ENERGY AND CLIMATE CHANGE

Global climate change is an enormous problem that needs our urgent attention. A January 2004 study from a team of conservation biologists based at the University of Leeds, Britain, concluded that by 2050, if temperatures continue to increase as forecast, between 15% and 37% of all land-based animals and plants will become extinct; around one million species.

Eighty-two percent of greenhouse gas emissions are from the fossil fuels we burn to generate electricity and power cars. The remaining emissions are from methane from waste in our landfills, raising livestock, natural gas pipelines, coal, industrial chemicals and other sources.

About 2,700 pounds of carbon per person per year (18% of total emissions) come from operating our homes, and most of that is from the energy used to power electrical appliances.

Individuals can affect the emissions of about 4,800 pounds of carbon equivalent, or nearly 32% of the total emissions per person, by the choices made in three areas of day-to-day life.

• Electricity we use in our homes
• Waste we produce
• Mode of personal transportation

The other 68% of emissions are affected more by the types of industries in the U.S., the types of offices we use, how our food is grown, and other factors.

According to the US National Academy of Sciences, the Earth’s surface temperature has risen by about 1 degree Fahrenheit in the past century, and the warming’s gotten faster in the last two decades. There is new and stronger evidence that most of the warming over the last 50 years is linked directly to human activities.

Human activities have altered the chemical composition of the atmosphere through the buildup of greenhouse gases – primarily carbon dioxide, methane, and nitrous oxide. The heat-trapping property of these gases is undisputed although uncertainties exist about exactly how earth’s climate responds to them.

Energy from the sun drives the earth’s weather and climate, and heats the earth’s surface; in turn, the earth radiates energy back into space. Atmospheric greenhouse gases (water vapor, carbon dioxide, and other gases) trap the outgoing energy, and retain heat like the glass panels of a greenhouse.

Without this natural “greenhouse effect,” temperatures would be much lower than they are now, and life as known today would not be possible. Because of greenhouse gases, the earth’s average temperature is a more hospitable 60°F. However, problems may arise when the atmospheric concentration of greenhouse gases increases.

Since the beginning of the industrial revolution in the late 18th Century, atmospheric concentrations of carbon dioxide have increased nearly 30%, methane concentrations have more than doubled, and nitrous oxide concentrations have risen by about 15%. These increases have enhanced the heat-trapping capability of the earth’s atmosphere.

Why are greenhouse gas concentrations increasing? Scientists believe the combustion of fossil fuels and other human activities are the primary reason for the increased concentration of carbon dioxide. Plant respiration and the decomposition of organic matter release more than 10 times the CO2 released by human activities; but these releases have generally been in balance during the centuries leading up to the industrial revolution with carbon dioxide absorbed by terrestrial vegetation and the oceans.

What has changed in the last few hundred years is the additional release of carbon dioxide by human activities. Fossil fuels burned to run cars and trucks, heat homes and businesses, and power factories are responsible for about 98% of U.S. carbon dioxide emissions, 24% of methane emissions, and 18% of nitrous oxide emissions. Increased agriculture, deforestation, landfills, industrial production, and mining also contribute a significant share of emissions. The United States emits about one-fifth of total global greenhouse gases.

If we continue on like we are today, by 2100, in the absence of emissions control policies, carbon dioxide concentrations are projected to be 30-150% higher than today’s levels.

(Special thanks to the US Environmental Protection Agency for this excellent, clear and concise overview of climate change.)

 

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