Not subscribed?

Pre-industrial conditions were recreated by lowering the ocean acidity levels to pH8.2 and decreasing the temperature by 1°C. In this sequence, you can see that only one species of coral is bleached. This species is known to be susceptible to thermal bleaching.

This time lapse shows the control conditions used for the experiment. Look for evidence of bleaching, i.e. the coral turning white, and coral mortality, when the coral dies and is overgrown with dark green algae. The ocean temperature varied over the seasons from 24.5°C to 28.5°C, with a pH of about 8.1.

This mesocosm has conditions based on what might happen by 2100 if global society worked to decrease emissions. Ocean acidification would still occur with pH levels falling from the current pH8.1 to pH7.9, and ocean temperatures are predicted to rise by 2°C. Compare how the coral fares under these conditions compared to pre-industrial and current levels.

Business as usual describes a scenario in which no additional efforts are made to curb emissions of carbon dioxide. Were this to happen, it is predicted that temperatures would rise 4°C by the end of the 21^st century, with ocean pH levels dropping to pH7.7. See how levels of coral bleaching and coral mortality compare to other scenarios.