As we touched on in our last post about Geo-Engineering some leading scientific bodies are starting to accept that humanity needs some large-scale CO2 reduction projects to avoid climate devastation. Buying us time, essentially. Or as Dr Tim Fox of the Institute of Mechanical Engineers puts it, Geo-Engineering could be the “silver bullet” in combating climate change.
In light of a recent Royal Society study that concluded many of the proposals are indeed feasible (whilst stressing they are NOT proven and certainly not “the answer”), we thought it may be useful to explain a few of the options and how they work…
Carbon Sequestration techniques seek to capture carbon dioxide emissions and either store them or convert them to harmless gas, in order to curb the inevitable heating that comes with rising CO2. These cover direct methods such as planting fake trees that would absorb carbon dioxide and return oxygen, as described in our last blog. They also include carbon capture and storage ideas for sequestering carbon from coal power plant fumes before they leak into the atmosphere. The UK government believes this will allow coal to be part of our future energy mix – they’ve decreed that no new coal power plants will be built unless they can capture at least 25% of CO2 emissions. But interestingly, this is a highly controversial, unproven technology that is thought to be unfeasibly expensive even if it’s possible. It’s one that the Royal Society’s study wrote off.
Carbon Sequestration also includes indirect ways of absorbing carbon dioxide by encouraging the natural environment to do the work itself. For example, algae is a fast growing and highly efficient absorber of carbon. It’s been suggested that iron filings could be distributed around the ocean to force the growth of algae that could soak up vast emissions.
The drawbacks of each could be huge. Such carbon converting machines would be highly energy intensive to build and run, potentially undermining the emissions they reduce. With indirect methods the risk of environmental side effects are huge – for example the consequences of iron fertilisation for marine life and river ecosystems could be severe.
Solar Radiation Management describes methods of cooling the planet simply by not letting as much heat in. Now this is where the Sci-Fi nerds get excited – some of the proposals have been fairly far-fetched!
The last time the volcano Pinatubo in the Philippines erupted in 1991, global temperatures fell by 0.2°C, due to the amount of dust particles thrown into the atmosphere reflecting the sun’s rays. Solar Radiation Management seeks to replicate these phenomena, either by injecting certain stratospheric sulphur aerosol particles into the air, reflecting UV rays from the ground, or by blocking the sun’s light from space.
More modest proposals have been made by Stephen Chu, the US Secretary of Energy and Nobel physicist to simply paint all roofs white, so reflect UV rays back out of the atmosphere. The less rays, the less heat. As you can see from our Shop blog post, this had a fairly mixed reaction! But it does have the bonus of actually being plausible…
Another idea being considered is to build cloud-making ships that would travel the oceans creating reflective clouding, proposed by Stephen Salter. Read more about that here.
And then there’s the Sci Fi: Using giant mirrors in space to reflect the sun’s rays before they even enter our atmosphere. One suggestion has been to send millions of tiny mirrors into space for the next 30 years. At a predicted cost of over $5 trillion, there are probably other cards we should play first.
The thing to remember with Solar Radiation Management is that these techniques do not reduce carbon dioxide in the atmosphere, they just set to cool the earth. They do not address the crux of the problem, and should only be seen as temporary fixes. When CO2 levels in the atmosphere are already higher than a safe amount, we must be looking to bringing these down.
As more proposals come through, Green Energy Republic readers will be the first to find out.
Geo-Engineering should not be seen by politicians at the Copenhagen summit as a way to avoid real carbon reductions and the move to an emission free economy. However, they should be researched further. Unless it’s a very cunning marketing strategy by Dulux, I’d be up for painting my roof white to help save the planet.
Michael
Green Energy Republic
