Geoengineering gets closer look as a 'Plan B' in case emissions don't fall

We can probably engineer Earth's climate to cool the planet, scientists say, but are we willing to live with the downsides? Those could include creating more droughts, more ozone holes and, oh yeah, a thin cloud layer that obscures blue skies and gives astronomers fits.

With potential negatives like that it's no wonder that "geoengineering," as the technique is called, has few hardcore advocates.

Instead, a growing cadre of scientists is asking whether it should be a "Plan B" in case emissions of greenhouse gases aren't reduced in time to head off major consequences.