The line graph illustrates the level of carbon-di-oxide emitted by United Kingdom, Sweden, Italy and Portugal from the year 1967 to 2007, quantified in metric tonnes.
It is evident from the data that United Kingdom has contributed to the highest CO2 emission initially, throughout the 40 year period. Portugal and Sweden started with different rates of pollution and ended up emitting the same amount. Italy had a positive trend throughout.
The maximum carbon-di-oxide output was by United Kingdom in the year 1967, it was around 11 metric tonnes and remained the same for 10 years , later a slight decline of 1 metric ton is observed in the year 1987, gradually it reduced to 9 metric tonnes by 2007. However, Portugal stood at 1 metric ton in 1967, which increased steadily to around 3 metric tonnes in 1987, after which there was a rapid rise to more than 5 metric tonnes 1997, that remained constant upto the year 2007.
Sweden, on the other hand exhibited fluctuations, in 1967 the level was almost 9 metric tonnes which crossed 10 metric tonnes in 1977 and faced a severe fall in 1987 to 7 metric tonnes and decreased further above 5 metric tonnes. Conversely, Italy showed a positive trend, in 1967 it accounted for only about 4 to 5 metric tonnes ,which rose to around 7.8 metric tonnes by the end of 2007. Ultimately, the rate of pollution decreased over the mentioned time period indicating a step towards a helathier nation.