World's Oceans on Verge of Being Too Acidic to Sustain Life, Scientists Warn ScienceAlertEarth may have breached seven of nine planetary boundaries, health check shows The GuardianSix Of Nine Earth Planetary Health Boundaries Have Been Broken – And There's More To Come IFLScienceWorld's oceans near critical acidification level: Report Phys.orgEarth exceeds safe limits: First Planetary Health Check issues red alert Virgin