Exceeding critical thresholds
Declines in biodiversity and ecosystem services tend to be unexpected, abrupt collapses that are more likely to occur once a tipping point has been passed.
  • Examples of such ‘regime shifts’ include bush encroachment and desertification in Africa, coral bleaching in Asia and salinized rangelands in Australia. Furthermore, coastal areas worldwide are becoming affected by excessive nutrient loads originating most frequently from agriculture, sewage and industrial waste.
  • These cause vast algal blooms and create oxygen-depleted zones where fish and other marine organisms can no longer survive. Future risks include forest dieback in the Amazon basin and widespread collapse of coral reefs because of ocean acidification. Reversing changes like these is at best, very slow and expensive and at worst, impossible. There is an urgent need to act now before such thresholds are reached.

Planet Under Pressure »Planet Under Pressure
4. The way ahead »4. The way ahead
Policy Briefs »Policy Briefs
4. Biodiversity and ecosystems »4. Biodiversity and ecosystems
Biodiversity and Ecosystem Concerns »Biodiversity and Ecosystem Concerns
Exceeding critical thresholds
Coral reef destruction »Coral reef destruction
Ocean Acidification »Ocean Acidification
Ocean De-oxygenation »Ocean De-oxygenation
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