Nearly all marine species threatened by climate change: Study

On the current trajectory of global greenhouse gas emissions, nearly all marine species will be at high or critical risk of extinction in less than 80 years, according to a study published Monday by Nature Climate Change.

The study, which was conducted by an international team of researchers, looked at the effects of rising air and water temperatures due to the burning of fossil fuels on the marine animals, plants, protozoans and bacteria found in the upper 100 meters of the world's oceans. In that depth, the study noted, "climate-driven temperature changes are the most severe."

If the world was to continue on its current rate of greenhouse gas emissions, "almost 90% of ~25,000 species are at high or critical risk of extinction," the study concluded.

Mitigating the effects of climate change "reduces the risk for virtually all species," the study found. The findings come as the U.S. enacts the Inflation Reduction Act, the first major piece of legislation designed to curb greenhouse gas emissions and speed the transition to renewable sources of energy.

The study ranked the species most vulnerable to climate change, and determined that the Chinese puffer fish (Takifugu chinensis) and the Galapagos damselfish (Asurina eupalama) were the two species at greatest risk of extinction.

While climate change has been wreaking havoc in recent years in the form of extreme weather, drought and rising surface temperatures that have forced human beings to begin looking for ways to adapt, the brunt of the excess warming caused by the greenhouse effect has fallen on the world's oceans.

A scuba is seen in silhouette, surrounded by many, many fish.
A scuba diver swims in the middle of a school of jet fish at a diving site near Borneo. (Peter Andrews/Reuters)

Data from the National Oceanic and Atmospheric Administration has shown that "the ocean absorbs more than 90 percent of the excess heat" attributed to emissions.

Numerous studies have linked rising levels of carbon dioxide in the atmosphere with ocean acidification that impacts marine life.

"Although the ocean’s ability to take up carbon dioxide prevents atmospheric levels from climbing even higher, rising levels of carbon dioxide dissolved in the ocean can have a negative effect on some marine life. Carbon dioxide reacts with sea water to produce carbonic acid," the Environmental Protection Agency says on its website. "The resulting increase in acidity (measured by lower pH values) changes the balance of minerals in the water. This makes it more difficult for corals, some types of plankton, and other creatures to produce a mineral called calcium carbonate, which is the main ingredient in their hard skeletons or shells."

Without significant mitigation efforts, climate change is poised to impact global fisheries and will be felt hardest in poorer countries that rely on ocean sea life as a source of food.

"There was a really striking pattern where the risk was systematically higher for nations that have a lower socioeconomic status, lower income nations that tend to be more dependent on fisheries and tend to have a lower food security, and overall nutritional status," Daniel Boyce, an ecologist at the Bedford Institute of Oceanography in Nova Scotia and author published in Nature Climate Change, told ABC News.