The bar chart compares the amount of carbon dioxide emitted by three income groups in 1990 and 2000, whereas the pie chart illustrates each group’s share of the world’s population in 2000. Overall, the middle income group was the largest emitter in 2000, while the low income group produced a negligible share of emissions throughout the period.
In 1990, the high income group released 13 metric tonnes of carbon dioxide, slightly more than the middle income group’s 15 tonnes, which was the largest figure at that time. By 2000, however, the middle income group’s emissions had climbed to 22 tonnes, whereas the high income group’s had fallen marginally to 12 tonnes. Emissions from the low income group remained very small, rising only from 1 tonne to 2 tonnes over the decade.
Although the high income group produced 12 tonnes of emissions in 2000, it accounted for 48% of the world’s population, the largest share of the three groups. By contrast, the low income group made up 18% of the population but emitted only 2 tonnes. The middle income group, representing 34% of people, produced the highest emissions, which suggests that population size and emissions do not move in step.