Time magazine: When it was warming, the reason was CO2 and climate was simple; now that it's not warming, the reason isn't known and climate is complex

Climate Scientists Issue Their Report. Now It’s Our Turn | TIME.com

Climate skeptics have seized on the fact that the rate of warming over the past decade or so has been less than climate scientists predicted given the continued increase in carbon emissions. The IPCC report address the warming “hiatus,” as it’s been called, raising a number of possible explanations—the ocean absorbing the warmth, changes in the solar cycle, volcanic eruptions that cause cooling—without pointing the finger at a single one. Which just underscores how complex the climate system remains, even as we keep experimenting on it. The scientists will keep working on those questions and others...