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Energy is one of the most basic of human needs, not as an end in itself but as a means to numerous ends. We need energy to heat and air-condition our living spaces, to cook food and forge steel, to power engines and for transportation, and most of all to generate electricity for myriad purposes from boiling a kettle to running computer systems. During the past 50 years, global consumption of commercial energy has risen more than fourfold, far outpacing the rise in population. One way or another, all this energy comes from natural resources whether fossil fuels such as coal and oil, living resources such as timber and biomass, nuclear fuel such as uranium, or renewable resources such as flowing water and wind and the power of the sun. A generation ago, there was concern that fossil fuels would run out,
plunging the world into an energy crisis. Today the fear is that their
continued use might be wrecking the global climate by emitting carbon
dioxide (CO2) as we burn carbon-containing fuels. This anxiety is substantially
increased in view of the considerable unmet demand for energy in the developing
world. Energy use is closely tied to health and well-being
low energy users have high infant mortality rates, low literacy rates
and low life expectancies. Worldwide, 2 billion people do not have access
to electricity and use fuelwood or dung for cooking and heating
often destroying their local environments in the process. The challenge
for the 21st century is to develop methods of generating and using energy
that meet the needs of the poor while protecting the planet. There are three global energy trends in relation to demographics.
First and most obviously, as populations grow, energy use increases. Secondly,
as wealth grows, energy use per capita also increases. In the early stages
of industrialization, this is typically accompanied by a decline in the
efficiency with which energy supplies are used, resulting in more pollution
per dollar of output. Indias emissions of CO2 per dollar of GDP
rose by 29 percent between 1980 and 1995; Malaysias rose by 58 percent1.
But the third stage is more optimistic2. Beyond a certain threshold of wealth, which may vary widely between countries, energy efficiency begins to improve. Thereafter, countries with expanding economies and growing personal wealth can, with sensible energy policies, dramatically reduce growth in energy use. They may begin to show sharp reductions in emissions of polluting gases, including greenhouse gases, particularly by shifting to cleaner sources of energy, such as natural gas and renewables.
The world is already slowly starting to wean itself from
the most polluting energy source coal. During the past 50 years,
global coal use has only doubled, while oil use has risen sevenfold and
natural gas use more than tenfold3.
China, the worlds largest user of coal, has recently begun to cut
its consumption despite continued fast economic growth. With similar declines
in many industrialized countries, global coal use may be close to or past
its peak with positive effects on urban air pollution, acid deposition
and the greenhouse effect 4.
Gains in the use of non-fossil fuels have been inconsistent.
Alternative technologies that require large initial capital outlays did
well until around 1990, but have since stalled. World civil nuclear reactor
construction is now just a tenth of 1970s levels both because Western
civil society has turned against nuclear power and because former Soviet
bloc nations cannot afford the investment. Large-scale hydroelectric power
has suffered from a shortage of sites and a growing awareness of its environmental
downside. But smaller-scale renewable energy sources, notably wind and
solar power, have seen double-digit annual growth albeit from a
lower starting point5.
The fast-growing demand for energy in developing countries
offers the opportunity for them to avoid the high-energy and pollution-intensive
development paths of already industrialized countries and leapfrog
to sustainable energy sources. There are many examples of moves around
the world to more sustainable energy policies. Solar power is making inroads
in many parts of rural Africa where urban electricity grids are unlikely
to reach. Wind turbines are whirring on the plains of India, the steppes
of Mongolia, the shores of the North Sea and among the sheep of Patagonia.
Brazil fuels half its vehicles on ethanol made from fermented sugarcane
juice, reducing the countrys CO2 emissions by 18 percent 6.
Many leading figures in the oil business believe that
by the middle of the century the worlds vehicle fleet will run on
hydrogen fuel cells, probably extracted from water using electricity generated
from renewable sources7.
Iceland has plans to complete the task of creating the first hydrogen
economy within its own shores by 2020, using its domestic geothermal
and hydroelectric energy sources to convert its small self-contained vehicle
fleet8.
Most analysts still anticipate fast global rises in
the use of oil and natural gas, and expect CO2 emissions to continue to
rise for many decades yet, as developing countries economies grow.
But the increases may be much less than once feared. In 1997 and 1998,
the global economy grew by 6.8 percent, but CO2 emissions held steady.
The explanation appeared to lie in a combination of reduced coal use and
the rise of economic growth based on new information technologies, which
have lower energy requirements than traditional industries9.
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Copyright AAAS 2000. |