Fix acid oceans by dumping alkali in them? Forget it

Suggestions that we can dump large amounts of alkaline chemicals into the oceans to prevent their acidification seems dead in the water. A study shows it would cost trillions of dollars.

As humans spew more carbon dioxide into the atmosphere, it is taken up by the oceans, turning them increasingly acidic and threatening ecosystems around the globe.

Some have suggested a simple solution: large-scale artificial alkalisation using chemicals like quicklime. Richard Zeebe and Fran?ois Paquay of the University of Hawaii in Honolulu decided to see if this was realistic.

Three-ocean problem

For this, they used a model of how carbon cycles between the atmosphere, ocean and sediment. "We envisioned this as an extremely large-scale problem," says Paquay, "so we manipulated the alkalinity in the surface of the Atlantic, Pacific and Indian oceans."

His team modelled the coming 500 years assuming we continue emitting greenhouse gases at roughly the same rate as we have on average over the past century. They found to counteract ocean acidification, we would have to dump about 10¹⁵ moles per year of alkalinity into the oceans for about 400 years. If quicklime were to be used, it would require approximately 1000 tons and trillions of dollars per year.

What's more, geoengineering the oceans in this way would not do anything to stop global temperatures rising ? in the models, Earth's temperature rose by about 2.5??C.

Ocean alkalisation is unlikely to be an economically viable geoengineering option to offset global carbon emissions, the researchers concluded in a presentation at the fall meeting of the American Geophysical Union in San Francisco, California, last week.

If you would like to reuse any content from New Scientist, either in print or online, please contact the syndication department first for permission. New Scientist does not own rights to photos, but there are a variety of licensing options available for use of articles and graphics we own the copyright to.

Have your say

Only subscribers may leave comments on this article. Please log in.

Only personal subscribers may leave comments on this article

Subscribe now to comment.

All comments should respect the New Scientist House Rules. If you think a particular comment breaks these rules then please use the "Report" link in that comment to report it to us.

If you are having a technical problem posting a comment, please contact technical support.

Source: http://feeds.newscientist.com/c/749/f/10897/s/1afcdb65/l/0L0Snewscientist0N0Carticle0Cdn212940Efix0Eacid0Eoceans0Eby0Edumping0Ealkali0Ein0Ethem0Eforget0Eit0Bhtml0DDCMP0FOTC0Erss0Gnsref0Fonline0Enews/story01.htm

dragonfly courtney stodden drake take care herman cain accuser herman cain accuser election day kawasaki disease