The article talks about a temporary phenomenon caused by high-altitude particulates and SO2 blocking the sun. However, these have a comparatively short lifetime

The article talks about a temporary phenomenon caused by high-altitude particulates and SO2 blocking the sun. However, these have a comparatively short lifetime, which is why they don't make a big difference to long-term averages. (That these effects lower the global temperature is nothing new. It's one reason the effect of coal burning isn't as bad as it could be -- the particulates/SO2 partially negate the forcing effect of the CO2 emissions. Of course, once you stop burning coal, these effects disappear quickly and you are left with the CO2. If you open up your copy of the 2007 IPCC assessment report, you'll find this mentioned already on page 4.)