Air Quality Issues of Electricity Production:
What do we mean by global
The term "global
climate change" usually refers to changes to the earth's climate brought
about by a wide array of human activities. Because of predictions of a
steady rise in average world-wide temperatures, global climate change
is sometimes referred to as "global warming." Regardless of which term
is used, different methods of electricity production can impact the earth's
climate in ways that raise extraordinary environmental issues.
There is increasing
scientific evidence showing that human enterprises -- especially burning
fossil fuels such as coal, oil and natural gas - are altering the earth's
climate. Burning fossil fuels releases carbon that has previously been
locked up in coal, oil and natural gas for millions of years. The carbon
in these fossil fuels is transformed into carbon dioxide (CO2), the predominant
gas contributing to the "greenhouse effect," during the combustion process.
The greenhouse effect
allows energy from the sun to pass through the earth's atmosphere and
then traps some of that energy in the form of heat. This process has kept
global temperatures on earth relatively stable - currently averaging 60
degrees Fahrenheit (33 degrees Celsius) -- and livable for human populations.
Nonetheless, jumps in emissions of CO2 and other gases, such as methane,
traced to fossil fuel burning and other human endeavors, boost heat trapping
processes in the atmosphere, gradually raising average world-wide temperatures.
The US Environmental
Protection Agency observes that the surface temperature this century is
as warm or warmer than any other century since at least 1400 AD. The ten
warmest years on record have all occurred since 1980. The warmest year
so far on record was 1998.
The release of vast
stores of fossilized carbon threaten to raise average global temperatures
at an accelerated pace. Scientists have observed that the earth's surface
warmed by approximately 1 degree Fahrenheit during the 20th century. The
Intergovernmental Panel on Climate Change (IPCC), the scientific advisory
body created by the United Nations to analyze the science of global climate
change, reports that unless the world takes drastic and immediate steps
to reduce the emissions of gases that are creating a magnified greenhouse
effect, global temperatures could rise another 1.6 to 6.3 degrees Fahrenheit
by the year 2100. This would represent the fastest rate of warming since
the end of the last ice age more than 10,000 years ago.
It is difficult to
know precisely how quickly the earth's temperature will jump since human
influences mix with natural events that may slow or accelerate these long-term
trends. It is quite possible, however, to identify actions to reduce causes
of climate change, thereby reducing the intense risks associated with
such a hot planet. Energy-related ventures account for about 86 percent
of all greenhouse gas emissions linked to human activities. Since power
plants, and related electricity generation operations, produce 36 percent
of total US greenhouse gas emissions, reductions in this sector can play
a major role in slowing global climate change.
What are the consequences
of global climate change?
warming poses a major threat to human health by way of increased infectious
diseases. Increasing temperatures nurture the spread of disease-carrying
mosquitoes and rodents. IPCC scientists project that as warmer temperatures
spread north and south from the tropics and to higher elevations, malaria-carrying
mosquitoes will spread with them, significantly extending the exposure
of the world's people to malaria. Scientists at the Harvard Medical School
have linked recent US outbreaks of dengue (breakbone) fever, malaria,
hantavirus and other diseases to global climate change.
The IPCC identifies more frequent and more severe heat waves as a potential
lethal effect of global warming. Some segments of the population, especially
people in a weakened state of health, are vulnerable to heat stress. Recall
the deadly 1995 Chicago heat wave that stretched on for days and killed
669 people during the summer of 1995. Though imprecise in their predictions,
global weather models indicate that extreme weather events are more likely
to occur from increases in global average temperatures. The ocean temperature
shifts, especially the El Nino and La Nina events in the southern Pacific
Ocean, may occur more rapidly and more often, generating major changes
in global weather patterns.
and small island flooding
As global temperatures rise, sea levels will also rise. The seawater expands
as it warms. Water previously bound to mountain and polar glaciers melts
and flow into the world's seas. Much of the world's population, especially
the poorer people of the world, live at or close to sea level, areas vulnerable
to the lethal combination of rising sea level and increasingly severe
ocean storms. The rising water table along coastlines could also encourage
the release of pathogens into septic systems and waterways. More than
half the world's people live within 35 miles of an ocean or sea. Areas
at risk include developed coastal cities, towns and resort areas, saltwater
marshes, coastal wetlands, sandy beaches, coral reefs, coral atolls, and
river deltas. Sea levels have already risen 4 to 10 inches over the last
Forest ecosystems evolve slowly in response to gradual natural climate
cycles. The rapid pace of global climate change resulting from combustion
of fossil fuels and other industrial and agricultural activities disrupts
such gradual adjustments. Many tree species may be unable to survive at
their present sites due to higher temperatures. Increased drought, more
pests and disease attacks, and higher frequency of forest fires, are all
projected to occur at spots throughout the globe. The IPCC report states
that "averaged over all zones, the [global] models predict that 33 percent
of the currently forested area could be affected . . ."
Agriculture depends on rainfall, which impacts how to manage crop production,
the types of seeds planted, and investments in irrigation systems. Changing
weather patterns associated with changing global climate patterns pose
major challenges for the farmers, small and large, who feed the world's
growing population. Just as forest ecosystems face the stress of loss
of traditional habitat, so will the world's farming community.
How does electric power production affect the global climate?
The generation of
electricity is the single largest source of CO2 emissions in the United
States. The combustion of fossil fuels such as coal is the primary source
of these air emissions. Coal supplies 57 percent of the total energy harnessed
to generate electricity (and approximately 86 percent of all coal consumed
in the United States is used for electricity generation). Burning coal
produces far more CO2 than oil or natural gas. Reducing reliance upon
coal combustion has to be the cornerstone of any credible global climate
change prevention plan.
Some methods of electricity
production produce no or few CO2 emissions - solar, wind, geothermal,
hydropower, and nuclear systems particularly. Power plants fueled by wood,
agricultural crop wastes, livestock wastes, and methane collected from
municipal landfills release CO2 emissions but may contribute little to
global climate change since they also can prevent even greater releases
of both CO2 and methane.
Biomass fuels that
depend on forest resources must be evaluated carefully since the stock
of forests world wide represent a storehouse for CO2. If forests are harvested
for fuel to generate electricity, and are not replaced, global climate
change could be accelerated. If electricity generators use forest or other
plant stocks that are being regrown in a closed cycle of growth, combustion
and regrowth, the CO2 emissions may be offset by plant and animal growth
that withdraws CO2 from the atmosphere. Closed cycle systems such as this
one are carbon "neutral." These neutral biomass systems represent progress
since they displace the fossil fuel combustion that would otherwise increase
the CO2 linked to rising temperatures.
On a pound for pound
basis, methane has over 20 times the heat trapping capacity of CO2. Power
plants that capture methane -- or prevent methane releases -- are therefore
extremely beneficial when it comes to slowing global climate change. Methane
is produced by the natural decay of organic materials underground or in
other spots lacking oxygen. Municipal landfills, large piles of animal
wastes, and other sites where plant wastes decay without exposure to the
air, generate large volumes of methane that escape into the atmosphere.
Natural gas is simply methane produced by the decay of plant and animal
matter that is captured beneath the earth's surface over millions of years.
It is therefore important to stop methane production or capture and burn
it so that it does not escape into the atmosphere, where it may accelerate
global climate change.
How can consumer
electricity choice address global climate change?
The impact of climate
change may be pervasive. Still, it is quite difficult to predict specific
outcomes. The potential impacts cited are but a sample of a much longer
and even more sobering litany in the scientific literature. Most of the
steps consumers can take to reduce levels of greenhouse gases will have
beneficial effects on public health and the environment -- regardless
of the actual degree of future changes in global climates.
The new opportunity
to choose among electricity suppliers in competitive retail markets allows
all of us to select power sources that generate the fewest CO2 and methane
emissions when they generate electricity.
If concerned about
global climate change, seek out companies and products that do not rely
on coal for electricity generation. Renewable energy -- wind and solar
fuels in particular -- release negligible amounts of gases contributing
to climate change, even when the manufacturing of the hardware is considered.
Buying electricity from landfill gas power plants is also a good response
to the global climate change threat since methane is not allowed to seep
into the atmosphere. Because fossil fuels still remain a major part of
most energy diets in the short term, consumers can encourage their service
providers to seek out fossil fuels with the lowest carbon content, beginning
with natural gas power plants and then a ranking of oil-fired facilities.
The Energy Project, Land and Water Fund of the Rockies, How
the West Can Win: A Blueprint for a Clean and Affordable Energy Future
Empire State Electric Energy Research Corporation (ESEERCO), New York
State Environmental Externalities Cost Study Vol. 1 (1995).
Pace University Center for Environmental Legal Studies, Environmental
Costs of Electricity (1990).
An Inconvenient Truth - the book and the movie: A fan-based website providing information and
resources related to climate change and the acclaimed climate crisis movie “An Inconvenient Truth”
Brookings Institute: "U.S. Climate Policy: Toward a Sensible Center"
Climate HotMap http://www.climatehotmap.org/
Environmental Protection Agency's Global Warming site
Natural Resources Defense Council:
Pace's Global Warming Central
http://www.paceenergyproject.org then click "Affiliated Sites"
UNEP/WMO Intergovernmental Panel On Climate Change http://www.ipcc.ch/
Union of Concerned Scientists - USA: Global Warming
World Resources Institute: Climate Change