Geo-engineering: deliverance from Climate Change, or dangerous distraction?

In the late 1940s, both the United States and the Soviets drew up plans to alter the global climate in ways that would deliver them geopolitical advantages. Soviet climatologists suggested using nukes to melt the Arctic, making their territory more agriculturally productive. The US developed ‘Operation Stormfury’ in 1962, attempting to ‘seed’ clouds with particles intended to dampen the ferocity of tropical hurricanes.

The potential harm of these proposals for large-scale unilateral climate modification spurred the United Nations to adopt the Convention on the Prohibition of Military or Any Other Hostile Use of Environmental Modification Techniques in 1976. At that point, such schemes were largely abandoned.

In recent years, due to growing concern over the predicted devastating impacts of climate change, ‘geo-engineering’ is being resuscitated as a viable policy option. Defined by the Royal Society as “the deliberate large-scale manipulation of the planetary environment to counteract anthropogenic climate change,” geo-engineering schemes have been suggested by Nobel-Prize winning scientists, the National Academy of Sciences, and debated in the British parliament.

Notably, President Obama’s National Science Advisor, John Holdren, has voiced qualified support for investigating the possibility of such radical policies, saying “It’s got to be looked at…We don’t have the luxury of taking any option off the table.”

As the American Meteorological Society notes, there are three general approaches to addressing climate change: 1) mitigation, reducing emissions, 2) adaptation, increasing our ability to adjust to the effects of climate change and 3) geo-engineering, large-scale intervention in the climate on a planetary level.

Suggested geo-engineering schemes range from giant underwater pump systems delivering more ice onto the Arctic icecap, fertilising oceans with iron to make them absorb more carbon, putting giant space mirrors into orbit to reflect solar radiation, and storing carbon in the deep ocean.

Perhaps the most commonly discussed method to engineer the climate is the proposal to launch reflective particles into the troposphere. This idea gained attention when it was proposed by atmospheric chemist and Nobel laureate Paul Crutzen. Sulphur dioxide particles would increase the reflectivity of the Earth’s atmosphere, meaning that less solar radiation would be trapped and contribute to warming the Earth’s surface, thus producing an ‘artificial cooling’.

Some claim the proposal has merit because it mimics a naturally-occurring process: volcanic eruptions. Upon eruption, volcanoes emit large amounts of sulphur particles which have just this effect. The eruption of Mount Pinatubo in 1991 reportedly resulted in a global cooling of around 0.5 degrees.

It’s easy to see the allure of such projects.

Compared with the alternatives of mitigation and adaptation, they’re cheap, they would work instantly, and – perhaps most crucially – they might end up being our only choice when political inaction on the issue brings us to the so-called ‘tipping point’. Indeed, many of geo-engineering’s most vocal advocates cite international policy paralysis on climate change, along with the likelihood of humanity reaching the ‘point of no return’, as key reasons for their support. Simply holding global temperatures at their current levels would require an immediate reduction of greenhouse-gas emissions of between 60-80%.

Many proponents are also careful to stress that geo-engineering need not be a standalone solution, but part of a comprehensive strategy involving elements of mitigation and adaptation as well. Humanity has also historically been susceptible to naturally-occurring as well as human-induced climate change. Considering this, geo-engineering strategies become more compelling, given that mitigation would have a more limited ameliorating effect on periods of naturally-occurring warming or cooling.

Yet the risks and unknowns involved in geo-engineering should offer pause.

Take the proposal for using tropospheric reflective particles. If sulphur dioxide wasn’t sufficiently dispersed, regional concentration could result in acid rains, damage to the ozone layer, and dimmed visibility. Our understanding of how this would affect precipitation patterns is also limited. In the months subsequent to the eruption of Mount Pinatubo, for example, rainfall and river flows nearby dropped precipitously. It’s possible that these kinds of schemes would increase rainfall over the oceans and decrease rainfall over land, resulting in lower agricultural yields, global food shortages and increased droughts.

In 2002, the Journal of Climate indicated that major droughts in the Sahel region of Africa in the 1970s and 80s were caused by sulphate pollution from North American and Europe, which altered precipitation patterns by pushing the rain belt south of the Sahel.

In an article in the journal Science Gabriele Hegerl of the Grant Institute at University of Edinburgh and Susan Solomon of National Oceanic and Atmospheric Administration warn that geo-engineering may see significant reductions in regional rainfall, creating winners and losers among humanity, and even conflicts over fresh water.

This raises a host of ethical questions over the use of geo-engineering. If any plan produces winners and losers, who gets to determine what strategy is used and where? The website RealClimate asks “…how does anyone balance temperature changes that effect ice sheets versus the failure of the Indian Monsoon? The Amazon drying up versus the North Atlantic overturning circulation? It would make the current international climate negotiators seem rather like medieval theologians.”

We would also have to be very precise in our estimations of predicted warming. If, say, leading climatologists predicted a 4 degree temperature rise by 2050, but in reality there was only a 2 degree rise by this point, we would overcompensate with the amount of sulphur deposited and induce cooling that could potentially plunge the Earth into an Ice Age!

There is also the fact that many of the proposals on offer only target the warming effect of carbon concentration. While this might be the most threatening aspect of the atmospheric build-up of carbon, it is hardly the only one. None of the schemes deal with ocean acidification, for example. As the oceans absorb more carbon, this is expected to eventually result in anaerobic ‘dead zones’ devoid of oxygen. Larger marine predators and shell-making organisms would cease to be viable in such environments.

Opponents also claim that geo-engineering schemes threaten to compete with mitigation and adaptation strategies, attracting political and financial capital that would otherwise be spent on these approaches. In this case, geo-engineering would come at the expense of other strategies, and not in concert with them, as some of its supporters claim.

Doug Parr, chief scientist at Greenpeace, is among those who believe that geo-engineering presents a dangerous distraction from addressing climate change. “The scientist’s focus on tinkering with our entire planetary system is not a dynamic new technological and scientific frontier, but an expression of political despair.”

What is certain is that uncertainty abounds when it comes to interfering with the atmosphere and biosphere. Climate change itself is an unintended consequence of human mass-manipulation of ecological systems. The limitations of our knowledge and potential fallout of further large-scale climate manipulation should therefore be at the forefront of the minds of policy-makers in any future decisions regarding the desirability of geo-engineering.

As published in Contribute Magazine (The University of Queensland’s United Nation’s Association’s annual publication), August 2014. Co-authored with Jack Shield.

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