On almost all time scales, natural changes in greenhouse gas concentrations appear to affect climate. (reddit.com)
The effect of these small orbital changes was amplified by positive feedbacks, such as changes in greenhouse gas levels. (newscientist.com)
The 1998 - 2008 hiatus is not the first period in the instrumental temperature record when the effects of anthropogenic changes in greenhouse gases and sulfur emissions on radiative forcing largely cancel. (pnas.org)