Eating local makes sense for a lot of reasons, both environmental and social. Certainly my main motivations are to reduce the carbon load in the atmosphere, and to foster the creation of a civilization that can function on current solar income.

Preindustrial levels of the primary greenhouse gas, carbon dioxide were about 280 parts per million (ppm) and are now soaring above 380 ppm. This increase is almost totally caused by the combustion of fossil fuels, such as oil, natural gas and coal. For the first time in human history we are mining ancient sunlight, becoming totally dominant on the planet, causing a mass extinction crisis, and endangering our own survival. For folks like me in the industrialized countries the challenge is to reduce the amount of fossil fuels used, both directly and indirectly, by ca. 90% over the next few decades. Eventually, we will have to do practically without them completely.

Most people have no idea what it means to cut back by that much--to 1/10th their current usage of fossil fuels. So I thought I'd check out some ways people can get a handle on what habits they have and infrastructure they depend upon that is fuel intensive. I did a google search on the terms "carbon calculator" and found these sites:

(Before using these it could be handy to have your utilities bill, your automobile service records, and your calendar handy.)

http://www.climatecrisis.net/takeaction/carboncalculator/#

This one is related to the Al Gore film and a company that invests in renewable energy. It estimates emissions from personal travel and home. Then it allows you to pay for "offsets" based on your sins. This is pretty controversial. We need to invest in renewable energy AND reduce emissions. Keeping emissions constant and building renewable energy infrastructure will not solve the problem AT ALL. But if this helps people cut back, that is good. This calculator notes that the US average personal emissions is 15,000 lbs per year. So that should get down to 1500. How close am I?

My results for this calculator were: 2800 lbs per year

http://www.safeclimate.net/calculator/

This is the World Resource Institutes calculator and it pretty much has similar variables as the one described above: home and transportation. But the inputs are not identical so it goes about some of its calculations a bit differently. This had a nice graphic that showed that 68% of my emissions are from transportation and 32% from household. A very interesting result since I don't fly anymore and my estimated automobile miles per year are 3600, both very low compared the US average. Even so, transport is where I still have the most emissions!

My results for this calculator were: 4079 lbs per year

http://www.carbonneutral.com/uscalculator/index.asp

This is from a United Kingdom reforestation company. You put in your flights and it puts it in terms of how many trees you should fund the planting of. Nifty, but again, this won't do the trick. We can plant trees till we reforest Europe and if we don't cut back on emissions it won't do ANY GOOD! Must plant trees while cutting back. It also asked about car travel, size of engine, and home electricity and fuel usage. It didn't have a choice for natural gas in therms, but in kwh, so I had to use this calculator to convert it: http://www.projects.ex.ac.uk/trol/scol/ccenrgy.htm. A nice feature of the output was that it broke down the C02 emissions into the various categories. And guess what! My car emissions are less than my household. This may be explained by the fact that it didn't ask me how many members are in my household, just total household and my total travel. But both household and travel emissions are often shared. So it may be difficult to directly compare this calculator to the previous. The results suggested my household could fund the planting of 8 trees in Britain to offset our carbon footprint. Poppy cock!

My results for this calculator were: 9385 lbs per year (the difference being that the others asked me how many people were in my home, this one didn't, so divided by 4 and it is 2346 lbs per year, about similar).

http://www.resurgence.org/carboncalculator/

This is another UK calculator. It is more detailed than the others, but didn't have a US input data option so I didn't work it out. For example, electric bills are given in kilowatt hours (kwh) and the carbon intensity of those kilowatt hours depends upon what grid you are connected to. California has less coal and more natural gas than the midwest. France has more nuclear. I'd like one like this for around here.

http://carbonfund.org/site/pages/calculator/

This one looks easy to fill out too, but same inputs as usual. Something is missing from all of these. Do you know what it is?

I finally came across a page that lists available calculators:

http://www.earthfuture.com/climate/calculators/

One of its links is:

http://www.carboncounter.org/

This site has a figure that is much higher than the others suggest. It says "The average American produces about 40,000 pounds of CO2 emissions per year." Aha! Finally a site that is getting at a true figure. Why is this so much higher than the 15,000 pounds per American referenced on the other site? Perhaps it has to do with "embedded" energy use and systemic use beyond the household and personal transportation? We may ride a bike to the grocery store, but how did our food get there? Probably not on horse back.

My results for this calculator were: 33,380 lbs per year using the "estimate" version and 9300 lbs per year using the "exact" feature (didn't ask how many people per household so results on par with carbonneutral.com). Yowza! That estimator was way off and if I flew a couple of times I could have easily been pegged as average, i.e., 40,000 lbs per year.

I think to get a better idea of our true impact we need to look at a broader measure than these personal carbon calculators. We should try instead the ecological footprint calculators. These place individuals in the context of an economic system and the flows of materials and energy of our society are part of our own responsibility. If our government decides to build a super highway system instead of light rail for travel and we pay for that in our taxes then it is part of our personal footprint.

Personal change can only go so far. Unless we change how our economy is structured and how we house and transport ourselves and the goods and services we rely on, our fossil fuel use will be very high. While outstanding to do, no tree planting or renewable energy farms will compensate for these emissions.

http://www.myfootprint.org/

This is a well known footprint calculator based on the original Ecological Footprint. The questions on this one are much more sophistocated than in the carbon calculators, asking questions about food choices and distance food travels! The average US footprint is 24 acres and given the population of the planet there's enough space for 4.5 acres per person.

My footprint using this tool was: 8 acres

http://www.ecologicalfootprint.org

A new, very simple calculator was developed by the folks who came up with another version of the Ecological Footprint. It is not possible to directly compare the outputs of these two versions of the Ecological Footprint. The average global footprint is 21 hectares. In the US this is much higher and about 95% of the US footprint is due to energy consumption! My footprint is surprisingly low using this calculator and by no means was I totally ecogroovy on this site. I do eat meat (almost always local though) and our home is of average size and stand alone, not a small apartment. But I don't fly and ride a bike for my daily transportation. I think that weighed very heavily in this tool.

My footprint using this tool was: 10 hectares or ca. 25 acres