1.  As we can see in Figure 3.2 which shows the amount of carbon dioxide emissions from the burning of coal, oil, and natural gas from 1860 to 1990, countries across the world have been divided into three groups: The first group includes North America, western Europe and Pacific developed countries.

2.  The third group includes 13 nations and regions while the data of the first and the second group is 174 and 37(1).

3.  Group two includes former USSR and Central & Eastern Europe, which exceeds the first group after 1930.