BERLIN, Sept 13 (Reuters) - The Earth's life-support systems are facing greater risks and uncertainties than ever before, with most major safety limits already crossed as a result of planet-wide human interventions, according to a scientific study released on Wednesday. The authors said crossing the boundaries did not represent a tipping point where human civilisation would just crash, but could bring irreversible shifts in the Earth's support systems. "We can think of Earth as a human body, and the planetary boundaries as blood pressure. Over 120/80 does not indicate a certain heart attack but it does raise the risk," Richardson said. "It is a complete failure ...and it's a large risk... We're still following a pathway that takes us unequivocally to disaster."

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Persons: Katherine Richardson, Richardson, Ueslei Marcelino, We're, Johan Rockström, I've, Rockström, Riham, David Stanway, Mark Heinrich Our Organizations: University of Copenhagen, REUTERS, Potsdam Institute, Climate Impact, United Nations Global, Thomson Locations: Seca, Uruara, Para State, Brazil, Dubai