Effects of carbon dioxide and climate change on ocean acidification and carbonate mineral saturation

Long Cao, Ken Caldeira, Atul K. Jain

Research output: Contribution to journalArticlepeer-review


We use an earth system model of intermediate complexity to show how consideration of climate change affects predicted changes in ocean pH and calcium carbonate saturation state. Our results indicate that consideration of climate change produces second-order modifications to ocean chemistry predictions made with constant climate; these modifications occur primarily as a result of changes in sea surface temperature, and climate-induced changes in dissolved inorganic carbon concentrations. Under a CO2 emission scenario derived from the WRE1000 CO2 stabilization concentration pathway and a constant climate, we predict a 0.47 unit reduction in surface ocean pH relative to a pre-industrial value of 8.17, and a reduction in the degree of saturation with respect to aragonite from a pre-industrial value of 3.34 to 1.39 by year 2500. With the same CO2 emissions but the consideration of climate change under a climate sensitivity of 2.5°C the reduction in projected global mean surface pH is about 0.48 and the saturation state of aragonite decreases to 1.50. With a climate sensitivity of 4.5°C, these values are 0.51 and 1.62, respectively. Our study therefore suggests that future changes in ocean acidification caused by emissions of CO2 to the atmosphere are largely independent of the amounts of climate change.

Original languageEnglish (US)
Article numberL05607
JournalGeophysical Research Letters
Issue number5
StatePublished - Mar 16 2007

ASJC Scopus subject areas

  • Geophysics
  • General Earth and Planetary Sciences


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