that climate change is a complex issue. It's not just about the warming of the globe, but it's also about how it is altering the way our oceans function.
Lubitz began his investigation upon hearing about the deaths of marine animals such as sharks, manta rays, and squids along the southeast coast of South Africa in March 2021. Over 260 marine animals from 81 different species perished in this single catastrophic event.
Coral bleaching in the lagoon of the Great Barrier Reef's Lady Elliot Island, on February 19, 2024.
Coral bleaching in the lagoon of the Great Barrier Reef's Lady Elliot Island, on February 19, 2024.
Rebecca Wright/CNN
Related article
Ocean heat is driving a global coral bleaching event, and it could be the worst on record
Seasonal upwelling events are common in that area, causing the water temperature to drop quickly. According to Lubitz, the March 2021 die-off was particularly severe due to the warmer water conditions prior to the event.
Lubitz explained that the winds shifted and the currents began to change slightly, a normal seasonal occurrence. Within just 24 hours, the temperature dropped by 11 degrees, leading to the extreme event.
The researchers studied killer upwelling events in the Indian Ocean’s Agulhas Current and the East Australian Current. They used 41 years of sea surface temperature data and 33 years of wind records to understand the impact of deadly cold ocean extremes.
According to the researchers, changes in the frequency and intensity of upwelling events could affect fishing communities in these areas. This could have economic and biodiversity implications for the regions.
According to research, the severity of a cold event is often related to how quickly the temperature decreases. When cold events persist for several days, as is happening more often now, marine animals like turtles and various fish species may experience hypothermia, physiological issues, or even death.
This image provided by NOAA shows a smalltooth sawfish. Endangered smalltooth sawfish, marine creatures virtually unchanged for millions of years, are exhibiting erratic spinning behavior and dying in unusual numbers in Florida waters. Federal and state wildlife agencies are beginning an effort to rescue and rehabilitate sawfish to find out why. (NOAA via AP)
A smalltooth sawfish, an endangered marine creature that has remained virtually unchanged for millions of years, is facing challenges in Florida waters. These creatures are showing unusual behavior patterns such as erratic spinning and experiencing higher mortality rates. In response, federal and state wildlife agencies are launching a rescue and rehabilitation effort to investigate the reasons behind these occurrences.
Related article
Six rare sawfish deaths in 7 days have scientists baffled amid bizarre Florida fish behavior
Lubitz had previously tagged bull sharks with a device that tracked their location, depth, and temperature in the ocean for another research project.
He explained, "This was crucial for our study as it allowed us to monitor the sharks' migration patterns. We observed that the sharks swam closer to the surface in upwelling areas to avoid the colder water from the depths, showing how the temperature profiles changed."
The findings from a recent study offer a plausible explanation for the numerous unexplained marine mortality events that have been observed globally, according to Ajit Subramaniam, a research professor at Columbia University's Lamont-Doherty Earth Observatory.
Subramaniam, who was not part of the research team, described the findings as unexpected and not commonly discussed. He emphasized the importance of this discovery as a reminder that the climate crisis has far-reaching consequences.
Editor's P/S:
The revelation that extreme cold events are also harming marine life alongside ocean heat is both alarming and sobering. It underscores the complexity and pervasive impact of climate change on our planet's ecosystems. While we often focus on the devastating effects of rising temperatures, it's crucial to recognize that the opposite end of the temperature spectrum can also be equally catastrophic.
The study highlights the need for a comprehensive understanding of how climate change is altering ocean dynamics. By exploring the interplay between warming and cooling events, we can better predict and mitigate the risks to marine life. Monitoring sea surface temperatures and wind patterns, as well as tracking the behavior of marine species, will be essential in developing adaptation strategies and safeguarding the health of our oceans.
