Nanotechnology principles and materials are used in a number of scientific disciplines. Scientists in a field called geoengineering are investigating ways to counter the global warming attributed to high levels of carbon dioxide in our atmosphere.

Volcanoes have provided these scientists with a one way to cool the earth. When a volcano erupts, it sends clouds of particles and gasses into the atmosphere. These clouds contain sulfur dioxide, which can rise as high as the stratosphere. At that height, the sulfur dioxide combines with water vapor and produces sulfuric acid aerosols that reflect the sun’s energy, reducing the heat that gets through to our atmosphere.

When the sulfuric acid returns to earth in rain, the side effect is acid rain. There’s always something.

The resulting lowering of the atmosphere’s temperature can seem small, but it can be significant in terms of its effect on our environment. For example, the U.S. Geological Survey estimates that an eruption of Mount Pinatubo in the Philippines in 1991 sent about 20 million metric tons of sulfur dioxide into the atmosphere and caused about half a degree centigrade (about 1 degree Fahrenheit) cooling in the northern hemisphere.

Here’s where nanotechnology comes in. A researcher at the University of Calgary has designed particles composed of different nanofilms that could be released into the atmosphere to cool the earth without some of the negative effects caused by volcanoes.

The top layer of a nanofilm protects the middle layer from oxidizing; the middle layer reflects light; and the bottom layer interacts with the atmosphere’s electric field to orient the disk-shaped particle horizontally for optimum reflection. That reflection cuts down the amount of sunlight that reaches our atmosphere and helps cool our planet slightly to compensate for global warming.