Green Basics: Carbon Footprint
by Collin Dunn, Corvallis, OR, USA on 02.14.08
In addition to metrics like ecological footprint, each of us (and each of the products and services we use and consume every day) has a carbon footprint; it's a way to measure the relative impact of our actions -- as individuals, as businesses, communities and countries, as we eat, work, travel, play, etc. -- in terms of the contribution made to global climate change. Measured in carbon emissions (usually in pounds, tons or kilograms), it's become an increasingly useful and popular tool to help contextualize global warming in our daily routines and lives.
A carbon footprint is the total amount of carbon dioxide (CO2) and other greenhouse gases emitted over the full life cycle of a product or service, and everything has one, from the computer you used to find this article to the next meal you eat (and the one after that, and after that, and so on...) to the shoe that will leave a physical footprint on the ground the next time you walk outside. But that's only part of the story.
First of all, carbon footprints can be calculated in one of two ways: using a Life Cycle Assessment (LCA) method (more accurate and specific), or it can be restricted to the immediately attributable emissions from energy use of fossil fuels (more general). To use your car's carbon footprint as an example: the first method would take into account all carbon emissions required to build the car (including all the metal, plastic, glass and other materials), drive the car and dispose of the car; the second would account only for the fossil fuels that resulted from building, driving and disposing of it.
Click the map for country-by-country emissions data.
Further, there's more than one way to run the numbers, depending on how they're going to be used. Top-down calculations, like those done in the world map above and the US state map below, that calculate per capita carbon footprints, take total emissions from a country (or other high-level group, organization, etc.) and divide these emissions among the residents or otherwise applicable group. Bottom-up calculations, like with your car's carbon emissions from the example above, sum attributable carbon emissions from individual actions.
Okay, so everything has a carbon footprint, and each can be measured a couple different ways, but it's not just a matter of carbon dioxide, though that is the most common of greenhouse gases (GHGs) other than water vapor; other GHGs include (but aren't limited to) methane, ozone, nitrous oxide, sulfur hexafluoride, hydrofluorocarbons, perfluorocarbons and chlorofluorocarbons (see the IPCC list of greenhouse gases for a more thorough list). Given this, still, most carbon footprint calculations include all applicable gases, as they all contribute to the greenhouse effect and our persistently warming globe.
Though a fairly complex calculation, with many variables that are different for each person, carbon footprint calculations generally include energy used to power our homes and transport, including travel by car, airplane, rail and other public transport, as well as all the consumables we use on a regular (and irregular) basis; many of the individual factors above can be calculated separately (e.g. an individual carbon footprint for your home, travel, food, etc.). Once you understand what goes in to your carbon footprint, and, probably more importantly, what your carbon footprint is, you can start reducing it; indeed, for as many ways as there are to create a carbon footprint, there are ways to reduce it.
Increasing the efficiency of our energy use, reducing our energy use and changing a few habits (like eating less meat, eating more local food, not traveling by airplane as much) are some of the quick, easy ways to cut back on the size our individual carbon footprints. After increasing efficiency and reducing use, carbon offsets are also an increasingly popular (and increasingly controversial) way to help mitigate our carbon footprints -- see TreeHugger's How to Green Your Carbon Offsets guide for more on that. But the point remains: there are many, many ways to reduce and even eliminate your carbon footprint; most every article you'll read on TreeHugger will be related to carbon footprints and emissions, though some more directly than others.
Photo credit: glamhag
Moving forward, we expect to see more and more information about the carbon footprints of the things we encounter and use every day; carbon labeling for produce is catching on the UK, and we've seen carbon footprint measurements for everything from cheeseburgers to Christmas, and sushi to Shaq. Want more? Type 'carbon footprint' into our search engine, above, on the right, and go nuts.
Ready to find out what your carbon footprint is? There are a handful of calculators out there; try The Nature Conservancy's Carbon Footprint Calculator and the calculator at ClimateCrisis.net (yep, the site for An Inconvenient Truth) for starters.
Quench your thirst for more green knowledge with our Green Basics column, which appears on TreeHugger on Thursdays.
Just want to give a thumbs up to this entry. Obviously we can't deny the problem of climate change and the value of understanding carbon footprints for individuals, businesses, events, and products. Zerofootprint (http://www.zerofootprint.net) provides another great tool for calculating one's carbon footprint and planning ways to reduce it (full disclosure, I work at Zerofootprint).
Nice post and a good summary. At Carbon Planet (I am founder and Executive Director) we have a global team of engineers (mostly chemical engineers, but others too) and scientists who perform carbon emissions audits that comply with ISO14064-1 (and the WCSBD's GHG Protocol Corporate Accounting and Reporting Standard). It's not always necessary to perform full LCA for companies that don't manufacture products. We've found that many companies simply can not afford the extra expense of a full LCA and it really limits the number of companies able to address their carbon footprint to demand that they all conduct LCA.
This is essentially a mid-way point between the options you cite in your story. We only tend to perform LCA on specific products and services, and use the above mentioned standards for assessing the impact of the general administration of a business.
For consumer retail customers we simply take the published national emissions figures and divide by the total population to get an average emissions per person figure. In Australia that's around 28 tonnes per person. In the USA around 24 tonnes. In the UK around 11 tonnes. In China and India around 1 tonne.
For calculation of flight emissions we have a very detailed FEC that incorporates the so-called "radiative forcing index" which accounts for the fact that the emissions do more harm when released at high altitude. and we distinguish between economy class, business class and first class travel. This is all explained in some detail in a PDF document we produced at http://www.carbonplanet.com/downloads/ghg_emission_factors_for_flights.pdf
See also http://flights.carbonplanet.com for more on this.
Cheers
Dave Sag
http://www.carbonplanet.com
For those who enjoy shopping online but worry about the resulting contributions to global warming, here's a new way to reduce your carbon footprint: www.EarthMoment.com. It's a portal to other online shopping sites, and they make a donation to carbon offsets for every purchase you make. (In the interest of full disclosure, I'm an editor at Mother Earth News magazine, and EarthMoment is brought to you by our publisher.)
This is a great post, simple and straightforward. This entry brings that good old buzzword a whole new meaning and dimension.
All the food we eat and the products we buy produce a carbon footprint. The distribution of these materials from manufacturing to distribution to home is heavily rooted in the trucking industry. We just launched their LoneStar truck which is a significant step towards a more fuel efficient future in the trucking industry and helps to lessen this footprint.
Learn more about the LoneStar on www.InternationalTrucks.com
The International Trucks team
This is an excellent summary of how each of us impacts the environment with the energy we consume daily. Whether it is our televisions, cars or the food we eat, each action and gadget we use leaves a mark which adds greenhouse gases into the atmosphere. The solution is not solely how we use energy, but changing the fuel we use into something that is clean and sustainable. Hydrogen, when utilized in its purest form and produced from renewable sources, is clean with water as the only by-product.
As a representative of The National Hydrogen Association, I have witnessed how organizations, government agencies and scientists are working together to create new the gadgets and cars that takes advantage hydrogen’s versatility as a fuel. Recently, two leading fuel cell manufacturing companies, Ballard Power Systems and Plug Power, released a joint report that confirms fuel cells can improve the environment by reducing greenhouse gas emissions. The report is readily available at Plug Power’s website at http://www.plugpower.com/news/documents/GHG%20FINAL.pdf.
The automotive sector continues to captivate our interest as it seems this is the best way to reduce our carbon footprint. This story emphasizes we must consider our daily activities as well. The versatility of hydrogen as an alternative fuel allows it to be used in a variety of applications such as in specialty transportation to power forklifts and as emergency power stations for cell phone towers. Millennium Cell, a fuel cell manufacturer, is preparing to an emergency power for commercial use: http://gadgetgreeninspector.blogspot.com/2008/01/hydropak.html. Additionally, Motorola is preparing to rollout the first fuel cell powered cell phone: http://www.engadget.com/2008/01/15/angstrom-power-touts-hydrogen-fuel-cells-for-cellphones/
Here's another good way to calculate your carbon footprint, save the planet and offset your carbon emissions...
co2balance can help you ethically minimise your carbon emissions and offset the unavoidable CO2 residue.