Controversies in Science/Are humans causing global warming/A Critique of Global warming and human activity: A model for studying the potential instability of the carbon dioxide/temperature feedback mechanism,Ecological Modeling.

Global Warming & Human Activity
There is a link between carbons released due to human activity and a shift in the global climate.

Method
The method used for the purpose of this study is control theory. It uses system identification techniques to find the transfer functions that assume the potential measurement of the system. In this study, four black-box models are combined and linked in a feedback loop structure. Two types of data were used in the study; both measured and reconstructed data according to the time series being considered (1610-2004). The methods used for gathering data between the time periods of 1610 and 1856 included tree ring and ice core collection and therefore included reconstructed data. For the time period between 1857 and 2004, more measurable and instrumental processes were used to gather data relating to temperature, carbon dioxide atmospheric concentration, anthropogenic carbon dioxide emission and solar irradiance. The focus of the study was to test the stability of the carbon dioxide-temperature feedback structure and the influence of anthropogenic carbon dioxide emissions on the transfer system.

Results
By starting with a basic feedback structure between carbon dioxide and temperature and using a feedback model to describe the relationship between anthropogenic carbon dioxide emissions, global temperature and atmospheric carbon dioxide it was concluded that anthropogenic carbon dioxide has become a significant factor in global warming. The study also warns that the instability of the feedback structure between carbon dioxide and temperature has reached a critical level, and that the carbon dioxide due to human activity has disrupted the equilibrium to the effect that possible repercussions for global warming are unpredictable and unknown at the current level of instability.