Earth’s fossil fuel resources are not distributed evenly. Some regions are well endowed with one or more fossil fuels, whereas other regions have little. The uneven distribution of fossil fuels partly reflects how fossil fuels form.
Coal formed in tropical locations, in lush, swampy areas rich in plants. Thanks to the slow movement of Earth’s drifting continents, the tropical swamps of 250 million years ago relocated to the mid-latitudes. As a result, today’s main reserves of coal are in mid-latitude countries rather than in the tropics. China produces nearly one-half of the world’s coal, other developing countries one-fourth, and developed countries (primarily the United States) the remaining one-fourth.
Coal Production
China is the world’s leading producer of coal, followed by the United States.
Petroleum formed millions of years ago from residue deposited on the seafloor. Some still lies beneath such seas as the Persian Gulf and the North Sea, but other reserves are located beneath land that was under water millions of years ago. Russia and Saudi Arabia together supply one-fourth of the world’s petroleum, other developing countries (primarily in Southwest and Central Asia) one-half, and developed countries (primarily the United States) the remaining one-fourth.
Petroleum Production
Russia, Saudi Arabia, and the United States are the leading producers of petroleum.
Like petroleum, natural gas formed millions of years ago from sediment deposited on the seafloor. One-third of natural gas production is supplied by Russia and Southwest Asia, one-third by other developing regions, and one-third by developed countries (primarily the United States).
Natural Gas Production
The United States and Russia are the leading producers of natural gas.
Each Map/graph use the same units (quad BTUs), as well as the same classes. Quad is short for quadrillion (1 quadrillion = 1,000,000,000,000,000), and BTU is short for British thermal unit. One quad BTU equals approximately 8 billion U.S. gallons of gasoline.
The supply of energy remaining in deposits that have been discovered is called a proven reserve. Proven reserves can be measured with reasonable accuracy:
Coal. World reserves are approximately 1 quadrillion metric tons (23 million quad BTUs). At current demand, proven coal reserves would last 110 years. The United States, Russia, China, and Australia have 70 percent of the world’s proven coal reserves.
Natural gas. World reserves are approximately 7,000 trillion cubic meters (7,200 quad BTUs). At current demand, proven natural gas reserves would last 54 years. Iran, Russia, and Qatar together have one-half of the world’s proven reserves.
Petroleum. World reserves are approximately 1.7 trillion barrels (9,000 quad BTUs). At current demand, proven petroleum reserves would last 43 years. Venezuela and Saudi Arabia are the two leading locations of proven petroleum reserves.
Proven Reserves
(a) Coal, (b) Natural gas, (c) Petroleum
How does the distribution of proven reserves differ from the distribution of current production?