Polar bears on a block of melting ice in the Arctic (CUNY.edu)

Researchers from the Polar and Marine Research Institute at Jimei University in China and the School of Marine Science and Policy at the University of Delaware in the US have discovered that acidification of the western Arctic Ocean is occurring three to four times faster than in other ocean basins - causing a large and rapid loss of the sea ice in the region over the past three decades.

Due to the increased use of fossil fuels, the ocean, which is responsible for absorbing a third of CO2 in the atmosphere, has witnessed a staggering level of acidity, leading the seawater to be exposed to the atmosphere and thus a faster rate of carbon dioxide takeup.

Wei-Jun Cai, one of the authors of the study and a marine chemistry expert at the University of Delaware, stated that “in other ocean systems, acidification is being driven by an increase in atmospheric carbon dioxide, which is increasing at a rate of around 2ppm [parts per million] per year."

The process could even escalate in the upcoming decades if ice in the sea continues to melt in the Arctic. “The ice melt dilutes or lowers the alkalinity of the seawater. This dilutes the buffering capacity of the water, its ability to resist acidification,” Cai said.

The research comes after a separate study was released in August, regarding the warming of the Arctic, found to have happened at about four times the global average rate over the past 43 years in a process called Arctic amplification, which comprises a feedback process fueled by melting sea ice, just like the rapid acidification taking place. When data collected from the Arctic between 1994 and 2020 was compared by the researchers with other ocean basins, they deduced that the Arctic was witnessing the fastest rate of acidification.

Cai refers to previous research that demonstrates the threat ocean acidification poses to coral reefs as an example of the 'huge implications' created by altered seawater chemistry, adding, “In lower latitudes, you have coral reefs and if you add carbon dioxide to the water, the carbon saturation rate will increase and the coral won’t grow,” such that acidification reduces the carbonate ions required to build coral skeletons.

Earlier this month, a study by the World Meteorological Organization showed that the world's oceans absorb more than 90% of the heat trapped by greenhouse gases, tying ocean warming to extreme weather and climate events, as the global average sea level rose to a record high for the 10th consecutive year.

Lower PH levels of seawater could potentially and eventually affect other systems and make some metals more toxic, according to Cai, who also commented, “We are far from knowing what the cost is for biological systems. We don’t know what organisms could be affected. This is something the biological community needs to look into.”

Scientists have revealed that some parts of the Mediterranean are this year more than 6°C warmer than usual in comparison with previous years, which sparks fears that the sea's fragile ecosystems are suffering what can be called a "marine wildfire" and being changed forever by global warming.