Air Quality Issues of Electricity Production:
Climate Change

What do we mean by global climate change?

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?

Human health impacts
Global 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.

Extreme weather impacts
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.

Coastal zones 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 century.

Forest devastation
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
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.

References:

The Energy Project, Land and Water Fund of the Rockies, How the West Can Win: A Blueprint for a Clean and Affordable Energy Future (1996).

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).

Additional Information: