The theory is that by analyzing the amounts of C-14 vs C-12 they can “date” the age of the carbon, the older the source carbon before combustion, the more likely it came from fossil fuels which is what we burn in the industrial engine and our motorboats, cars etc.
This only works for the absorbed CO2 from the atmosphere, not from underwater contributions.
Since the release clearly states that nothing we do at this point will reverse any near-future damage because the tiny amounts being absorbed daily will take hundreds of years to cycle through the air-sea transport the authors offer no mitigation schemes nor do they address this study’s effect on climate models.
It’s too bad that a respected journal such as Science has signed on to the press-release marketing syndrome.