Geoengineering: Paint particles plan to fight climate change

By Adrian Bishop - 11 May 2012 15:26:16 GMT
Geoengineering: Paint particles plan to fight climate change

Five tethered balloons would loft 1.5 million tonnes of titanium dioxide particles into the stratosphere each year. The balloon size is far larger than any launched to date to avoid 'blow over' from the fierce winds that the tether will experience 10 km above the Earth. The cost of the technology is significantly cheaper than other proposed stratospheric particle injection systems such as aircraft, artillery, and even tall towers. (Credit: IChemE/A Revell)

Another geoengineering idea for a solution to climate change - but could it work? An alternative solution to climate change could be to distribute fine paint particles in the upper atmosphere, says a UK chemical engineer. Scattering benign particles of sub-micro titanium dioxide into the stratosphere could turn away the rays of the sun, says Peter Davidson.

The former government senior innovation advisor, chartered chemical engineer and Fellow of the Institution of Chemical Engineers (IChemE) and Royal Academy of Engineering says, "While it's essential that we work to reduce carbon dioxide emissions now, it would be wise to have a well-researched emergency system in reserve as a Plan B."

The geoengineering concept, which has been developed in Britain and first published in The Chemical Engineer (tce magazine), should be used as an option to tackle global warming if other solutions are not effective in reducing carbon emissions.

The concept of employing titanium dioxide, which is also used in sunscreens and inks, is similar to the way volcanic eruptions cool the earth.

In 1991, temperatures around the world fell 0.5 degrees Celsius following the eruption of Mount Pinatubo in the Philippines, which launched 20 million tons of sulphur dioxide into the atmosphere. This caused fine sulphuric acid particles to quickly cover the earth.

As fine volcanic particles resemble solar wavelengths, they dispersed around 1% of light back into space, reducing temperatures.

To recreate the conditions using sulphuric acid would deplete the ozone layer and produce changes in the regional patterns of rainfall.

But using a harmless particle of a similar size is used, such as Titanium Dioxide (TiO2), could be the answer, says Mr Davidson.

Titanium Dioxide is not only stable in air and is not toxic, but it is seven times better at dispersing light than sulphuric acid. It is commonly found in the planet's crust and five million tonnes is already produced each year for use in paints, inks and other applications.

The next problem is to come up with a cost-effective way of transporting millions of tons of particles around 65,000 feet (20km) into the air, preventing them from being quickly washed away and keeping them there for a few years.

He suggests five massive tethered balloons, kept afloat by high-pressure pumps, which could cost around £600m a year - 30 times cheaper than other options such as jets - could transport 1.5 million tonnes of titanium dioxide particles into the atmosphere.

Other suggestions for transporting the particles, such as giant space mirrors and towers 65,000 ft high, would be much higher and may not be developed this century, he believes.

Mr Davidson says an independent trust should be formed to spearhead the project and draw together governments, environmental bodies, legal representatives and other key influencers.

If temperatures caused by climate change are to be sufficiently reduced they more than a million tonnes of titanium dioxide may need to be scattered each year for up to 150 years. The cost of supplying the particles could be around £3 billion a year.

One unwelcome side effect might be the acidification of the oceans, but the effects on sea levels from melting glaciers caused by global warming would be worse.

Mr Davidson says it is crucial to come up with other plans to combat climate change and that more investigation, research and debate is required about the titanium oxide option.

The full research article can be found on :The Chemical Engineer.

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