Scientists have debated the cause of the hiatus. Could it be the result of a prolonged period of reduced solar activity? Or a cooling of the tropical Pacific Ocean due to a global weather pattern known as La Niña?

Researchers now say they have identified another possible cause: According to a study in this week's issue of the journal Nature Geoscience, led by climatologist Francisco Estrada of the National Autonomous University of Mexico and Vrije Universiteit in Amsterdam, the global warming pause is an unintented consequence of an international ban in the late 1980s against chlorofluorocarbons, or CFCs, chemicals that were destroying the Earth's ozone layer.

In their study, Estrada and his team used a statistical method to match