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Is there a quick-fix for climate change?

Mount Pinatubo in the Philippines exploded in 1991 with terrifying effects. It was the second-largest volcanic eruption of the 20th century and by far the biggest in a densely populated area.

Advanced warning saved thousands of lives before avalanches of molten ash and mud roared down the flanks of the mountain, filling valleys with volcanic deposits up to 200 metres thick and displacing more than 200,000 people.

The eruption’s ash rose 35 kilometres into the air with a menacing cloud, providing a hint into how geo-engineering might stem the effects of climate change. Nearly 20 million metric tons of sulfur dioxide gas was injected into the upper atmosphere where it combined with other materials to form sulfuric-acid particles. These sulfate aerosols acted as a giant sunshade, reflecting solar radiation back into space, thus cooling earth’s surface.

Dispersal of the aerosols around the world in the jet stream caused global temperatures to drop temporarily by 0.5 degrees Celsius for about two years, a level not far short of the increase at that time in the average land and sea surface temperature since the start of the Industrial Revolution.

International climate-change negotiations are intended to prevent ever-larger amounts of greenhouse gas emissions, mainly from burning fossil fuels and clearing forests for agriculture, from spewing into the atmosphere and raising the mean global temperature to 2 degrees C, a threshold for dangerous climate change adopted by the abortive United Nations conference in Copenhagen last December. But in subsequent negotiations there’s been little progress on a binding agreement to take the costly steps needed to reduce global warming gases by preserving forests and deploying low-carbon energy sources, such as nuclear, hydro, wind and solar power, on a wide scale.

The scientific panel advising the UN has warned that without such cuts, the temperature could rise by as much as another 4 degrees C by the end of the century, increasing the risk of dangerous, even catastrophic climate change because of the long-lasting effects of carbon dioxide, the main global warming gas from human activity, once it reaches the atmosphere.

The Royal Society, Britain’s national academy of science, added impetus to moves for further funding and study of geo-engineering, with a 2009 report that suggests, unless future efforts to slow greenhouse gas emission are more successful, additional action is necessary. The report cautions about uncertainties in the effectiveness, costs and environmental impacts of geo-engineering technologies.

A dust storm from inland Australia that swept across the states of New South Wales and southern Queensland in September 2009, deposited thousands of tons of nitrogen and phosphate in the Tasman Sea between Australia and New Zealand, stimulating phytoplankton growth. By one estimate, 8 million tons of carbon dioxide was captured by an extra 2 million tons of phytoplankton.

Of course, geo-engineering raises thorny environmental, geopolitical and governance issues. Would it work as planned without side-effects? Who would decide if and when to deploy geo-engineering techniques? Should the decision be in government hands?

The debate is set to intensify. On October 29, the US Congress received two reports on geo-engineering, both calling for more coordinated research. At about the same time in Nagoya, Japan, an intergovernmental conference to protect global biodiversity proposed a moratorium on large-scale geo-engineering experiments “until there is an adequate scientific basis on which to justify such activities and appropriate consideration of the associated risks.”

The US space agency, NASA, has said that geo-engineering could provide a way to slow global warming until carbon emissions can be reduced enough to prevent catastrophic climate change. Critics worry about the side-effects. Fertilising the seas could cause dead zones and toxic blooms that harm aquatic life. Adding large amounts of sulphate aerosols to the upper atmosphere could cool the planet, stop melting polar ice and slow sea-level rise.

However, interventions might also reduce Asian monsoon rainfall, deplete earth’s protective ozone layer and reduce sunlight for solar power. In addition, it would blur the skies, erode incentives to cut greenhouse gas emissions and do nothing to stop ocean acidification that threatens sealife.

The 2006 climate change report for the British government compiled by Sir Nicholas Stern, former chief economist of the World Bank, called for international action to cut global warming emissions from human activity. The report warned that unless emissions stabilise in 20 years and fell after that, the overall costs and risks of climate change would be equivalent to losing at least 5 per cent of world GDP each year.

Studies show that although the average global temperature could be lowered by seeding the stratosphere, wisps of jet stream might leave some regions too warm and others too cool. Pete Irvine, climate scientist at Bristol University and lead author of a study on geo-engineering impacts, warns of disagreements between countries and regions over any future schemes. He says, “Some may be better off without any geo-engineering while others may do better with a large amount.”

Apportioning the burden of cutting greenhouse gases still causes acrimonious debate among governments after years of negotiation. Putting Plan G into effect is also likely to be fraught with contention.

Michael Richardson, a former Asia editor of the International Herald Tribune, is a visiting senior research fellow at the Institute of South East Asian Studies in Singapore 
© 2010 Yale Center for the Study of 
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