Remember when we were supposed to believe that trace amounts of Co2 were a super-powerful climate driver? Never mind

A Bit of Shade for a Warming Planet - ScienceNOW

They put the stratospheric hazes from CALIPSO and from longer ground-based records into a climate model with increasing greenhouse gases. Without the recent extra stratospheric haze, they found, 20% more greenhouse warming would have occurred since 1998 or about 0.07°C.

The smaller eruptions "did get some stuff in the lower stratosphere," concludes climate scientist Alan Robock of Rutgers University in New Brunswick, New Jersey, "and it cooled the planet. Here's one more thing we have to add to the mix" of forces that have been counteracting the strengthening greenhouse lately. The list had included: Pinatubo-scale eruptions, a small decrease in the sun's brightness at the minimum of the solar cycle, an increase in short-lived pollutant hazes from Asia that stay in the lower atmosphere, and decade-long variations of climate spurred by El Niño and other natural climate movers. And now Solomon and her colleagues allow that some of the lower-atmosphere pollution may be leaking up into the stratosphere as well, as the late David Hofmann—an atmospheric scientist at the National Oceanic and Atmospheric Administration in Boulder—recently suggested.