Assignment
Carbon Footprints
Name__Lachniet__
1) See Figure 1.1a at the back of the assignment (from IPCC)
a) What is the 2004 annual global release of carbon (CO2-eq) to the atmosphere, in Gigatons? The "CO2-eq"
means the equivalent amount of CO2 if all other GHGs are expressed in terms of CO2 forcing only.
About 48 GtC
b) From Figure TS 1.4a (back of exercise), what is the current USA/Canada annual per capita release of
carbon (as tons CO2-eq)?
About 26 tons of carbon per capita
2) How does the United States rank in terms of 'carbon intensity', the amount of emissions per capita,
relative to other countries?
The United States (and Canada) rank #1 in the highest 'carbon intensity' per capita, relative to other
countries.
3) Use the carbon footprint calculator at 1) http://www.carbonfootprint.com/calculator.aspx, Use 2011 for
the year. You will need an estimate of your energy use from your utility bills. Use averages for all of 2011 if
you have them; if not, do your best to estimate usage based on your last utility bill. Use the # of people
living in your house.
a) What is your carbon footprint, in metric tons of CO2 per year?
House
=
0.28 metric tons
Flights
=
6.86 metric tons (5 roundtrip LAS-New York)
Car
=
2.88 metric tons (11,000 miles/year @ 38 mpg average)
Secondary
=
5.49 metric tons
Other
=
Total
=
15.51 metric tons
b) How many total pounds is this? (Multiply the answer in tons by 2240 pounds/ton).
15.51 metric tons = 34,742 pounds
c) Using the average per-capita carbon footprint from 2), is your footprint larger or smaller than the National
Average? By how much?
My 15.51 metric ton carbon footprint is considerably lower than the U.S. average of 26 tons of CO2 from the
plot. According to the website, the average U.S. carbon footprint is 20.40 metric tons, so I am still well below
the average according to the web site. But my average is greater than the average for other industrial
nations (11 metric tons), which is largely due to my large number of flights with air travel, versus rail travel,
and my larger miles driven in a personal vehicle.
d) From the list in a), what are your two biggest sources of carbon emissions?
Flights and "Secondary", which just means activities related to living
4) Now, use the carbon footprint calculator of the Environmental Protection Agency
(http://www.epa.gov/climatechange/emissions/ind_calculator.html), which estimates Total Household
Emissions. What is your carbon footprint (in pounds of CO 2 per year)?
25,942 pounds per year for the household of two members, or 12,971 pounds each.
5) From the EPA website, what would reduce your carbon output more, lowering your thermostat setting by
5°F on cold winter nights, or buying a new car that get 8 miles per gallon more than our current car? Show
values for both actions. By how much?
Reduction for lowering thermostat by 5ºF = 2% reduction, or 568 pounds of CO2 per year.
Reduction for purchasing a car that is 8 mpg more efficient = 4% reduction, or 1028 pounds of CO2 per year.
6) If you took all of the possible actions from the EPA website to reduce emissions, by how much (in %) would
you decrease your emissions?
Turn down thermostat by 5 degrees = 568 pounds saved (-2%); turn up thermostat during summer by 5 º =
505 pounds saved (-2%); enable sleep feature on monitor = 123 pounds saved (-0%); wash in cold water
instead of hot = 139 pounds saved (-1%); use a drying rack = 470 pounds saved (-2%); use 10% 'green'
electricity = 801 pounds saved (-3%); replace 15 light bulbs with Energy Star lights = 1503 pounds saved (6%); replace refrigerator with Energy Star = 600 pounds saved (-2%); replace furnace with Energy Star = 3011
pounds saved (-12%); replace single pane windows with Energy Star = 2952 pounds saved (-11%).
Total in % = 2+2+1+2+3+6+2+12+11 = 41%
Total in pounds = 568+505+123+139+470+801+1503+600+3011+2952 = 10,672 pounds
7) See the website http://www.fueleconomy.gov/feg/why.shtml.
a) How many pounds of CO2 is produced by burning a gallon of gas?
Each gallon of gasoline produces 20 pounds of CO2.
b) From the website, what car do you drive, and what is the average carbon footprint of your car, in
tons/year? (if you don't have one, choose one that you would buy if you could).
I drive a 2011 Volkswagen Jetta Sportwagen TDI, which is a diesel. The average carbon footprint of my
vehicle is about 4.6 metric tons per year. Really, I get better gas mileage (38 mpg) than on the website, and I
drive less, so my true footprint is probably closer to 4.0 metric tons per year.
c) How many miles per year (approximately) do you drive it? A typical amount is ca. 15,000 miles/year for
the United States.
In 2011, a typical year, I put on 11,000 miles.
d) How many gallons of fuel do you burn per year (divide miles/yr by average or combined mpg).
Driving 11,000 miles per year, divided by 38 miles per gallon = 289 gallons of gas.
d) How many pounds of CO2 is emitted from this consumption?
289 gallons of gas x 20 pounds per gallon = 5,789 pounds per year.
e) How many tons of CO2 is it? (divide by 2240 to convert from pounds to tons)
5,789 pounds per year divided by 2240 pounds/ton = 2.58 tons per year.
A useful way to look at fuel consumption is using gallons/mile, instead of miles/gallon. Even better is to
calculate the number of gallons that are required to drive 10,000 miles/year (typical for what most Americans
drive). With your car, or the car you would buy if you had the choice (reasonably speaking!), how many gallons
of fuel would your vehicle burn to drive 10,000 miles?
10,000 miles at 38 miles/gallon = 263 gallons.
8) At a price of $3.50/gallon for gas and $3.90/gallon for diesel, how much money does it take to drive your
car 10,000 miles?
236 gallons times $3.90/gallon = $1026 per year.
9) Now, assume that you were going to buy a new car, either the same model as you currently have for the
most recent year, or a Toyota Prius, which is a hybrid gasoline/electric car with high gas mileage. The Prius
uses an internal combustion engine plus and electrical battery to provide supplemental power. The battery
is recharged by the energy coming from harnessing kinetic energy from braking and other sources (it is not
a plug-in electrical car, which have “hidden” emissions from powerplant electricity supply).
What is the price difference between the Prius and the price of your current or desired vehicle? You can find
the price of a new car on www.cars.com, and use $35,000 for the Prius.
Price of a Toyota Prius:
$_35,000______________
Newest model of your car:
$_29,000_______________
Cost/Savings of a Prius:
$_6,000________________
10) How many gallons of gas would the Prius use for 10,000 miles driven?
10,000 miles at 50 miles/gallon = 200 gallons per year.
11) How much would it cost to drive the Prius for 10,000 miles?
200 gallons per year x $3.50 gallon = $700 per year.
12) How many gallons of gas, and dollars, would be saved over those 10,000 miles compared to your current
car?
In my case, by switching from a VW Jetta TDI at $1026/year to a Prius at $700/year, I would save $326/year
in fuel costs.
13) If the Prius is more expensive than your current car, how many years would it take to ‘break even’ in terms
of added car cost versus saving from fuel efficiency? Assume that you would own the Prius for 10 years.
Does it make sense for you to buy a Prius?
At a savings of only $326/year, it would take me 18.4 years to 'break even' on the price. Thus, it doesn't
make sense in pure economic terms to switch to a Prius. Considering that I don't like the styling or
practicality of the Prius, it is not worth it to change cars.
in GtC
Note: The width of each bar represents the number of people in each region, and the height
of each bar is the per capita CO2 emissions. Narrow and Tall = few people with high
emissions; broad and short = lots of people with small emissions.