Ocean Acidity

Gases emitted into the atmosphere are inevitably absorbed by our oceans. Much of the CO2 already emitted has gone into the oceans and ocean acidity has been measured to be increasing (historically around 8.17 pH).

The implications are that by the end of the century creatures who create carbonate shells (including corals) may be gone as they will be unable to form Calcium Carbonate from the ocean waters anywhere throughout the ocean. The collapse of the shell fish (e.g. plankton) and the coral reef system will seriously impact on biodiversity with the consequent disruption to food sources from the ocean on which human society depends.

Widespread coral bleaching events during 2014 to 2017 (which damaged 70% of the worlds reefs) are totally unprecedented and portend the rapid loss of corals around the world. We are also seeing recent loss of large scale habitats such as kelp forests. 

Impact type                       2050                             2100                          2300
.                                      Low        High                Low        High             Low        High

Decreased pH                 8.0        7.9                  7.8         7.7

% Loss of carbonate
forming species              10          30                  70          90

% Loss of foraminifera
and plankton                  10           30                 60          85

 [Reviewed Feb 2019]