| Exceeding critical thresholds Stelling1 #145943 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.
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