The bar chart compares carbon dioxide emissions among three income groups in 1990 and 2000, while the pie chart illustrates the proportion of the global population belonging to each group in 2000.
Overall, emissions from the middle-income group increased substantially, whereas those from the high-income group declined slightly. Notably, although the high-income group represented the largest share of the world’s population, the middle-income group recorded the highest emissions in 2000.
In 1990, the high-income group emitted 13 metric tonnes of carbon dioxide, compared with 15 tonnes for the middle-income group. Over the following decade, emissions from the latter rose sharply to 22 tonnes, making it the largest emitter among the three groups. By contrast, the figure for the high-income group fell marginally to 12 tonnes. Although the low-income group remained the smallest emitter, its emissions doubled from 1 to 2 tonnes.
Turning to population distribution, high-income countries accounted for 48% of the world’s population, followed by middle-income countries at 34%. The low-income group represented the remaining 18%. Despite comprising a smaller proportion of the population, the middle-income group emitted considerably more carbon dioxide than the high-income group in 2000.