Firstly, some very major environmental organizations or foundations don't apparently have any sort of calculator: I can only ask - "What's up with that?" Isn't it part of your explicit or implicit mandate to help change behaviours?
This is a pretty basic tool that every large and serious environmentally-bent organization should have. Outsource its development if necessary, but for goodness sakes, get it done. Some notable laggards in this space include:
- World Watch Institute
- Rocky Mountain Institute
Having said all that, I will review the calculators I came across. From the bottom up:
The Environmental Protection Agency (EPA) calculator
Unfortunately, for a very large agency (in comparison to most of the folks here) charged with protecting the environment, they have a very poor calculator. It misses the diet category entirely, lacks any consideration of "other lifestyle choices", and doesn't compare to a sustainable carbon load. Furthermore, you need your actual energy bills to produce the estimate. Hopefully, the EPA can do better next year, and perhaps one individual there will take it upon him or herself to champion through to completion a top-notch calculator. Grade: Fail. (note to parent - your child has ample resources, please have them bring them to bare on this problem).
Bonneville Environmental Foundation
The choices here are really limited, for your house for instance, you can either pull out your energy bill for your house, or it basically calculates it on a very broad average for a dwelling of that type. Misses diet and "other lifestyle choices" entirely. Grade: Fail (note to parent - this homework needs a serious makeover).
UK Government Calculator
This calculator is sponsored by the British government. It is thorough and extraordinarily deep and detailed in questioning, particularly, about energy use in and about the home, as well as transport use. I have absolutely no doubt that were I a UK resident, I would be able to have a very accurate picture of my home and transport energy use, although this does take a considerable amount of time to complete. Nevetheless, if it were only judged on these issues, it would be a runaway winner.
Unfortunately, it only calculates for UK postal code areas. It also lacks consideration of diet issues, and of other lifestyle factors. For these reasons, it cannot pass. Grade: Fail (note to parent - your student needs to apply themselves equally across the entire assignment).
Home carbon load can be calculated by cost of energy, or actual energy use only, which is a serious deficiency in my view; however, it also allows for a wide variety of location choices, which most calculators don't. However, can only enter 3 flight itineraries; cars (2 only), can choose right from a database that includes mileage; includes mass transit and; asks many detailed questions about other activities; fashion, recreation, recycling, electronics purchases, etc. gives you your total, versus country average, and world target. Personal favorite on the other lifestyle choices, but home energy consumption needs a serious upgrade as does the travel category. Grade: C (note to parent, your students homework shows good potential for a better grade)
Their "one minute calculator" really is simple and easy to use. It has the quickest and simplest interface and, with a bit more detail, could easily be the "one to beat" next year. Although lacking, I could see it becoming a personal and recommended favorite, with some upgrades. However, the home energy use calculator doesn't allow for regional climate variations, and the final number doesn't show sustainable averages or even country averages. Additionally, only one choice can be made for transport, eg driving.
Also, diet questions asks for number of "servings" of this or that; I think that most people have no idea of what a "serving" size is, nor how many they eat in a week. Also entirely lacks questions about other lifestyle choices. Still, as a basic platform, you could do a lot worse than to base it off of this idea. This is easily the most scale able platform, and does a decent job of balancing ease of use, and detail. Grade: C (note to parent - your student has "A" potential).
The Nature Conservancy
US-centric home energy use choices which lets you pick only by state. Moderate choices for home energy use, but on transport can add secondary vehicles. However, flights only give you the option of so many "long flights" and so many "short flights". Ask very basic diet, recycling and waste questions. Gives an average and world average at the end. It has a simple layout, which doesn't take too long to complete. Grade: C (note to parent - your students assignment could have a bit more detail, without losing the ease of use that is valuable here).
World Wildlife Federation (WWF)
Modestly thorough on the house, but lacks questions of location, size, insulation, etc., Obviously designed for UK, but nothing specific indicating that's how house carbon is calculated. Combines travel and transport with very wide ranges given only. Thorough on diet. Questions on "stuff" seem to produce miscalculation, as the purchase of an energy efficient front load washer (to replace my vintage 30 year old top-loader), a cell phone, and a few home improvement tools led to a calculation of over 28% of my personal carbon load.
Also, only calculates tonnes of carbon you are using, and how many "planets" you would use. No comparison to others in your country, or world average. Still, all in all, a decent calculator. Grade: B- (note to parents - a bit more detail on specific locale would be useful, as would a recalculation of the "stuff" category).
Global Footprint Network
This has an interesting interface, which adds to the time required to complete the questionnaire, but also keeps you slightly entertained while doing so. The calculator also offers a choice of a kids questionnaire, or the adult version. It offers a choice of about 15 world cities to choose from for the home energy use calculations. This is also the only calculator that covers water use, as studies have shown there's a very high correlation between water and energy use. It covers almost all categories at least adequately, and took a modest amount of time to complete. The calculator isn't outstanding in every category, but like a hard-working and skilled athlete, it covers every category at least competently. They should, however, show the footprint in relation to international and sustainable averages. Grade B+.
So the winner is, the Global Footprint Network, which will be added as a link on the side-bar shortly.
As a side note to the calculator creators, I can see they struggle generally in two categories. First is the location of the home for energy use calculations - my suggestion here would be to have some sort of drop down menu with a number of world cities to start - more can then be added to as time and circumstances permit. This would allow for more realistic calculations based on the approximate location of the home in question.
Secondly, I would suggest for air travel that the calculation simply be the combination of the two most important factors - the number of flights, and the total hours travelled. This would likely allow a more accurate picture to emerge of the travel carbon picture. All the choices of so many short, medium and long flights, or extraordinarily wide ranges, is misleading, likely inaccurate, and adds an unnecessary element of complexity.
In any case, congratulations to the winner of the First Annual Agitated Ecoist Carbon Calculator Award ... The Global Footprint Network!