This was due to a combination of factors: a less active sun, higher levels of cooling aerosols from volcanoes and Asian factories, and increased heat uptake by the oceans. (newscientist.com)
In suggesting climate shifts as the cause, the authors offer no physical explanation as to why the warming sun and cooling aerosols didn't have their expected effect? (skepticalscience.com)
While SO2 emissions may have had some small role in that period, they can't have a role in the current standstill, as the increase of emissions in SE Asia is compensated by the decrease in emissions in the Western world, thus there is hardly any increase in cooling aerosols while CO2 levels are going up at record speed and temperatures are stalled. (climateaudit.org)