Past studies have found that the ocean temperature is rising rapidly, but a study that simulates the entire Earth’s currents based on vast observational data also revealed that the Earth’s ocean currents are accelerating.
The research team of Qingdao Ocean Research Institute of the Chinese Academy of Sciences discovered that the currents are accelerating globally. Research so far has confirmed that global warming is affecting ocean currents in many areas, but the global trend has not been clear. The research team received observation records from the ARGO plan, which collects data such as sea temperature, salinity, and flow velocity up to a depth of 2,000 m by floating 4,000 observation floats around the world. In addition, the changes in ocean currents since 1990 have been investigated by combining 5 observation data and 12 simulations conducted by research institutes around the world so far.
As a result, it was confirmed that from 1990 to 2013, the kinetic energy of ocean currents increased by 15% every 10 years. It is said that this increase in kinetic energy amounts to 76% of the world’s oceans.
The research team believes that the direct cause of the accelerating ocean current is the increase in wind speeds brought about by global warming. First of all, global warming was viewed as slowing the wind movement. This is because the temperature in polar regions such as the North Pole is warmer than near the equator, so the temperature in the polar and equator regions will decrease and atmospheric movement will slow down. In fact, from 1970 to 2010, wind speeds are decreasing worldwide, and this phenomenon is called global terrestrial stilling. However, after 2010, on the contrary, it is confirmed that the wind speed is increasing, and this theory may be reversed.
The reason for the increase in wind speeds that have fallen over the past 40 years from 2010 is not clear, but the research team concluded that the increase in wind speeds was far greater than what can be explained by natural changes and that global warming was the main cause.
The research team believes that the current velocity is due to global warming, but at the same time pointed out that the current velocity also accelerates global warming. For example, when tropical currents accelerate, warm seawater is transferred to a wider area than before. The sea absorbs carbon dioxide, but carbon dioxide is difficult to dissolve in high-temperature water. Therefore, when the water temperature increases widely due to the acceleration of the ocean current, the amount of carbon dioxide absorbed by the sea decreases.
The research team found that the Pacific Ocean’s Southern Equatorial Current is gentle enough to move about 1.6 km per hour, so even if it accelerates, it is about 0.08 km/h in 10 years. However, considering that the seawater is vast, it requires a lot of energy at just this acceleration. This level of energy is difficult to explain due to natural changes, and the cause is likely to be global warming. Related information can be found here .