The analysis of global energy and environmental issues have often been hampered by the lack of a comprehensive energy-economy wide-global data set. Recently the Center for Global Trade Analysis at Purdue University has produced a special version of the GTAP data base called GTAP 4-E together with an energy price and volume data set. This paper utilises these data set in some illustrative experiments. The experiments involve simulating the effects of the cutting back on the world CO2 emission level by some 25 per cent in a comparative static framework. The results show that using the standard GTAP version 4 data base and the special purpose GTAP 4-E data base can produce significantly different results.