France, Sept. 27 -- With oceans showing dangerous levels of acidity, seven of nine crucial planetary boundaries - the limits beyond which Earth risks becoming uninhabitable for humans - have now been breached, climate researchers warn. But one of the authors of a new report tells RFI thathumanity still has a chance to reverse the trend.

The world's oceans have reached critical levels of acidity,the Potsdam Institute for Climate Impact Research (PIK) said in its annual Planetary Health Check, published this week.

It is the first time ocean acidity has crossed into the danger zone, the report warns, and latest red flag for Earth's health.

The institute measures the state of the planet's well-being by nine key thresholds, or "planetary bo...