Dispersing fine light-scattering particles into the upper atmosphere could help combat climate change, suggests a member of the Institution of Chemical Engineers (IChemE) and Royal Academy of Engineer- ing chartered chemical engineer Peter Davidson.
The technology involves dispersing benign titanium dioxide particles found in paint, inks and sunscreens into the stratosphere to deflect the sun’s rays.
“We have called for this geo-engineering concept to be properly researched as an insurance policy to cope with the possible catastrophic effects of global warming if we don’t manage to reduce emissions fast enough,” says Davidson.
He explains the concept mimics the earth-cooling effects of large volcanic eruptions, which occur several times during a century.
In 1991, Mount Pinatubo, in the Philippines, erupted and caused a 0.5 ºC global reduction in temperatures.
The eruption released 20- million tons of sulphur dioxide into the stratosphere, forming a fine mist of sulphuric acid particles, which spread around the globe within months.
“Volcanic aerosol particles are similar to the wavelength of sunlight in size, enabling them to reflect some light back into space,” says Davidson.
He claims that titanium dioxide is stable in air, nontoxic and seven times more effective at scattering light than sulphuric acid.
“The total capital cost of the project could be £500- million plus a further £600- million in yearly operating costs, which are about 30 times lower than the next best technologies offered to complete such a mammoth task,” he says.
Further, more than a million tons of titanium diox- ide would need to be dispersed each year for 50 to 150 years to keep global warming under control.