The planet's oceans are almost too acidic to sustain marine life.
A report by the Potsdam Institute for Climate Impact Research (PIK) says that ocean acidification could be the latest threshold to be breached in terms of Earth's ability to support life.
The experts have warned that the safe limit has been exceeded in six of the nine pivotal factors due to human activity.
Sustainable levels of acid in the oceans now appear set to be surpassed due to continued emissions of carbon dioxide (CO2).
Boris Sakschewski, one of the lead authors of the report, said: "As CO2 emissions increase, more of it dissolves in seawater... making the oceans more acidic.
"Even with rapid emission cuts, some level of continued acidification may be unavoidable due to the CO2 already emitted and the time it takes for the ocean system to respond.
"Therefore, breaching the ocean acidification boundary appears inevitable within the coming years."