Colloquium explores URI global warming engineering projects

10/29/08 - In a couple of decades, if you see a giant air filter or hear about a bunch of lenses in space, you're seeing evidence of engineering projects to prevent the planet from warming.At last night's Fall 2008 Honors Colloquium, University of Rhode Island professors Jim Opaluch of CELS, and Art Spivack of oceanography, investigated projects that aim to either increase the earth's ability to reflect the sun's rays or decrease the amount of carbon dioxide in the atmosphere. Either approach will end in the same way: global temperatures will remain stable, and both human and non-human life will survive.

Opaluch and Spivack took information presented during the last several speeches and analyzed solutions. Past speakers have made scientific assertions that ice sheets will melt and arctic life would suffer; rising temperatures will cause heat waves, which could kill humans; and carbon dioxide would reduce the pH of the ocean, threatening aquatic life.

At the end of the speech, Opaluch and Spivack provided their verdict on geoengineering, the term used to describe global warming mitigation projects. Each professor's verdict struck a balance between ethical issues facing geoengineering and the possible rewards of those projects. Some of those ethical questions ask if humans have the right to intentionally alter the environment.

"I like to think of geoengineering as a life boat," Opaluch said. "You're not going to ignore leaks in your ship just because you have a life boat . but in a worst case scenario, a life boat is going to buy you some time."

Spivack's verdict praised the possible rewards of geoengineering, but emphasized regulation of projects.

"There is not going to be a silver bullet on this," he said.

The projects Opaluch and Spivack investigated were a large carbon scrubber, which would remove carbon dioxide from air, a series of lenses in space, an ocean fertilizer and sulfur dioxide in the atmosphere.

Spivack said one of the challenges of the projects is their unregulated nature.

"I think we need to build international institutions and discuss these [projects] and set up limitations," he said, pointing out that one country, a corporation or even one very rich person could institute any project.

The consequences could be almost as adverse as the effects of global warming.

The panel gave the sulfur dioxide good overall ratings in a presentation-concluding "report card," for all the projects. If sulfur dioxide entered the atmosphere, it would reflect some of the sun's rays, cooling the earth. The cost of putting it in the air would be an estimated $25 billion to $50 billion a year, the panel said. It could be implemented quickly and is fairly reversible, because the particles dissipate within a year if there were negative side effects.

But those side effects could be dangerous, the panel said. Opaluch said there could be acid rain, reduced evaporation in the earth's atmosphere, which would disrupt the water cycle and sulfur dioxide could also change ocean and wind currents.

Carbon scrubbers received decent overall ratings. While the scrubbers would have a high cost and would take a while to implement, if negative side effects were occurring they could simply be shut off.

The side effects of the scrubbers would not be that bad, only that they would only absorb carbon dioxide and not other greenhouse gasses. But they would be extremely expensive, and Opaluch said it would be more efficient for humans to simply reduce their carbon dioxide emissions. But the absorbed carbon would need to be put somewhere, and if it went to the ocean it would reduce the pH of the ocean.

"At lower pH levels, many forms of life in the ocean will be inhibited," Spivack said, adding later, "With enough carbon dioxide in the atmosphere, many organisms won't be able to live on the surface of the ocean."

Sun shields also received decent ratings. They are small lenses that would be deployed into space one million miles from the earth, where gravity wouldn't affect them. One trillion lenses would be needed. Such lenses would be extremely costly, and a National Geographic documentary the panel showed the audience said the estimated cost is greater than the amount of goods and services the entire world produces in a year.

It would be time consuming, because the panel pointed out that one million mirrors would have to be deployed every minute for 30 years, and they would need to be replaced every 50 years, barring unexpected damage. But they are reversible, because they have navigational devices, which could be tweaked if they block too much sun, and because of their flexibility, side effects are minimal, the panel said.

Ocean fertilizer received neutral ratings in all categories on the report card, because little is known about the cost and time involved. Iron would be put into the ocean, which would stimulate algae growth. The algae would absorb carbon dioxide and turn it into oxygen. It is unclear, the panel said, how long it would take to work. The reversibility is also largely unknown, and so are the side effects. The major side effect is that when the algae dies, it would likely sink to the middle of the ocean and re-emit carbon dioxide.