Can man-made ‘volcanoes’ slow down climate change?

Eruption of Mount Pinatubo in the Philippines in 1991. Wikipedia

Britain’s Royal Society thinks it may have found a way to cool down the planet. The Society is backing research into the "volcano" idea, which simulates the effects of volcanic eruptions which spew enormous quantities of dust into the atmosphere.

The Royal Society is Britain and the Commonwealth’s biggest and most prestigious independent scientific academy, and this week sees the launch of its new drive for a major programme of studies designed to determine how geo-engineering could help to reduce the rate of global warming, says The Times.

Geo-engineering is defined by the Society as being "the study and use of options that would involve large-scale engineering of our environment in order to combat or counteract the effects of changes in atmospheric chemistry.”

The initiative begins in the midst of many uncertainties concerning the possible outcome of the United Nations-sponsored climate talks in Copenhagen in December which are supposed to agree on global cut quotas in carbon dioxide emissions. Previous talks have not led to substantial progress being made on the issue and many scientists consider geo-engineering to be a kind of “Plan B” if the talks fail.

One major geo-engineering option that the Society supports is the introduction of sulphur-based particles into the upper-atmosphere.

Ken Caldeira is an earth scientist at Stanford University, California. He is also a member of a Royal Society working group on geo-engineering and he says that the theory behind the idea is that the particles would reflect the sun’s rays, along with the heat that they carry, back out into space.

Caldeira seems so sure of the idea’s feasibility that he says, “If I had a dollar for geo-engineering research I would put 90 cents of it into stratospheric aerosols and 10 cents into everything else.”

The origins of the so-called stratospheric aerosol theory date back to the eruption of Mount Pinatubo in 1991. It was the second biggest volcanic eruption of the 20th century and it propelled up to 20 million tons of extremely small sulphur particles into the atmosphere. Those particles cooled the planet by around 0.5 per cent before they finally drifted back down to earth.

The interest in so-called aerosols is linked to the eruption of Mount Pinatubo in the Philippines in 1991, the second largest volcanic eruption of the 20th century. The explosion blasted up to 20m tons of tiny sulphur particles into the air, cooling the planet by about 0.5C before they fell back to earth.

Brian Launder, a professor at Manchester University and a working group member said that in the absence of CO2 emission reduction or geo-engineering “civilisation as we know it will end within our grandchildren’s lifetime.

“The only rational scheme is to reduce the sunlight reaching Earth and to reflect back more of it.”

Some scientists think that the planet’s temperature could rise by 5C before the year 2100 and they predict that CO2 emissions must fall to 20 billion tons a year by 2050 if a disaster is to be averted.

The Royal Society is pressing ahead with its support for the plan despite the doubts expressed by some scientists that CO2 emissions could drop quickly enough by adopting it, or that using it would mean that if ever they stopped, the earth would heat up disastrously quickly.

Tim Lenton, professor of earth sciences at the University of East Anglia, has just finished research which compares the different ideas for geo-engineering. His research will be used by the Society.

Lenton says that the results mean that “We estimate that 1.5-5m tons of sulphate particles could be released [artificially] into the stratosphere each year on a recurring basis. That is quite a small amount, which makes it potentially economically viable, but it could reduce global temperature rise by up to 2C.”

He thinks that the idea of “man-made volcanoes” is the most promising of all the other geo-engineering projects he studied.

They were:

• Giant sun reflecting mirrors in space (“Science fiction” says Lenton.)
• Artificial cloud-whitening for sun reflection (Said to be a risk to rainfall levels.)
• Using chemicals and plankton to accelerate the rate of CO2 elimination from the air. (Too long to implement.)

Lenton’s research and the Royal Society’s support mean that the “man-made volcanoes” project would seem to have time to prove its worth from further research.

Michael Cosgrove is a Lyon, France-based freelance journalist, business translator, and interpreter and teaches English to French businesspeople. He publishes frequently at Digital Journal.com