Why is everyone talking about their Carbon Footprint?
Scientists believe that the earth's climate is being warmed because increasing amounts of heat-trapping gases are being released into the atmosphere. We are each responsible for some portion of these gases, as they are released in order to produce the electricity we use, when we heat our homes, when we drive our car, in the manufacture of products that we use and their transportation to us, and many other things. To solve the problem, we all need to begin to change the habits that we have that release these gases in such huge quantities. The first step is to become aware of what these are. A Carbon Calculator helps you to understand how much carbon is released from the basic stuff we do.

Is there science behind the calculations of carbon?
Yes there is. The US EPA's carbon calculator (listed first below) is especially good at detailing the scientific assumptions behind their calculations. They have a lot of data to back up these assumptions as well, even if this data is based upon US averages. The problem is that this is actually a very complex problem and each calculator has to simplify the analysis to one extent or another. Read GreenDweller's "Carbon Calculators: What's the Math?" to have a better sense of the pros and cons from the better known calculators. Then try out a few to get a sense of how they work.

• EPA's Personal Emissions Carbon Calculator
• Al Gore's Climate Crisis Calculator
• Acterra's Cool It! Carbon Calculator
• World Resources Institute's SafeClimate Calculator
• Zero Footprint based in Canada

Now that I know how much carbon I produce, then what?
Once we have a good sense of how much carbon dioxide we produce, we need to begin to decrease this by changing some of our daily habits. This web site and many others give you ideas on things that you can do to reduce your carbon footprint. Unfortunately, given the way our world is currently structured, it is nearly impossible to reduce all of the carbon that we produce. Turning down the heat in your home can help reduce emissions from that source—but we still need to heat somewhat. If you shut off your heat but used a wood-burning stove for heat, you would still release loads of carbon dioxide and worse, tons of hazardous particles into the atmosphere (that are actually bad for our health, too). Thus, we look for other things that we can do to "offset" the carbon that we do produce with projects that remove carbon from our lifestyles and the atmosphere in other ways. These are called Carbon Offsets.

How do Carbon Offsets work?
Carbon offsets give us the opportunity to purchase, invest in, donate to or allocate existing dollars to projects and programs that provide a net decrease in carbon emissions. Examples of such projects include the creation of clean energy sources, such as wind farms, solar power generators and solar thermal generators. It can also include programs to increase the sequestration of carbon, such as in the planting of new trees. Technically, an offset projects can involve almost any form of activity that will result in a net reduction of carbon emissions over what would have happened without that project, although the quantification of an environmental educational program or new recycling program will be much harder than that for a wind farm. Some other groups that are offering carbon offset opportunities are listed below:

• Carbonfund.org Carbon Calculator with offset opportunities
• Carbonify.com Carbon dioxide emissions calculator with offsets
• TerraPass Carbon Calculator (a for-profit local company that sells offsets for projects in Minnesota, Wisconsin, Arkansas, etc.)
• ClimateSmart, PG&E's innovative program for California customers to enable them to automatically pay extra (right through their monthly bill) to offset their electric footprint by having PG&E find offset investments on their behalf.
• National Forest Foundation Carbon Capital Fund supporting forestry tree replanting programs

How does the Atherton GreenSTART Fund compare?
While many people are choosing to pay or donate their money to offset their personal footprints, those dollars go to work elsewhere. Atherton is working to promote carbon reduction here at home, where learning and carbon reductions benefit the community. The GreenSTART Fund is a way for residents to support worthy offsetting projects right here in town. The projects that Atherton students are engaging in are all carbon offsetting programs, even if some of the benefits will be hard to quantify (but we are working towards doing this!). Nevertheless, the benefit of supporting the environmental education of our students and raising the awareness of our community is clearly a value to our residents and town. Plus with GreenSTART, residents have a say in selecting which projects should receive additional funding. We encourage our residents to support more than one of these offset programs to reduce their carbon footprints!