Scientists Consider Permanent CO2 Storage in Deep-Sea Sediments

 

In the August 7 online issue of Proceedings of the National Academy of Sciences (PNAS), a study published by scientists at Harvard, MIT and Columbia universities finds that the first few hundred meters of deep-ocean sediments could provide permanent geologic storage of carbon dioxide (CO2). The plan involves pumping CO2 gas down to a depth of 3,000 meters (1.86 miles) and injecting it below the sea floor.

 

Dr. Daniel Schrag, director of Harvard's Center for the Environment, said "Supplying the energy demanded by world economic growth without affecting the Earth's climate is one of the most pressing technical and economic challenges of our time.... Since fossil fuels—particularly coal—are likely to remain the dominant energy source of the 21st century, stabilizing the concentration of atmospheric carbon dioxide will require permanent storage of enormous quantities of captured carbon dioxide safely away from the atmosphere."

 

At the high pressures and low temperatures common in deep-sea sediments, the CO2 would be liquid and denser than the water above it, keeping the injected CO2 trapped. Additionally, the CO2 would interact with surrounding sediments to create CO2 hydrate compounds that would serve as a second cap on the system. The study estimates the total CO2 storage capacity within the 200-mile economic zone of the U.S. coastline is capable of storing thousands of years of current U.S. CO2 emissions.

 

Click on the following links for the full news stories:  Harvard, BBC, New York Times and PNAS 

 

Antarctic Snowfall Unchanged, Climate Effects May be Delayed

 

A team of 16 researchers from nine institutions in seven countries finds that there has been no statistically significant change in snowfall in the Antarctic since the 1950s, indicating that Antarctic precipitation is not mitigating global sea level rise as expected, despite recent winter warming of the overlying atmosphere. The finding contradicts the predictions of most climate models that are based on the assumption that warming air can carry more moisture and produce greater snowfalls at the poles. This recent evidence supports the idea, not recognized in climate models, that there is a lag between global warming and Antarctica's response to it.

 

Australian team member and palaeoclimatologist Dr. Ian Goodwin, of the University of Newcastle, said "We can be relatively complacent about the effects of climate change in the Southern Hemisphere because we haven't seen dramatic changes.... But the frightening thing I think is that we are not yet seeing the full impact of global warming in the southern hemisphere. But it's just around the corner.... In all likelihood we're about to see, in the next couple of decades, a very large response to global warming in Antarctic and Southern Ocean regions."

 

The reason for this delayed response is that there is a lag between global warming and Antarctica's response to it. Antarctica and the southern hemisphere are surrounded by large oceans that take a long time to heat and therefore act as a buffer to climate change. Dr. Goodwin said recent evidence suggests the lag time could be up to 60 years. The study was published in the August 11 issue of Science.

 

Click on the following links for the full news stories:  Australian Broadcasting Corporation, University of Newcastle and Science 

 

Satellites Reveal Greenland’s Ice Loss Accelerating Rapidly

 

A new analysis of data from twin gravity-measuring satellites has revealed that the melting of Greenland’s ice sheet has increased dramatically in the past few years. The loss of ice has been occurring about five times faster from Greenland’s southeastern region in the past two years than in the previous year and a half. The changes were documented during a University of Texas at Austin study of Greenland’s mass between 2002 and 2005 and published in the August 11 issue of Science.

 

Dr. Byron Tapley, director of the Center for Space Research and leader of the Gravity Recovery and Climate Experiment (GRACE) mission, said “Our latest GRACE findings are the most complete measurement of ice mass loss for Greenland.... The sobering thing to see is that the whole process of glacial melting is stepping up much more rapidly than before.”

 

Greenland is the second largest reservoir of fresh water on Earth, containing about 10 percent of the world’s fresh water. The Greenland study suggests that the amount of fresh water contributed from the melting of its ice sheet could add 0.56 millimeters annually to a global increase in sea levels, higher than all previously published measurements. The study authors wrote, "If the Greenland cap melted completely, it would raise global mean sea level by about 6.5 meters. If this was to occur, most of the world's coastal regions would be subject to flooding."

 

Click on the following links for the full news stories: University of Texas, San Francisco Chronicle and Cosmos 

 

 

Recent Heat Waves Consistent with Changing Climate

 

While many climate scientists say it is impossible to attribute any one weather event to climate change, recent studies suggest that human greenhouse gas (GHG) emissions have produced both higher overall temperatures and greater weather variability, raising the odds of longer, more intense heat waves.

 

Dr. Paul Della-Marta, a researcher at Switzerland's Federal Office of Meteorology and Climatology, presented findings at an international conference on climate science, held July 24-26 in Gwatt, Switzerland, showing that since 1880 the duration of heat waves in Western Europe has doubled and the number of unusually hot days in the region has nearly tripled.

 

Dr. Claudia Tebaldi of the National Center for Atmospheric Research (NCAR) in Boulder, Colo. said climate models generally agree that looking ahead