LLNL scientists to present global warming mitigation tool for ridding the atmosphere of excess carbon

December 12, 2001

SAN FRANCISCO, Calif.--Researchers from the Lawrence Livermore National Laboratory today will present evidence that a new method for capturing carbon dioxide from power plants and placing it in the ocean has less impact on marine life than atmospheric carbon dioxide release or other global warming mitigation methods, such as direct injection and ocean fertilization.

LLNL earth scientists Greg Rau, Ken Caldeira and Kevin Knauss will showcase the research, called carbonate dissolution, today at the 2001 Fall Meeting of the American Geophysical Union in San Francisco. The proposal would hydrate the carbon dioxide in power plant flue gas with water to produce a carbonic acid solution. This solution would be mixed with limestone ---- that neutralizes the carbon dioxide by converting it to bicarbonate -- and then would be released in the ocean. This process occurs naturally (carbonate weathering), but at a much slower pace.

"You are altering the chemistry of the carbon dioxide that causes a less drastic change to ocean pH (acidity) and is less biologically harmful than other methods such as direct injection ocean carbon sequestration and ocean fertilization," said Rau, an LLNL guest scientist who also works as a senior researcher with the Institute for Marine Sciences at the University of California, Santa Cruz.

Whether carbon dioxide is released in the atmosphere or the ocean, eventually about 80 percent of the carbon dioxide will end up in the ocean in a form that will make the ocean more acidic. While the carbon dioxide is in the atmosphere, it could produce adverse climate change. When it enters the ocean, the acidification could be harmful to marine life.

"If the carbon dioxide were reacted with crushed limestone and seawater, and the resulting solution released to the ocean, the limestone would buffer the pH (acidity) of the ocean and prevent it from becoming more acidic," Caldeira said. "Furthermore, the dissolved limestone would tend to keep the carbon dioxide in the ocean and out of the atmosphere. This process would occur naturally anyway, but on about a 6000-year time scale."

LLNL scientists are now engaged in both experimental and modeling work to study the feasibility of the proposed method of ocean carbon sequestration. Caldeira said initial results appear promising. Researchers believe that the carbonate dissolution process would expand the capacity of the ocean to store carbon dioxide while minimizing the amount of carbon going back into the atmosphere, unlike some of the other forms of carbon dioxide sequestration.

Direct injection of carbon dioxide into the deep ocean will likely negatively impact marine organisms and their ecosystems, due to the increased acidity. Recent research shows that the acid-base imbalance can cause exoskeletal components to decay, retard growth and reproduction, reduce activity and cause loss of consciousness and even death to deep ocean marine life because of a disruption of oxygen-transport mechanisms (Science, Vol. 294, p. 319-320).

In addition, Caldeira, in previous studies, showed that unless carbon dioxide is converted to some other form before injection, it will degas back to the atmosphere when diffusion or ocean circulation returns it to the ocean surface. In ocean fertilization, the biology of phytoplankton (which grows close to the ocean surface) is changed so that it increases the conversion of carbon dioxide to biomass. The conversion is likely to transport acidity from the surface ocean to the deep ocean.

Rau said private companies operating power plants would need incentives to start a carbonate dissolution program. "They need motivation to sequester carbon dioxide, and they need methods that are effective and are economically and environmentally practical," he said. "Carbonate dissolution allows a power plant to continue burning fossil fuel but eliminate at least some of the carbon dioxide that is emitted, and in a way that is probably less expensive and more environmentally friendly than other carbon dioxide sequestration methods."

LLNL researchers will present their findings today and will be available to the press and public at 10 a.m. during a press conference titled "Global Warming Mitigation."
Founded in 1952, Lawrence Livermore National Laboratory is a national security laboratory, with a mission to ensure national security and apply science and technology to the important issues of our time. Lawrence Livermore National Laboratory is managed by the University of California for the U.S. Department of Energy's National Nuclear Security Administration.

DOE/Lawrence Livermore National Laboratory

Related Atmosphere Articles from Brightsurf:

ALMA shows volcanic impact on Io's atmosphere
New radio images from ALMA show for the first time the direct effect of volcanic activity on the atmosphere of Jupiter's moon Io.

New study detects ringing of the global atmosphere
A ringing bell vibrates simultaneously at a low-pitched fundamental tone and at many higher-pitched overtones, producing a pleasant musical sound. A recent study, just published in the Journal of the Atmospheric Sciences by scientists at Kyoto University and the University of Hawai'i at Mānoa, shows that the Earth's entire atmosphere vibrates in an analogous manner, in a striking confirmation of theories developed by physicists over the last two centuries.

Estuaries are warming at twice the rate of oceans and atmosphere
A 12-year study of 166 estuaries in south-east Australia shows that the waters of lakes, creeks, rivers and lagoons increased 2.16 degrees in temperature and increased acidity.

What makes Saturn's atmosphere so hot
New analysis of data from NASA's Cassini spacecraft found that electric currents, triggered by interactions between solar winds and charged particles from Saturn's moons, spark the auroras and heat the planet's upper atmosphere.

Galactic cosmic rays affect Titan's atmosphere
Planetary scientists using the Atacama Large Millimeter/submillimeter Array (ALMA) revealed the secrets of the atmosphere of Titan, the largest moon of Saturn.

Physics: An ultrafast glimpse of the photochemistry of the atmosphere
Researchers at Ludwig-Maximilians-Universitaet (LMU) in Munich have explored the initial consequences of the interaction of light with molecules on the surface of nanoscopic aerosols.

Using lasers to visualize molecular mysteries in our atmosphere
Molecular interactions between gases and liquids underpin much of our lives, but difficulties in measuring gas-liquid collisions have so far prevented the fundamental exploration of these processes.

The atmosphere of a new ultra hot Jupiter is analyzed
The combination of observations made with the CARMENES spectrograph on the 3.5m telescope at Calar Alto Observatory (Almería), and the HARPS-N spectrograph on the National Galileo Telescope (TNG) at the Roque de los Muchachos Observatory (Garafía, La Palma) has enabled a team from the Instituto de Astrofísica de Canarias (IAC) and from the University of La Laguna (ULL) to reveal new details about this extrasolar planet, which has a surface temperature of around 2000 K.

An exoplanet loses its atmosphere in the form of a tail
A new study, led by scientists from the Instituto de Astrofísica de Canarias (IAC), reveals that the giant exoplanet WASP-69b carries a comet-like tail made up of helium particles escaping from its gravitational field propelled by the ultraviolet radiation of its star.

Iron and titanium in the atmosphere of an exoplanet
Exoplanets can orbit close to their host star. When the host star is much hotter than our sun, then the exoplanet becomes as hot as a star.

Read More: Atmosphere News and Atmosphere Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.