[Sust-mar] Ocean acidification

[Christopher Majka]

Greetings,

Since the beginning of the industrial revolution some 250 years ago,  
human civilization has been burning fossil fuels at an accelerating  
rate. The carbon dioxide emitted is a powerful greenhouse gas. The  
focus of much concern by environmentalists has been on the role of  
carbon dioxide in causing climate change. However, all the carbon  
dioxide that is emitted initially goes into the atmosphere, and since  
71% of the earth's surface is covered by oceans, much of that -  
currently some 6 million tons of carbon dioxide per day - dissolves  
into the water, creating carbonic acid.

The oceans have absorbed roughly 30% of the carbon dioxide caused by  
the burning of fossil fuels, and they contain vast reservoirs of  
dissolved carbon dioxide. Although as a percentage, the increase has  
been very small, about 3% in surface waters and 0.25% in the ocean  
overall, the effect has been quite large. Ocean acidity has increased  
by 30% since pre-industrial levels (from pH 8.25 to 8.14) and modeling  
shows that if we continue to emit carbon dioxide at the current rate  
ocean acidity will double (roughly to pH 7.9) by the end of the 21st  
century. This would be the largest change in the acidity of oceans to  
occur in many tens of millions of years.

If this happens, a myriad of animals and plants in the ocean --  
mollusks (mussels, scallops, oysters, clams, snails), barnacles, sea  
urchins, starfish, crinoids, corals, coralline algae, foraminifera,  
and coccolithophores -- may simply dissolve into oblivion.

Those interested in this topic are invited to peruse my recent article  
for Rabble.ca entitled:

	Acid bath: Evil twin of climate change
	http://rabble.ca/blogs/bloggers/christophermajka/2012/06/acid-bath-evil-twin-climate-change

Best wishes,

Chris


Christopher Majka
Halifax, Nova Scotia, Canada
c.majka at ns.sympatico.ca

The good thing about science is that it's true whether or not you  
believe in it - Neil deGrasse Tyson