Titanium dioxide: Sunscreen for the Sky

 

Photo courtesy of monkeyatlarge

Global warming. A term most are familiar with, a topic constantly under discussion, an area relentlessly being researched. And now, scientist have come up with an new, and very ambitious, geoengineering project, the basic idea of which involves spraying a sunscreen-like ingredient into the stratosphere in an attempt to counteract the effects of global warming.

The ‘sunscreen ingredient’, titanium dioxide, is a nontoxic chemical found in many everyday products such as sunscreen, paints, inks and even food. Millions of tons of titanium dioxide particles would be dispersed using high-altitude balloons with the idea that the particles will spread around the planet and reflect some of the sun’s rays back into space.

The idea was inspired by the 1991 eruption of volcano Mount Pinatubo in the Philippines. The eruption emitted so much sulphur dioxide into the stratosphere that global temperatures decreased by a half a degree Celsius for two years. Yet sulphur dioxide is harmful to not only the ozone layer (it degrades it) but also in that it may lower temperatures too much as it absorbs as well as scatters light, disrupting stratospheric circulation. Titanium dioxide, on the other hand, is seven times more effective at scattering light meaning that much less is needed to achieve the desired outcome, resulting in a much lower impact on atmospheric circulation.

While scientists claim the impact of this chemical on the environment will be minimal, history has shown us that injecting chemicals into the atmosphere almost always has a negative impact (CFCs, which degrade the ozone layer, are the prime example). The project is decades away from safely being launched, and it is still very controversial as to whether it should be carried out at all. The main worry with geoengineering solutions is that they distract from the real problem – rising levels of harmful greenhouse gases. The concern is that this project could be seen as an ‘easy fix’, resulting in policy makers believing they need to do less work to tackle the core issue of increasing greenhouse gas emissions. On the other hand, it is argued that humanity is in dire need of an insurance policy against the possible catastrophic events of global warming.

By Lea Fraenkl