At the Scripps Institution of Oceanography at UC San Diego, an international research group made use of computer model simulations to determine that climate change is changing the mechanics of surface ocean circulations, thereby making them thinner and faster.
Image Credit: NASA.
Such alterations can result in a ripple effect in the ocean, causing an impact on the transport of the nutrients organisms’ requirements as well as that of microorganisms themselves. Also, swifter currents might impact the processes by which the ocean eliminates carbon and heat from the air and safeguards the planet from too much atmospheric warming.
We were surprised to see that surface currents speed up in more than three-fourths of the world’s oceans when we heated the ocean surface.
Qihua Peng, Study Lead Author, State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences
Recently, Peng united with Scripps Oceanography as a postdoctoral researcher.
The study provides better insights into underestimated force behind the speed of global ocean currents. Hence, it aids in resolving a debate on whether currents are expediting due to global warming.
The study was reported in the Science Advances journal on April 20th, 2022.
The primary factor that was studied by the researchers was wind, which turned out to be useful when it came to explaining and forecasting the speed of currents. However, the research group utilized a global ocean model to simulate what occurs when there is an increase in sea surface temperatures.
The researchers discovered that warming makes the topmost layers of water become lighter. The growing density difference that causes the warming of surface layers from the cold water below restricts the swift ocean currents to a thinner layer. This causes the surface currents to expedite in over three-fourths of the world’s oceans.
The growing speed of rotating ocean currents, called gyres, was linked with a deceleration of ocean circulation below. The team made a direct correlation between the trend and the existence of highly increased levels of greenhouse gases present in the air.
Our study points to a way forward for investigating ocean circulation change and evaluating the uncertainty.
Shang-Ping Xie, Climate Modeler Scripps Oceanography, Scripps Institution of Oceanography, University of California San Diego
The portion of the work done by Xie has been financially supported by the National Science Foundation.
In the majority of the oceans bounded by continents, currents are arranged into gyres. The Southern Ocean that surrounds Antarctica is considered an exclusion. There, howling westerly winds tend to make the Antarctic Circumpolar Current the biggest in the world relating to volume transport.
In 2021, researchers from Scripps detected from ocean and space observations that the Antarctic Circumpolar Current is expediting.
The accelerating Antarctic Circumpolar Current is exactly what our model predicts as climate warms.
Shang-Ping Xie, Climate Modeler Scripps Oceanography, Scripps Institution of Oceanography, University of California San Diego
The co-authors of the study include Dongxiao Wang of Sun Yat-Sen University in China, and also researchers from the Chinese Academy of Sciences, Woods Hole Oceanographic Institution in Massachusetts, and UC Riverside.
Journal Reference:
Peng, Q., et al. (2022) Surface warming–induced global acceleration of upper ocean currents. Science Advances. doi.org/10.1126/sciadv.abj8394.