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CARBON FOOTPRINT CALCULATORS
There are many
calculators on the web to estimate the global warming emissions of you and your
family.
The strength
of the calculators is to give you an approximation of your own emissions, which
may lead you to more urgency in cutting back, and humility about how hard it is
to cut deeply.
Naturally all
calculators have weaknesses. Your airplane flights may be less or more full
than average, so they burned more or less fuel per traveler. If a calculator
measures fossil fuels only, it omits the CO2 emitted while making
everything else you buy, as well as methane from hydroelectric reservoirs
and CO2 from mining and processing nuclear fuel. Most
companies who report CO2 footprints just measure fossil fuel. If a
calculator omits food, it omits the global warming from nitrous oxide released
by fertilizer, and methane from animals' digestion and manure.
Calculators
convert all greenhouse gases (such as methane and nitrous oxide) to the amount
of CO2 which would have the same effect over 100 years. Methane has
its strongest effects quickly, so it would raise the CO2e of hydroelectricity
and meat if we looked at the next 20 years.
Use the best
calculator you can, and know it is only a more or less complete estimate.
TRENDS IN YOUR CO2e
Two British calculators and
our own draft show your trend in CO2e over
time. The trend is very motivating, since it lets you see your
improvements. All three have attractive graphs and easy data entry.
To start, you may want some old electric bills to
get meter readings from the past, and car repair bills to get old mileage readings.
The calculators also ask for airplane trips and other fuels if you have them.
You get an immediate graph of CO2e
by day or by month, as far back as you have records. Keep coming back to add to
your graph.
CO2List.org
has a draft calculator in a spreadsheet. It includes
more forms of transportation than usual, as well as CO2e embedded in products and imports, and
emissions from hydroelectric and nuclear sources. You can enter:
Travel by air, rail, car, bus, bicycle and cruise ship
Meter readings for electricity and gas
Heating oil deliveries
Estimates of meat and eggs
Purchases of other items, in any of 130 currencies, including CO2e
from imports for 24 major importers
Size of the home and of any solar cells, to estimate CO2 used
in their construction
Size of your trees and yard, to see how much CO2 they capture
each year
Choice of metric or pounds/gallons/miles
It gives
colorful graphs of your full CO2e
emissions over time. Tell us
if it works for you, what you like and don't like. This and the Berkeley annual
calculator (below) are the only ones which include your full range of spending.
Berkeley has better detail on sectors, but does not have monthly variation or
CO2 captured by your trees and yard.
For
electricity this calculator uses emissions from the current mix of power
sources in any of 200 countries and territories. It includes exploring,
processing, burning and delivery of fossil fuels, methane from hydroelectric reservoirs,
CO2e from mining and
processing nuclear fuel,
and from making solar or wind collectors.
CarbonDiet Some nice features include
(A) plotting CO2e
each day, though somewhat smoothed with a moving average,
(B) having national data for
(C) letting your car's MPG
change over time (especially as you become a more gas-conscious driver). The CO2List
calculator above also has this feature.
They explain their methods and offer CO2e-saving
suggestions.
They ask you to write down the gallons when you buy
gasoline/petrol; rather than just miles traveled. You will want to estimate
when you forget the number of gallons, or your graph will be incomplete.
CarbonAccount similarly has attractive graphs and easy data
entry. However it averages all data by month, so it is not as detailed as CarbonDiet or CO2List. Also it does not reflect any changes in your miles
per gallon; it estimates gasoline by the odometer readings and assumes a
constant miles per gallon for the life of a car. The site asks for a
Both CarbonDiet and CarbonAccount omit trains, buses, food, and everything else
you buy.
All three use Open Source code, so you can improve
them. CO2List uses Excel. CarbonDiet uses Ruby on
Rails. CarbonAccount uses Django,
Python, SQL.
CALCULATE BEING
GOOD: CO2 CAPTURE
http://greenyard.bayercropscience.com/Bayer/OCTraining.nsf/CarbonCalculator
Bayer (like CO2List above) offers a way to calculate
the carbon captured by lawns and individual trees. Multiply their carbon
results by 44/12 (which is 3.67) to convert pounds of carbon
to pounds of CO2e. It also calculates the greenhouse gases emitted
by mowing and fertilizing. It omits manufacturing the mower, but includes
global warming from nitrous oxide released by the fertilizer. Organic and
synthetic fertilizer release the same amount of nitrous oxide; it depends on
the amount of nitrogen added to the soil, not the source of the nitrogen.
TOTAL CO2 FOR A YEAR
Dozens of other websites do not show CO2e
trends, but simply estimate your total CO2e emissions during a year.
The systems above, which show your improvements, make it easier to stay
motivated.
Calculators from Berkeley and Sweden use full CO2e
factors which include both direct burning of fossil fuel and the rest of the
life cycle, such as refining of petroleum and uranium, methane releases from
gas wells, pipelines and hydroelectric reservoirs, etc. The other calculators
below only include direct burning of fuel. You can compare direct fuel
emissions to the more complete life cycle emissions in the table
below.
Many
calculators ask
broad categories, not actual miles, gallons, destinations, etc. These broad
categories mean you cannot see gradual results from most of your efforts, like
driving better and less, lowering thermostats, fewer purchases, etc.
A good orientation to a few calculators is at http://www.grist.org/article/take-a-number/
which recommends Bonneville Environmental
among the full-year calculators.
The final section of this page
compares some of the calculators' assumptions.
Swedish calculator (in Swedish and English) covers "(1) home and
energy, (2) travel, (3) food and (4) consumables and waste." They ask
broad categories, not actual miles, gallons, destinations, etc., and report
broad categories. The methodology
of the English version says it covers various unspecified ecological effects
besides global warming. Like the CO2List calculator, it says it covers full input-output
effects of CO2 embedded in products, and the extra CO2e
embedded in imports.
Berkeley calculators use US energy and consumption patterns, so they do not
apply to other countries. Like the Swedish and CO2List calculators above,
Berkeley covers input-output
effects, though unlike them it excludes imports.
Berkeley has much
more detail than most. An excellent feature is that it uses your income,
household size, and US surveys to estimate your average purchases from each sector (except government), and the
emissions of that sector. If you want, you can say how much your spending in
each sector is above or below average
for your income and household size, though the feature is hard to use without
knowing what the average is in each
sector. (By contrast, the CO2List calculator uses your actual total spending each month, and each
country's national average CO2e per dollar, adjusted for imports and
exports. Unlike Berkeley it does not adjust for the sectors you use. The
Swedish calculator, like most, only has a few sectors.)
Besides direct fuel, Berkeley includes manufacture
and maintenance of cars, but not construction of roads, planes, or trains,
surprising since the source CO2List uses for those is a Berkeley study. They
include fuel processing and construction of coal/gas/wind/hydro/solar plants
(but omit all if you claim "clean energy"). They do not include
transmission losses, or methane emissions from hydroelectric reservoirs (p.17),
though their source does,
and they seem to omit the significant emissions from processing nuclear fuel.
For food they average EIOLCA.net and CEDA without saying
whether they include methane from animals or N2O from fertilizer.
These are large for red meat, and if omitted may explain why they show only 4.8
gCO2/kilocalorie for red meat (p.24)
compared to 10.8 in the CO2List calculator (from Weber and Mathews
p.3511)
They treat all products as having the same emissions
as US-made products. This probably creates an underestimate of your emissions,
since many products from Canada, China and Mexico have higher emissions than US
products (figures are at bottom of Countries tab of spreadsheet, based on Weber & Matthews
2007, "Embodied Environmental Emissions in US International Trade").
They also have a calculator for businesses, with
much the same information. Like the household calculator it has the great
feature of using broad US surveys to estimate a business' average purchases
from each sector, and the emissions of that sector. It also lets you decide whether
to count employee commutes as part of the business impact; commuting is always
counted in their household calculator.
Note: if you control your computer cookies, you need
to allow cookies from "coolcalifornia.org" as well as
"berkeley.edu."
British calculator
http://calculator.carbonfootprint.com/calculator.aspx
This has much more detail than most. It
covers direct fuel for electricity (any country), gas (all types), oil, coal, wood
pellets, bus, train, taxi. For these it collects actual kwh, miles, gallons,
etc. It also has incomplete estimates for flights, banking, car manufacture,
food and other shopping, collected in broad categories. It ignores road
construction and other government activities, as well as N2O from
fertilizer for growing food. The output is a list of metric tonnes
for each item. They also have a business calculator, and they sell CO2
software and carbon offsets.
French calculator
(in French) asks broad categories of house size, car size, flights, etc., not
actual kilometers, liters, destinations, etc. It does add national
infrastructure. They call it a "test" not a calculator.
British site which compares 12 Ecological and 10 CO2
Footprint Calculators
http://www.esd.rgs.org/link6.html
Ecological Footprint Calculators (12)
1. Environment Agency http://www.environment-agency.gov.uk/fun/370863
2. Earth Day Ecological footprint Quiz http://www.earthday.net/footprint/index.asp#
3. Global Footprints http://www.globalfootprints.org/issues/kidsquiz/kidsquiz1.htm
4.
5. New Scientist http://www.newscientist.com/hottopics/environment/quiz2.jsp
6. Eco Foot http://www.demesta.com/ecofoot/eng/engframe.htm
7. Mountain Equipment Co-op – Ecological Footprint
Calculator http://www.mec.ca/Apps/ecoCalc/ecoCalc.jsp
8. LEAD International http://www.lead.org/leadnet/footprint/food.cfm
9. Ecology Fund http://ecologyfund.com/ecology/res_bestfoot.html
10. Ecological Footprint Lifestyle Calculator http://www.bestfootforward.com/footprintlife.htm
11. The Personal Environmental Impact Calculator http://ans.ep.wisc.edu/~eic/personal.impact.html
12. Redefining Progress http://www.rprogress.org/programs/sustainabilityindicators/ef/Footpdist
Carbon Footprint Calculators (10)
1. Best Foot Forward http://www.bestfootforward.com/carbonlife.htm
2. The National Energy Foundation – Energy to Carbon
Dioxide Converter http://www.natenergy.org.uk/convert.htm
3. Global Action Plan http://www.carboncalculator.org
4. Future Forests http://www.futureforests.com/acatalog/index_world_calculator.asp
5. International Council for Local Environmental
initiatives (ICLEI) – Personal Carbon Dioxide Calculator http://www3.iclei.org/co2/co2calc.htm
6. Centre for Alternative Technology (
7. Safe Climate – Carbon Footprint Calculator http://www.safeclimate.net/individual.php
8. Travel Calculator http://www.travelcalculator.org
9. Choose Climate http://www.chooseclimate.org/flying/mapcalc.html
10. Climate Care http://www.climatecare.org/calculator/index.cfm
US site which
lists about 20 calculators
http://www.medical-assistant.net/emission-calculator
SPECIALIZED
CALCULATORS
FINAL WORDS
|
|
Multipliers in Various Calculators, Compared
to each other and CO2List.org estimates |
Automobile
Gasoline |
Electricity |
Air
Flight, kg CO2 per passenger
kilometer, Economy. Multiply by 3.5 for lb/mile |
High Altitude (Radiative Forcing) Index |
Class
of Seat, Multiplier for Emission, Based on Seat
Sizes |
|
|||||||
|
lb
CO2 / |
kg CO2 per
liter |
lb CO2 per kWh |
kg CO2 per kWh |
204 km, 127 miles1 |
1,001 km, 622 miles |
5,001 km, 3,107 miles |
17,100 km, 10,625 miles2 |
Economy |
Overseas Business |
Overseas First |
|
|||
|
|
Most Complete: Fuel, Vehicle &
Infrastructure, from CO2List.org (methods) (exponential airplane
formula based on data in Chester
2008) |
36.1 incl. manuf. |
4.3 |
1.80 US |
0.80 |
0.88 |
0.36 |
0.29 |
0.46 |
3.9 only cruising altitude |
1.00 |
2.14 |
3.14 |
|
|
Include
Direct Fuel & High Altitude Effects |
Direct Fossil Fuel only, from
CO2List.org (methods) (exponential air, based on data in Chester 2008) |
19.6 |
2.3 |
1.37
US |
0.62 |
0.60 |
0.24 |
0.19 |
0.21 |
2.7 |
1.00 |
2.14 |
3.14 |
|
|
Calculators with Fairly
Precise Data |
|
|||||||||||||
|
(air from CarbonPlanet Ross 2007) |
19.4 |
2.3 |
1.19 |
0.54 |
0.45 |
0.30 |
0.32 |
0.32 |
2.7 |
1.00 |
2.10 |
3.40 |
|
|
|
TheCarbonAccount.com (methods) (air from DEFRA & Atmosfair) |
20.1 |
2.4 |
1.16 |
0.53 |
0.41 |
0.41 |
0.27 |
0.30 |
2.7 |
1.00 |
1.40 |
1.60 |
|
|
|
CoolClimate.Berkeley.edu
(methods)
(adds 26% for
indirect fuel, 1st row uses average; 2nd row uses
categories) |
27.7 incl. manuf. |
3.3 |
1.84 US |
0.22 |
0.28 0.75 |
0.28 0.41 |
0.28 0.28 |
0.28 0.08 |
1.8 |
1.00 |
1.00 |
1.00 |
|
|
|
19.6 |
2.3 |
1.36 US |
0.62 |
0.31 |
0.23 |
0.23 |
0.23 |
2.0 |
1.00 |
1.00 |
1.00 |
|
||
|
20.4 |
2.4 |
1.43 US3 |
0.65 |
|
|
|
|
|
|
|
|
|
||
|
ChooseClimate.org, only 1 flight at a time |
|
|
|
|
1.14 |
0.49 |
0.35 |
0.33 |
3.0 |
1.00 |
1.49 |
|
|
|
|
Atmosfair (methods), only airplanes (fuel calculated from exact route taken) |
|
|
|
|
0.25 |
|
|
0.30 |
3.0 |
1.00 |
1.88 |
2.50 |
|
|
|
The
following use broad averages, not actual kWh, MPG, or flight length, so they
are very imprecise |
|
|||||||||||||
|
Al Gore's Inconvenient Truth (methods) (air from World Resources Institute GHG Mobile) |
19.6 |
2.3 |
1.34 US4 |
0.61 |
0.43 |
0.16 |
0.09 |
0.05 |
1.0 |
1.00 |
1.00 |
1.00 |
|
|
|
(air
from World Resources Institute GHG) |
19.6 |
2.3 |
1.34 US4 |
0.61 |
0.64 |
0.64 |
0.64 |
0.64 |
unknown |
1.00 |
1.00 |
1.00 |
|
|
|
unknown |
|
1.34 US4 |
0.61 |
0.80 |
1.00 |
0.20 |
0.06 |
1.0 |
1.00 |
1.00 |
1.00 |
|
||
|
1Shortest flight shown is 2Longest flight shown is 3US average is shown. EPA uses mix generated in each of 26
eGrid subregions although subregions
share power widely within each of the 5 major grids. 4US average is shown. Calculators use mix generated in
each of 51 states, not mix used in relevant grid (US has only 5 major
power-sharing grids). More comparisons (and graphs)
are in a spreadsheet, at the bottom of
the "Air" tab. |
||||||||||||||
The
calculators are actually misnamed. They do not estimate Carbon; they estimate
CO2-equivalent, which is what you want anyway, to address global warming.
The tradition has always been to call them Carbon calculators.