The given chart compares the average amount of carbon dioxide emitted by each person in Great Britain, Sweden, Italy and Portugal over 4 decades from 1967 to 2007.
Overall, the figures for CO2 emissions in the United Kingdom and Sweden witnessed a downward trend whereas the opposite was true for the others. Another noticeable point is that the level of carbon dioxide produced per capita in Britain remained the highest, while Portugal was the least significant contributor of this substance over the period in question.
As regards the United Kingdom, peaking at around 11 metric tonnes in 1967, its CO2 emissions declined steadily over the surveyed years and finally hit the lowest point of 8.5 metric tonnes in 2007. Conversely, the amount of CO2 generation per head in Sweden recorded fluctuations as it went up from 8.5 to around 10 metric tonnes in 1977. This was followed by a plunge of over 3 metric tonnes in the next 10 years before it had gradually reduced to 5.3 metric tonnes by the end of the given period.
Turning to Italy, standing at just over 4 metric tonnes, its CO2 emissions per individual experienced a remarkable rise and reached its peak at around 7.8 metric tonnes in 1997. Subsequently, the figure plateaued over the final decade. Likewise, Portugal started at about 1 metric tonnes prior to a soar in the next 30 years, reaching the highest point of over 5 metric tonnes. From then on, the number nearly levelled off and finished the period at the same point as Sweden.