The line graph illustrates the proportion of four types of fuel (wood, coal, oil and gas) used worldwide between 1800 and 2000.
Overall, there was a clear shift from traditional to modern energy sources. Wood usage declined dramatically over the period, while coal rose to a peak before falling. In contrast, oil and gas became increasingly important in the 20th century.
In 1800, wood was the dominant fuel, accounting for almost 100% of usage. However, its share decreased steadily, dropping to around 50% by the mid-19th century and falling to nearly zero by 2000. Meanwhile, coal usage increased rapidly from 0% in 1800 to approximately 70% in 1900, making it the leading fuel at that time. After reaching its peak, coal consumption gradually declined to about 30% by the end of the period.
Oil and gas, on the other hand, were negligible before 1900. Oil began to rise sharply in the early 20th century and reached roughly 35% by 2000. Similarly, gas showed a steady increase, ending at a level comparable to oil.
In conclusion, the graph highlights a transition from wood to coal, followed by the growing importance of oil and gas in modern energy consumption.
