Experts weigh in on the definition and context of a new term.
The deliberate, large-scale manipulation of the Earth’s climate to reduce the accumulated impact of anthropogenic changes to the climate; also known as climate engineering
In July 2012, American entrepreneur Russ George dumped 120 tons of iron particles into the ocean off the west coast of Canada. As consultant to the local council of a nearby indigenous village, he convinced them that the resulting algae bloom would lure salmon and restore the local fishing industry. Further, the uneaten algae would soak up carbon dioxide (during photosynthesis) and carry it to the bottom of the ocean when it dies — thus reducing the amount of greenhouse gas in the atmosphere.
The technique, iron fertilization, is one of many geoengineering approaches that could theoretically reduce mankind’s impact on the planet. Efforts have been focused around two categories: changing the reflectivity of the Earth (solar radiation management) and taking carbon dioxide out of the atmosphere (carbon dioxide sequestration).
“It sounds like an attractive idea,” says Jennifer R. Smith, PhD, dean of the College of Arts & Sciences and associate professor of earth and planetary sciences. “With geoengineering, we can live the way we want and don’t have to worry about the specter of climate change. But for every plan, there are known risks and hazards, and then there are unknown risks and hazards.”
“The concern is that if you even talk about
geoengineering ideas, people will lose interest in making the hard
decisions to reduce greenhouse-gas emissions.” — David Fike, PhD, assistant professor of earth and planetary sciences in Arts & Sciences.
In spring 2013, the National Academy of Sciences began a technical evaluation of a limited number of geoengineering techniques, with the goal of determining their feasibility and their possible impact on environmental, economic and national-security concerns.
The science, says Brent Williams, PhD, the Raymond R. Tucker Distinguished I-CARES Career Development Assistant Professor in the School of Engineering & Applied Science, can be iffy. One strategy, for example, calls for the injection of sulfates into the atmosphere to reflect the sun’s rays, replicating the after-effects of a volcanic eruption, which is known to decrease the Earth’s global temperature. “The problem is that the effect only lasts for a year or two, then temperatures warm again because greenhouse gases have lifetimes of hundreds to thousands of years in comparison,” he says. “We would have to continually inject particles to maintain the cooling effect. These particles would eventually settle to the surface and cause acidification of the oceans and soils, having detrimental effects to life on the planet’s surface.”
David Fike, PhD, assistant professor of earth and planetary sciences in Arts & Sciences, notes that the approaches treat the symptoms of climate change but don’t treat the problem. “The concern is that if you even talk about geoengineering ideas, people will lose interest in making the hard decisions to reduce greenhouse-gas emissions.”
Further, the regulation of geoengineering experiments is unclear. In the United States, the Clean Air Act limits concentrations of pollutants (which would include sulfates) at ground level, but there is no regulatory scheme for upper-atmosphere activity, says Maxine Lipeles, JD, senior lecturer in the School of Law.
Scientists condemned Russ George’s iron-fertilization experiment, claiming it violated two international conventions on dumping in open seas. George, however, insists the conventions aren’t binding and, pointing to the resulting 10,000-sq.-km. algae bloom, claims success.
Will humankind have the luxury of choosing whether to pursue geoengineering strategies? The Intergovernmental Panel on Climate Change forecasts a temperature rise of 2.5 to 10 degrees Fahrenheit over the next century. That prediction makes the National Academy of Science’s top-level investigation seem all the more prudent. “It may no longer be an either/or situation, but an and,” Smith says. “The last thing we would want is to have to rush through the science in desperation and haste.”