After which threshold do anthropogenic greenhouse gasemissions have an effect on global temperature?

Abstract

We employ a Smooth Transition Conditional Correlation (STCC) model and the latest available data to examine for a non-linear relationship between changes in global temperature and anthropogenic emissions of greenhouse gases. Controlling for natural factors which also affect global temperature, we find that anthropogenic climate forcings and global temperature have practically zero correlation before a certain threshold value is reached. In contrast, correlation rises strongly after anthropogenic emissions exceed this threshold. The value of this threshold can be traced back in the mid-1960’s, during the years of the post-WWII economic boom, when a substantial amount of additional greenhouse gases (compared to the pre-industrial era) had started accumulating in the atmosphere due to the burning of fossil fuels from human activities.