Either it's a typo or I'm missing something, but the following line from the article doesn't quite make sense,

"...the lower than expected temperature rise between 2000 and the present could be explained by increased emissions from burning coal."

The only thing I can think of, if it's not a typo, is that coal does not emit as much CO2 as other fossil fuels per unit burned or energy produced, thus by burning coal instead of another fossil fuel, less CO2 is emitted.

Brian