December 18, 2013
Geoengineering Earth’s Climate: Potential, Barriers And Ethics
Ranjini Raghunath for redOrbit.com - Your Universe Online
Artificial clouds that reflect sunlight back into space. A StratoShield that spews sulfur dioxide particles into space like a volcano, cooling the planet’s surface. Microbial blooms that grow on iron injected into the ocean and trap carbon dioxide from the atmosphere. These are some of the latest ideas being tested to combat climate change in an emerging and hotly-debated field called geoengineering.
Geoengineering involves use of technologies that deliberately manipulate the Earth’s climate, in order to bring down the surface temperature or reduce the carbon content in the atmosphere.
A special December issue of the journal Climate Change, titled “Geoengineering Research and its Limitations,” addresses these technologies, as well as barriers, ethics and regulations involved in their research and applications.
“In the past five years or so, geoengineering has moved from the realm of quackery to being the subject of scientific research,” said Rob Wood, co-editor of the issue and associate professor of atmospheric sciences at the University of Washington, in a press release. “We wanted to contribute to a serious intellectual discourse.”
In one chapter, for instance, Wood, along with Tom Ackerman, another University of Washington researcher, proposes the idea of using salt particles to increase moisture content in the air. This would 'seed' more clouds over the ocean which would reflect sunlight back into space – an approach called marine cloud brightening.
Many such new technologies are still in their early stages – most are still theoretical and only a few have been tested in field trials. Yet some of them have already stirred controversy.
The idea of spewing aerosols into space to cool the atmosphere, for instance, was the topic of the Nobel Laureate Paul Crutzen’s 2006 paper in the same journal. A Seattle-based private company called Intellectual Venture Laboratories also pushed the idea, proposing a system called the StratoShield. When installed, the StratoShield would spew several million metric tons of sulfur dioxide into the stratosphere, reducing the sun’s radiation globally by 1.8 percent, they suggested.
But policy makers are worried that the use of these sulfur particles would only contribute to more air pollution, Crutzen wrote in his paper.
Which is why the issue has to come to the forefront, he wrote. “Building trust between scientists and the general public would be needed to make such a large-scale climate modiﬁcation acceptable, even if it would be judged to be advantageous.”
Other technologies showed promise initially, such as the idea of injecting iron into the ocean. Researchers expected that this would boost the growth of micro-organisms that digest iron and trap carbon dioxide from the atmosphere. But field tests show that the technology is not as effective at removing carbon dioxide as initially thought, Wood said.
The special issue also focuses on the proposed Oxford Principles to regulate research and use of geoengineering technologies. One paper by a joint team of UK researchers, spells out the Principles’ functions and proposes ideas for incorporating them into existing government policies.
Another paper by Stephen Gardiner, co-editor, and another University of Washington researcher, addresses the ethics of manipulating the climate. His paper points out that labeling hacking the climate as “a global public good," which many scientists are calling it, might mislead the public into ignoring the ethical issues involved.
“Just spraying sulfates into the stratosphere is not the kind of thing that necessarily benefits everyone, so in that sense it seems a mistake to call it a global public good,” he stated.
Other papers discuss some attractions of the field, calls for the public to voice their opinions, and addressing the uncertainty and risks involved in introducing these ideas into climate change policies.
The special issue was the product of a three-year-long project aimed at introducing the field to the public and highlighting the various issues it faces, especially with climate change escalating alarmingly.
“If you look at the projections for how much the Earth’s air temperature is supposed to warm over the next century, it is frightening. We should at least know the options. Is geoengineering feasible if there were to be what people call a ‘climate emergency’?” Wood stated.
Led by researchers from the University of Washington, the project included a seminar series and a workshop that helped generate ideas for the papers and bring together scientists and specialists from around the world.
Image 2 (below): A conceptualized image of a wind-powered, remotely controlled ship that could seed clouds over the ocean to deflect sunlight. Credit: John MacNeill