WASHINGTON — A sobering new report warns that the oceans face a «fundamental and
irreversible ecological transformation» not seen in millions of years as greenhouse gases and climate
change already have affected temperature, acidity, sea and oxygen levels, the food chain and
possibly major currents that could alter global weather.
The Planetary Boundaries framework proposes quantitative limits for human perturbation of critical Earth system processes, and a «safe operating space» within which human activity should attempt to stay in order to avert the risk of large - scale,
possibly abrupt or
irreversible environmental
change.