The Sahara contributes about half of all of the dust dumped into the atmosphere every year. This image shows the dust trail blowing west over Africa and across the North Atlantic before heading north at the Cape Verde islands. Saharan dust regularly travels as far as South America, helping to fertilise the Amazon rainforest.
Earlier this week the University of Alabama in Huntsville announced a three-year project looking at how Saharan dust affects atmospheric temperature. The large dust particles can both absorb solar radiation, converting it to heat, and reflect radiation back into space, and thus having a cooling effect.