Ciara Shannon's Blog

Ciara loves following the 'rubik cube' nature of sustainability (social, economic and environmental) as it twists and turns the world. Ciara is the Founding Director of Eden Ventures that specialises in sustainability/ climate change issues and has been working under Planet Eden a registered society to bring to Hong Kong an environmental edu-inspiring park. Prior to setting up Eden Ventures, Ciara initiated and ran the Climate Change Business Forum (CCBF) for the Business Environment Council (BEC). Ciara has been a sustainability professional since 2000 and is Hong Kong born.

From the Scary to the Feasible: Geo-engineering

The Best Laid Schemes Of Mice and Men, Go Oft Awry and Leave us Nothing but Grief and Pain.. Robert Burns (1759-1796)
August 13, 2012

Geo-engineering has always been controversial, but when a respected scientist says something is scary, I reckon it’s best to listen: “We don't understand the climate system very well and so trying to engineer a system that is probably unknowable and almost certainly uncontrollable is a very frightening thing," said by renowned geochemist and Harvard University Professor Daniel Schrag.

Scientists have for the last few decades have been doing research on different geo-engineering solutions to slow the pace of climate change and this is happening in an unregulated space, with few international or local governance structures, safeguards or transparency. Most of the geo-engineering technologies fall into two general categories: solar radiation management (SRM) i.e. reduce the amount of sunlight hitting the earth and carbon dioxide (CO2) removal (CDR) i.e. remove CO2 already in the atmosphere.

One of the most controversial SRM options is injecting sulphate aerosols into the stratosphere so as to reflect more of the sun’s rays into space - the thinking behind this is to mimic a volcanic eruption’s cooling effects on the earth. This would be done either by shooting the sulphate aerosols up in artillery shells or releasing them from high-flying airplanes. Once there, they would disperse into a thin haze and reflect sunlight back into space and reduce temperatures.

One potential risk is that the sulphate injections might have to happen repeatedly, and it is unknown what would happen next if they stopped suddenly. Another worry is that it might affect precipitation and that the sulphate particles could also affect chlorine in the atmosphere, converting it to a form that destroys the ozone layer.

Despite the stratospherically dodgy and unknown consequences of this option; benefits include that its relatively quick, could be employed in the near future and comes at a low cost i.e. only a couple of billion dollars a year spent on sulphate aerosols could offset increased temperatures, as effectively as hundreds of billions of dollars spent on low-carbon energy technologies. Other SRM ideas include “seeding” clouds with a fine spray of seawater to make them whiter, or sending mirrors into space etc.
 
Switching now to CDR, the CDR technology most frequently discussed involves the use of large-scale industrial air capture systems that would suck CO2 out of the atmosphere and sequester it in underground stores or recycle it for industrial processes (very similar to the carbon capture and storage technology being developed for coal plants). Backers of this say that it shouldn’t be thought of as geo-engineering as it’s more akin to recycling. While air capture systems are attractive for many reasons, a major hindrance to its development is cost (estimated to cost greater than US$250 per ton of carbon) and the process itself is energy intensive.

Others scientists such as Cornell earth system scientist Charles Greene are looking at air capture devices that could use algal bioenergy as a power source to capture, extract and pipe CO2 for storage or industrial use. Many major international energy corporations are investing in algal biofuel technologies because of the vast production potential of algae. That said, it will still take decades to develop air capture and algal bioenergy systems and scale up the prototypes and deploy systems needed on a global scale.

If none of these ideas are grabbing your interest; there is also ocean fertilisation or ‘ocean iron seeding’. This isn't a new idea, but newly published experimental results suggest that it might actually work. Simply put, it involves dumping iron sulphate in the sea which acts as a metabolic catalyst for algae blooms to grow and soak up carbon which is then deposited in the deep ocean as the algae dies. This method is appealing to some because iron is cheap, available and seeding is relatively easy to do. According to an article in the New Scientist, a global program of ocean fertilization has the potential to remove anywhere from one to three gigatons of carbon from the atmosphere per year, which is between 10% and 30% of the carbon emissions that we produce and would cost approx. US$25 billion Although the costs and carbon mitigation potential are possibly positive, at this point in time, scientists just don’t know what might happen to the composition of some deep sea species if they were to keep adding iron to the sea etc, as well as a host of other unknowns.

I am in two minds on geo-engineering, on the one hand I think some of the CDR ideas are practical and feasible, especially air capture. However, I am very concerned about SRM and that we'd be playing god with our weather. What if it back fires and makes climate change worse? Could rainfall and precipitation patterns be irrevocably altered? What might happen to our lovely blue sky? Would the ozone layer be affected? How else could SRM interfere with the earth's climate? We simply don’t know enough about what kind of climatic or oceanic problems these ‘solutions’ could bring. Much more regulated research is needed to consider the problems and there needs to be international governance to control the research, who deploys it and when.

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