How nuclear war may harm ocean life decoded

A nuclear conflict could worsen the impact of ocean acidification on corals, oysters and other shelled marine animals, according to a study which simulated a range of hypothetical wars, including one between India and Pakistan.

The study, published in the journal Geophysical Research Letters, looked at how climate changes stemming from nuclear war would affect the oceans.

"We found that the ocean's chemistry would change, with global cooling dissolving atmospheric carbon into the upper ocean and exacerbating the primary threat of ocean acidification," said Alan Robock, a professor at Rutgers University in the US.

The researchers used a global climate model in which the climate reacted to black carbon in smoke that would be injected into the upper atmosphere from fires ignited by nuclear weapons.

They considered a range of hypothetical nuclear wars, including a relatively small one between India and Pakistan and a large one between the US and Russia.

Excess carbon dioxide from the burning of fossil fuels enters the ocean and reacts with water to form carbonic acid, which makes the ocean more acidic, and lowers levels of carbonate ions, the researchers noted.

They said corals, clams, oysters and other marine organisms use carbonate ions to create their shells and skeletons, according to the National Oceanic and Atmospheric Administration.

A more acidic ocean, the researchers explained, makes it harder to form and maintain shells and skeletons.

The massive amount of smoke from a nuclear conflict would block sunlight and cause global cooling, which would temporarily boost the pH in the surface ocean over five years, and briefly lessen the acidification, they said.

However, the cooling would also lead to lower levels of carbonate ions for about 10 years, challenging shell maintenance in marine organisms, according to the researchers.

"We have known for a while that agriculture on land would be severely affected by climate change from nuclear war," Robock said.

"A lingering question is whether the survivors could still get food from the sea. Our study is the first step in answering this question," he said.