The study, recently published in the journal Progress in Oceanography, analyzes in particular southeast and southwest Alaska. Because of these regions’ relatively low incomes and scarcity of employment alternatives, ocean acidification poses the greatest threat to the livelihoods of its fishermen. Alaska’s economy is highly dependent on its fishing grounds, which are among the most fertile in the world.
According to the study, the Earth’s atmospheric carbon dioxide concentration has increased by about 40 percent in the last 250 years, primarily driven by the burning of fossil fuels. CO2 levels are now at 400 parts per million, which is the highest concentration recorded in the last 800,000 years of the planet’s history. The ocean absorbs over 25 percent of this carbon dioxide, which causes a chemical reaction that reduces the level of calcium carbonate minerals in the water – the key ingredient in the formation of several marine species’ shells.
Ocean acidification is already affecting shellfish species along the west coast of the United States. In Washington state, oyster production has declined by about 42 percent, with whole populations of oysters too weak to survive. This puts the state’s whole economy in jeopardy, according to Jay Inslee, Washington’s governor. “You can’t overstate what this means to Washington,” he says.
The NOAA study calculates that oceans are 30 percent more acidic than before the Industrial Revolution, and this is causing harm to Alaska’s pteropods, tiny shellfish that constitute the main diet of the state’s salmon stocks. Alaskan waters are particularly vulnerable to acidification due to their geographic position.
“It’s all about geography,” says Jeremy Mathis, NOAA oceanographer and lead author of the study. “The world’s ocean currents end their cycles here, depositing carbon dioxide from elsewhere. The coastal waters of Alaska sit right at the end of the ocean conveyor belt.”
If the populations of Alaskan crabs and salmon decrease, it will affect not only the state’s commercial fishing sector but also its fishermen, who often subsist on what they catch.
“This is an economic-social study,” Mathis told the Alaska Dispatch News. “It focuses on food security, employment opportunity, and the size of the economy.”
The study notes that its findings are merely an intermediate step toward greater analysis and policy planning for Alaska’s future.