The Carbon Cycle and
Mankind
We
have seen that plants sequester large sums of carbon in themselves. They
are able to do this since, on average, photosynthesis produces more sugar than
what is need by the plant during its respiration phase. As long as the
plant is alive, it will continue to take carbon dioxide out of the air.
However, we also found that a plant will return all of that carbon dioxide back
into the atmosphere after it dies if the wood is burned or allowed to decay.
In
this week’s lab, we are going to investigate what effect mankind has on the
carbon cycle. In particular, we are going to estimate the amount of
carbon dioxide that each one of us is responsible for emitting each year.
This analysis is going to study only those day-to-day activities that emit
carbon dioxide, and not look at the unique events that we have that also emit
carbon dioxide (like bulldozing a forest and grinding up the
trees). Our modern way of life relies heavily on the emission of
carbon dioxide. When we think about this, we often limit ourselves to the
use of automobiles and trucks and a few industrial processes. We
understand that when we burn the gasoline in our engines, we are oxidizing the
fuel and creating carbon dioxide. However, there are other activities in
our life that also emit CO2, even though we do not see the
oxidation. When we use electricity, we are also emitting carbon dioxide.
The majority of the electricity created in the state of Georgia is derived from
burning natural gas or coal. We also emit CO2 when we heat and
cool our homes, since this requires the use of electricity or the burning of
natural gas, propane, heating oil, or wood. Even our creation of garbage
releases carbon dioxide in the environment. If this garbage is put into a
landfill, it decays and puts CO2 back into the atmosphere. If
it is recycled, energy of some form will be used to accomplish this, emitting
CO2 in the process.
Calculating Your
Emissions of Carbon Dioxide
Overview
So
how much carbon dioxide is emitted to the atmosphere through your daily
activities? To answer this question, you will use an online Household Carbon
Footprint Calculator developed by the U.S. Environmental Protection Agency
(EPA). The calculator sums the carbon dioxide produced by your driving,
electricity use, and waste disposal, and provides you with an estimate of your
annual carbon dioxide emissions. The calculator then allow
s you to see how
changes in your lifestyle could reduce your carbon dioxide emissions.
Before
you begin
Americans
tend to contribute a lot of carbon dioxide through driving, so it is therefore
vitally important that you know your vehicle’s gas mileage. To assist you, the
US Department of Energy and EPA have created a web site that allows users to
look up the gas mileage for any vehicle made from 1985 through the present.
Your first step is to determine your vehicle’s gas mileage from this site.
After entering the year, make, and model of your vehicle, you will be provided
with its city and highway gas mileage. For simplicity’s sake, assume that half
of the miles you drive are highway travel, and the other half are city/suburban
travel unless your mileage patterns differ. To obtain a single value for gas
mileage, simply use the average of the city and highway mileages listed.
Vehicle Fuel Economy
Resources
Online database
of vehicle fuel efficiencies
U.S.
Department of Energy
http://www.fueleconomy.gov/Complete
the Household Carbon Footprint Calculator
and enter the appropriate information in the Activity sheet. The use of the
calculator is largely self-explanatory, so detailed directions will not be
provided. A few comments, though:
(1.)
In the Transportation section, make sure you select the appropriate time frame
(week or year) for your entered mileage.
(2.) In the Home Energy section, enter the average of your summer and winter
electric and gas bills.
Household
Carbon Footprint Calculator
Allows
users to analyze their emissions of CO2 and learn ways to reduce
them
U.S. Environmental
Protection Agency
https://www3.epa.gov/carbon-footprint-calculator/
*Note: If you have trouble
loading the page, press the reload button or try a different browser.
Let me know if you have any problems with it.
The
activity sheet will ask you to enter and analyze values from this first run of
the calculator, and then use the subsequent section of the calculator to
investigate how you can reduce your carbon dioxide emissions. A portion of the
activity asks you to consider the change from a conventional vehicle to a more
efficient gasoline/electric powered “hybrid” vehicle. To learn more
about such vehicles, visit the link below.
Hybrid
Electric Vehicle Program
Information
about hybrid vehicles
U.S.
Department of Energy’s Office of Transportation Technologies
https://www.afdc.energy.gov/vehicles/electric_basics_hev.html