Due to global warming, the oceans are swiftly warming and sea levels are elevating. With the help of satellites, the change in the speed of ocean currents over 30 years can be easily observed. ‘Ocean eddies’ are the circular motions in the water that be observed in water from aerial view. They can occur between 10 – 100 km across and are found all over the oceans. The particularly rich areas in eddies include Gulf Stream in North Atlantic, Kuroshio Current of North Pacific Ocean, Southern Ocean, East Australian Current, and Antarctica. These oceanic meso scale eddies have a deep role in mixing tracers like heat, carbon, and certain nutrients, thus moderating climate regionally and globally.
Satellites orbiting Earth are used to trace the small changes occurring in the surface of the sea, and through proper data analysis, the change in sea surface elevation is translated into ocean flow speed, which predicts the strength of ocean eddy. Josué Martínez-Moreno studied how ocean currents have become more energetic over huge parts of the ocean. The study is published in the journal Nature Climate Change. They statistically showed a significant rise in ocean eddy activity worldwide. They discovered an obvious change in the distribution and strength of oceanic eddies, and such changes have not been observed before.
Moreno’s team used satellite data from 1993 to 2020, to analyze changes in the strength of oceanic eddies worldwide. They found that regions having abundant eddies are getting even richer, eddies are recombining approximately 5% more energetic with every passing decade. The most obvious change is observed in the Southern Ocean, with a massive 5% rise per decade was detected in the oceanic eddy activity, making the Southern Ocean a hot spot for ocean heat uptake and storage of carbon.
The conclusion about eddy can be made only by sparse ocean measurements or by limited satellite records, which over decades has become ample enough for researchers to draw robust conclusions regarding long-term trends of eddy behavior. And to make a better and more accurate conclusion, more advanced tools should be invented.
The prime role of oceanic eddies is for the climate, as it regulated the mixing and transportation of heat, carbon, nutrients, and ecological community (flora and fauna) in the ocean. Therefore, the work of Moreno could have a wide-ranging implication on the climate of the future. It is well established that the Southern Ocean’s eddies can affect the overturning circulation of the ocean. Consequently, the enormity of the observed eddies could impact the rate at which the ocean draws down head and carbon. Eddies are not considered when climate predictions about global warming are made, as they are small in relation and practically remain ‘invisible’ in future climate-current models. Their impact on climate projection is underestimated and should be brought to light.
Oceanic eddies, Oceanic mesoscale eddies, global warming, climate prediction, climate change.