Satellites reveal ocean currents are getting stronger, with potentially significant implications for climate change

This article was first published by The Conversation. Space.com's Expert voices: Op-Ed and Insights was contributed by the publication.Navid Constantinou Research Fellow, Australian National UniversityAdele Morrison is a Research Fellow at the Australian National UniversityAndrew Kiss, Research Fellow, Australian National UniversityAndy Hogg, Professor at the Australian National UniversityJosu Martnez Moreno, P.h.D. Candidat, Australian National UniversityMatthew England, Australian Research Council Laureate Fellow, Deputy Director of Climate Change Research Centre, (CCRC); Chief Investigator in ARC Centre of Excellence in Climate System Science at UNSWScientists know that the oceans are warming rapidly and that sea levels are rising. However, this is not all. We now have data from satellite observations that spans three decades on the speed of ocean surface currents.Our research, published in Nature Climate Change in April, details our findings about how ocean currents have become stronger over large areas of the ocean.What are ocean eddies and how do they work?You would be able to see the circular motions of the water in the ocean if you looked at it from a bird’s eye. These are known as "ocean-eddies". These features give the ocean an artistic taste, similar to Van Gogh’s Starry Night.Eddies can span anywhere from 10 to 100 kilometers in length. They can be found throughout the oceans. However, eddies are more abundant in certain regions.These include the Gulf Stream, Kuroshio Current, North Pacific, and Southern Oceans which surround Antarctica. Also, there is the East Australian Current, famously portrayed in "Finding Nemo".Ocean eddies play an important role in ocean circulation. They transport warm and cool water from one place to another. They combine heat, carbon, salt, and nutrients and can affect ocean conditions globally and regionally.Continue reading: The Southern Ocean is an ocean unlike any other: Its ecological richness, significance and importance for global climateSatellites continuously monitor the oceanSatellites orbiting Earth are equipped with powerful, specialized satellites that can monitor the movement of the ocean's surface. These satellites orbit thousands of kilometers above Earth, but they can detect changes of just a few centimeters in sea elevation.Through data analysis, we can then translate the sea surface elevation change into ocean flow speeds. This will tell us how energetic an ocean eddy really is.Our team was able to identify clear changes in ocean eddies' strength and distribution by carefully analysing satellite images. These changes were not previously seen.What a shift in the eddies!We used data available from 1993 to 2020 to analyze changes in the strength and distribution of eddies around the world. The results showed that regions already rich in eddies were becoming even more prosperous. Eddies are getting up to 5% more active each decade, on average.The Southern Ocean was one of the areas that showed the most significant changes. Eddy activity detected a huge 5% increase in the region every decade. The Southern Ocean is a hotspot of ocean heat uptake, carbon storage and carbon storage.Scientists could not observe ocean eddy changes until recently using only sparse ocean measurements and the limited satellite records. Experts are now able to draw solid conclusions from the satellite record about likely trends in eddy behavior over time.What is the point?Ocean eddies play an important role in climate change by controlling the transport and mixing of heat, carbon and biota in the oceans. Our research could have profound implications for the future climate.For decades, scientists have known that the Southern Ocean's eddies can cause the ocean to turn. Eddies can cause changes in the ocean's ability to draw down heat and carbon.However, eddies are not often considered in climate predictions for a warmer world. Because they are so small, they are virtually invisible in climate models that project the future.Eddy impacts are therefore not being considered in climate projections or underestimated. This is especially concerning given that we have discovered that eddies are getting more energetic.Our research demonstrates how important it is to include ocean eddies in future climate projections. We could overlook a crucial detail if we don't.Continue reading: An alien invasion of seaweed has created an Antarctic mysteryThis article was republished by The Conversation under Creative Commons. You can read the original article.Follow Expert Voices to keep up with the debates and issues. You can also join the conversation on Facebook and Twitter. These views are the author's and may not reflect those of the publisher.