At the Natural Energy Laboratory of Hawaii on the sun-splashed Kona Coast, a pipe drops steeply from coastal lava fields through azure waters to depths of 1,000 feet. At some point during the next year, scientists will send liquid carbon dioxide coursing through the pipe and into the Pacific Ocean.
The goal: to find out whether it's safe to use the earth's oceans as storage bins for massive amounts of carbon dioxide (CO2) - a greenhouse gas linked to global climate change.
For environmentalists, the experiments represent a red herring that could encourage even greater greenhouse-gas emissions and divert resources from more valuable climate-change efforts. But for some scientists, the international project represents an elegant solution to the worsening problem of CO2 emissions and fossil-fuel dependence.
"It will allow us to use fossil fuels without carbon emissions," says Howard Herzog, a research engineer at Massachusetts Institute of Technology in Cambridge.
Carbon levels in the earth's atmosphere have gone up about 25 percent since the Industrial Revolution, largely because of the combustion of coal, oil, and natural gas that supply about 85 percent of the world's energy needs. And that level is increasing.
"It's not only the higher levels that we are worried about," says Gerard Nihous, an ocean engineer with the Pacific International Center for High Technology Research. "It's the rate of change. Rapid changes in the atmospheric chemistry might create rapid changes in climate."
Meanwhile, fossil-fuel consumption - spurred by low oil prices and industrialization in the developing world - continues to skyrocket. The use of renewable energy, such as wind and solar power, is lagging considerably. And nuclear energy, which produces almost no greenhouse gases, is a public pariah. In addition, the cutting down of forests that soak up greenhouse gases is outstripping reforestation.
Furthermore, scientists say even the expected advances in all of these energy methods will not be enough to stabilize, let alone reduce, CO2 emissions.
How to reduce emissions
All these reasons make the industrialized nations' target for emissions reduction look even more daunting. By 2012, they want a 5 percent to 8 percent reduction in greenhouse-gas emissions from 1990 levels.
As an alternative and complementary solution, scientists are proposing injecting CO2 into the ocean. The gas, to be captured from flue gases and other power producers, will be injected at depths of 1,000 feet or more via pipes that may be based on land or dragged under specially outfitted oil tankers.
By putting the CO2 under high pressure, the gas will remain in liquid form and stay in the ocean for several centuries before bubbling to the surface. This, scientists claim, will give humans the breathing room to continue to use fossil fuels until more efficient technologies are developed, emissions are reduced, or fossil fuels become scarce and expensive.
The benefits to this proposal are clear. Technology to capture CO2 with special solvents and convert it into a liquid already exists. And to capture the CO2, power plants would only need to retrofit their facilities with new equipment, they wouldn't have to construct a whole new power- supply system.
These two factors mean that CO2 capture would most likely be considerably cheaper than other solutions.
It's happening anyway
Most important, say project scientists, is the fact that the oceans are already the planet's largest reservoir of carbon gas. They absorb between 50 percent and 80 percent of the carbon produced by humans.
"There's a huge exchange between the atmosphere and the ocean," says Stephen Masutani, a University of Hawaii engineer working on the Kona project. "The bottom line is, it's happening anyway."
But CO2 storage in deep oceans is no slam-dunk. Capturing the CO2 from power plants and other carbon emitters will initially increase the cost of power by 50 percent to 100 percent, something that will meet resistance from utilities, car manufacturers, and consumers.
How to distribute the cost equitably among countries is also problematic. Also, funding for CO2 capture - although dramatically increased over previous years - is minuscule when compared with government and private funding for clean-burning technologies and strategies for greenhouse-gas mitigation.
Down with 'ocean dumping'
Many environmentalists vow to oppose the CO2 storage, which they have dubbed "carbon dumping." They say efforts to capture carbon, let alone put it in the deep ocean, are misplaced. They fear that higher CO2 levels will harm marine life due to increased acidity, something the scientists hope to study during the experiments.
Critics also note that the oceans are warming, and they question whether this will result in the CO2 bubbling up quickly, escaping into the atmosphere.
Besides, environmentalists say that figuring out a way to allow mankind to maintain and even increase current levels of fossil-fuel consumption is a misguided goal in the first place.
"The whole purpose of this exercise is to stabilize atmospheric gases at a level that will avoid dangerous climate change," says Gary Cook of Greenpeace USA. "People are not considering what the implications of increasing fossil-fuel-burning activities have on that objective. I don't know any environmental group who is in favor of ocean dumping."