Understanding the Role of Clouds

When most people see clouds, they only search for patterns, maybe in the shape of a dog, baby or building. But some experts look up in the sky and see a possible direction for our planet's future. As the world gets warmer, more and more water vapor will make its way into the atmosphere, which is a very dangerous phenomenon. The vapors are just as efficient as other greenhouse gases in trapping heat on the planet, making climate change move faster, and increasing global temperatures substantially.

According to investigators, the build-up of water in the atmosphere will trigger yet-undiscovered consequences. “We're seeing that now. We just don't know what this will mean for how clouds might change, and for Earth's temperature and climate. Although a small change of clouds – for example, more low clouds – in the right direction would mitigate the effects of increased carbon dioxide, a small change of clouds in a different direction – for example, more high clouds – would amplify the warming caused by increasing carbon dioxide,” says Graeme Stephens.

He is the principal investigator of the NASA CloudSat mission, a spacecraft which was launched in 2006, in an attempt to make more sense of the influence clouds have on Earth. The expert is based at the Colorado State University in Ft. Collins. The experimental satellite was built and is managed by the NASA Jet Propulsion Laboratory (JPL), in Pasadena, California. According to Stephens, calculating the balance between the cooling or warming effect of clouds and the warming effect of greenhouse gases is a complex problem, and one that CloudSat aims to solve.

“In all ways, shapes and forms, clouds influence life on Earth – including our climate,” the expert says. He adds that clouds keep the planet habitable above all other things. They reflect a large amount of sunlight back into space, helping keep the surface of the planet at temperatures low enough to prevent water from boiling and evaporating. But they also trap heat that manages to pass through them, preventing it from escaping back to space. Determining which of these two “behaviors” is dominant is part of the aforementioned complex issue, climate scientists say.