Make oceans vast carbon sinks, U.S. researchers say

Speeding up anatural process through "electrochemical weathering" couldbe used toabsorb carbon in oceans and reducethe impact of climate change, U.S. researchers say.

"Our technology dramatically accelerates a cleaning process that Nature herself uses for greenhouse gas accumulation," Harvard University PhD candidate Kurt Zenz House said in a release Thursday.

Thescheme isambitious, costly and has its own risks,the researchers said.It would require building dozens of facilities on coasts of volcanic rock.

Oceans have absorbed about one-third of thecarbon dioxide that humans have produced, but the process is very slow,the journal Environmental Science and Technology said on its website. And the more acidic oceans are, the less CO2 they can absorb.

House and colleagues from Harvard and Pennsylvania State University said they found a way toremove hydrochloric acid from the ocean andneutralize it using silicate from volcanic rocks. Thatincreases the ocean's alkalinity, soitcanstore more atmospheric CO2 asbicarbonate, already the mostcommon form of carbon in the oceans.

"That means we may be able to safely and permanently remove excess CO2 in a matter of decades rather than millennia," House said, describing the process as accelerating the natural system to industrial rates.

In nature, carbon dioxide is dissolved by fresh water, forming a weak acid. Theacid is neutralized as water filters through rocks, producing an alkaline solution of carbonate salts, the release said.

Eventually the water reaches an ocean, where thealkaline solution holds the dissolved carbon until it eventually becomes a sediment.

The researchers' process uses other chemical processes to minimize potential side effects.

There are other plans tosequester carbon in oceans, but this proposal reduces acidity.

House andcolleague Harvard professor Michael J. Aziz said moreresearch is needed on the process.

As well asHouse and Aziz, the researchers include House's brother Christopher H. House, associate professor at Pennsylvania State University andDaniel P. Schrag, director of the Harvard University Center for the Environment.

Environmental Science and Technology published the research.