Many studies have applied either the CBA or MC approach to
estimate the social costs of CO2 emissions. For example, Cline
(1992) used the CBA approach to estimate the social costs of CO2
emissions and had results ranging from $3.6 to $68.5.2/tCO2
emission in 2011e2020 prices (Clarkson and Deyes, 2002). In 1996,
the IPCC (Intergovernmental Panel on Climate Change) Working
Group III published a review and reported that the social costs of
CO2 ranged from $1.6 to $43.6/tCO2 in 2000 prices (Guo et al.,
2006). Stern (2007) has reported marginal damage costs of CO2
emissions and a result about $85/tCO2.
Recently, Tol (2011) reviewed previous studies and calculated
the social costs of carbon emissions and found the average cost to
be $31/tCO2. Hope (2011) applied the PAGE09 Model to estimate
the social costs of CO2 emissions and found the average cost of CO2
emissions to be $100/tCO2. Etchart et al. (2012) also reviewed
previous studies and found that the social costs of CO2 emissions
ranged from $5/tCO2 to $200/tCO2.
The broad ranges of estimated results for the social costs of CO2
emissions could be because of the sheer size of the uncertainties of
future climate changes, future socioeconomic variables, particular
ethical parameters adopted in each model, different representations
of the carbon cycle, different estimates of the rate of warming,
etc. (Guo et al., 2006; Tol, 2011) The present authors also found that
the estimated results of social costs rates of CO2 emissions tended
to increase gradually through literature reviews.