https://en.wikipedia.org/wiki/Ocean_acidification
Ocean acidification is the ongoing decrease in the pH of the Earth's oceans, caused by the uptake of carbon dioxide (CO
2) from the atmosphere.[2] An estimated 30–40% of the carbon dioxide released by humans into the atmosphere dissolves into oceans, rivers and lakes.[3][4] To achieve chemical equilibrium, some of it reacts with the water to form carbonic acid. Some of these extra carbonic acid molecules react with a water molecule to give a bicarbonate ion and a hydronium ion, thus increasing ocean "acidity" (H+ ion concentration). Between 1751 and 1994 surface ocean pH is estimated to have decreased from approximately 8.25 to 8.14,[5]
representing an increase of almost 30% in H+ ion concentration in the world's oceans.[6][7] Earth System Models project that within the last decade ocean acidity exceeded historical analogs [8] and in combination with other ocean biogeochemical changes could undermine the functioning of marine ecosystems and many ocean goods and services.[9]
REFERENCES
1) "Feely et al. - Evidence for upwelling of corrosive "acidified" water onto the Continental Shel". pmel.noaa.gov. Retrieved 2014-01-25.
2) Caldeira, K.; Wickett, M. E. (2003). "Anthropogenic carbon and ocean pH". Nature 425 (6956): 365–365. Bibcode:2001AGUFMOS11C0385C. doi:10.1038/425365a. PMID 14508477.
3) Millero, Frank J. (1995). "Thermodynamics of the carbon dioxide system in the oceans". Geochimica et Cosmochimica Acta 59 (4): 661–677. Bibcode:1995GeCoA..59..661M. doi:10.1016/0016-7037(94)00354-O.
4) Feely, R. A.; et al. (July 2004). "Impact of Anthropogenic CO2 on the CaCO3 System in the Oceans". Science 305 (5682): 362–366. Bibcode:2004Sci...305..362F. doi:10.1126/science.1097329. PMID 15256664.
5) Jacobson, M. Z. (2005). "Studying ocean acidification with conservative, stable numerical schemes for nonequilibrium air-ocean exchange and ocean equilibrium chemistry". Journal of Geophysical Research – Atmospheres 110: D07302. Bibcode:2005JGRD..11007302J. doi:10.1029/2004JD005220.
6) Hall-Spencer, J. M.; Rodolfo-Metalpa, R.; Martin, S.; et al. (July 2008). "Volcanic carbon dioxide vents show ecosystem effects of ocean acidification". Nature 454 (7200): 96–9. Bibcode:2008Natur.454...96H. doi:10.1038/nature07051. PMID 18536730.
7) Report of the Ocean Acidification and Oxygen Working Group, International Council for Science's Scientific Committee on Ocean Research (SCOR) Biological Observatories Workshop
8) Mora, C (2013). "The projected timing of climate departure from recent variability". Nature 502: 183–187. doi:10.1038/nature12540.
9) Mora, C. et al. (2013). "Biotic and Human Vulnerability to Projected Changes in Ocean Biogeochemistry over the 21st Century". PLoS Biology 11: e1001682. doi:10.1371/journal.pbio.1001682.
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So, numbnuts, it took 30% more than was there in 1751.
and now, you stupid ass, tell us what you're going to DO with the number.