Geoengineering: workable or way out?

Scientists are exploring bold initiatives to tackle climate changes. But very few believe that meddling with the Earth's system is a bright idea.

7 March 2006
MUMBAI, INDIA

Despite use of clean technologies to prevent catastrophic climate changes, concentrations of greenhouse gases continue to grow. Scientists are now considering radical and contentious methods. But the question is: are such radical initiatives on a global scale feasible or even desirable? 

Let's take a look at some of these proposals.

Some of these methods propose to scrub carbon dioxide (CO2) out of the atmosphere, some to cool Earth directly by veiling it. A more radical idea is to shade the planet with mirrors. The US National Academy of Sciences found that 55,000 orbiting mirrors would reflect enough sunlight to counter about half the doubling of carbon dioxide. But each mirror must be 100 sq km. The manufacturing costs of these are prohibitive, to say the least.

Another idea is the "human volcano" approach. Inspired by studies of the Mt Pinatubo eruption of 1991 and the cooling effect of its sulphur plume, one proposal suggests that naval guns shoot sulphur pellets into the air to increase Earth's albedo, or reflectivity. A few years ago, Livermore physicists Lowell Wood and Edward Teller proposed an idea to cool the Earth with a sheet of superfine reflective mesh - similar in concept to orbiting mirrors. This idea was panned by scientists as being the cause of residual global climate effects. Some of those scientists now admit that the idea may work well.

Perhaps the most radical of all geoengineering concepts involves moving the Earth itself, cooling the planet by shifting its orbit further from the Sun. 

Scientists may explore these ideas seriously but, by and large, they oppose these initiatives on ethical grounds. There are ethical questions of whether we should commit children to a planet that requires constant tinkering. There also legal issues at play here. Prompted by US cloud-seeding attempts in Vietnam, a 1976 international convention outlaws the hostile use of environmental modification techniques. The term "hostile" is usually applicable in a war scenario but is quite loosely defined.

Then there are the cost issues. Many scientists feel that the mega bucks involved can be used to develop energy initiatives. 

For the moment, it looks like geoengeering is an illusory solution. Overall, scientists feel that a more realistic solution would be to reduce energy consumption and limit CO2 emissions.