Ocean acidification

When acidification became an alarming issue in the1970s it was mainly lakes and to a certain extent forests that were threatened by increased levels of hydrogen ions (decreasing pH) as a result of emissions of sulphuric and nitric oxides from industry and transports. Acidification of lakes and forests is still a problem in parts of the world, but the problem is regional and can be mitigated through spreading of chalk and is hence not regarded as an important issue as compared to the new acidification trend: ocean acidification. The mechanism behind ocean acidification is completely different from that behind inland acidification; it is caused by increasing levels of carbon dioxide in the atmosphere. When carbon dioxide is dissolved in water the pH decreases. The present rate of ocean acidification is at least 100 times faster than at any other time in the last 20 million years (Rockström et al. 2009). If CO2 emissions continue to rise, and the acidity of the world’s oceans continues to increase at this rate, this could have serious consequences for marine life (e.g. corals, shellfish, algae and the plankton that form the base of the food chain) within this century.


Rockström, J., W. Steffen, et al. (2009). “A safe operating space for humanity.” Nature 461(7263): 472-475.

Rockström, J., W. Steffen, et al. (2009). “Planetary boundaries: Exploring the safe operating space for humanity.” Ecology and Society 14(2): 32.