Environmental Engineering Reference
The World's Proven Fossil Fuel Reserves, Rates of Consumption, and Lifetimes
Rate of Growth (%/y) Lifetime (y)
Fuel Reserves (Q)
1995 Consumption (Q/y)
No Growth with Growth
The amount of methane hydrates at the ocean bottoms and ice caps may range from 1 to
2 E(16) kg. 11 Taking the heating value of methane as 4.76 E(4) Btu/kg, the heating value stored
in methane hydrates could amount to 5-10 E(5) Q, two orders of magnitude larger than proven
gas reserves. However, the amount of gas hydrates is speculative, and no technology exists yet to
recover the methane from gas hydrates laying on the ocean bottom or under ice caps.
Summary of Fossil Reserves
The world's proven fossil fuel reserves are summarized in Table 2.4. Also listed are the lifetimes
of the reserves for the case that 1995 consumption continues without growth into the future and
for the case that the 1987-1997 growth rate continues into the future.
We reviewed the present and historic trends of energy consumption and supply patterns in the
world as a whole, as well as in individual countries—by industrial sector, by end-use, and per
capita. The so-called “developed” countries consume a much larger amount of energy and emit a
much higher rate of CO 2 per capita than the “less developed” countries. However, the converse
is true for energy use per Gross Domestic Product (GDP). The “less developed” countries have
a higher ratio of energy consumption and a higher emission rate of CO 2 per dollar GDP than the
Measured by the available proven fossil energy reserves, and present rate of consumption, coal
may last 250-300 years, oil 65-70 years, and natural gas 85-90 years. Unconventional fossil energy
resources, such as oil shale, tar sands, geopressurized methane, and methane hydrates, may extend
the lifetime of fossil fuels severalfold, but their exploitation will require greatly increased capital
investment and improved technology. The price of the delivered product will be much higher than
is currently paid for these commodities.
The major conclusion is that for the sake of husbanding the fossil fuel reserves, as well as
for the sake of mitigating air pollution and the CO 2 -caused global warming, mankind ought to
conserve these fuels, increase the efficiency of their uses, and shift to nonfossil energy sources.
11 Kvenvolden, K. A., 1988. Chem. Geol. 71, 41.