The organization I work for had its first fundraising event on Sunday. I decided to use it as an opportunity to figure out how to make the event "carbon neutral." The biggest benefit to the project was in learning how to think through what it means to be "carbon neutral" in practice. That meant understanding the CO2 implications of our actions - not just viewing an event in isolation, but really thinking about what it means to the planet, and then thinking about what choices we can make to counteract the impacts.

Basically, there were three steps in the process:

First, we had to figure out how much CO2 the event would generate.

We were hoping for about 200 people, and I estimated that they would arrive in 150 cars, and that each car would travel an average of 40 miles round trip,and the average car would get 20 mpg. We would have the facility for 4 hours, and a meal would be served.

I used several calculators to help me estimate the impact.

 Travel was easy. Assuming 150 cars traveling 40 miles each, getting 25 mpg, that's 6,000 miles, 240 gallons of gas, which translates into 4,800 pounds of CO2 (20 pounds per gallon of gas).

The facility's CO2 emissions were more difficult. The best calculator I found was through a site for The Climate Trust in Oregon. They have a companion website called Carbon Counter that has calculators and allows you to purchase offsets. Through their site, I calculated that the facility use would generate about 3,000 additional pounds.

So, that put us at roughly 4 tons (2,000 pounds in a ton).

We could have purchased offsets to help generate clean energy in some other part of the country, but that just didn't seem quite right. So instead, we decided to figure out how many trees we would have to plant locally to absorb the carbon produced by the event.

One tree, over it's 90-120 year lifespan will absorb a ton of carbon in its roots, trunk and branches. So, if we planted four trees, over the next 100 or so years, they would absorb an amount of CO2 equivalent to the amount generated by the event.

That seemed kind of lame.

Planting 400 trees would absorb about 4 tons of carbon in one year (on average). And they would do that year in and year out for about 100 years. That is great, but planting 400 trees is a lot of work!

I checked on some tree "offset" websites and found that they use the figure of 3 trees per ton of carbon for offsetting your CO2. Well, if we planted 12 trees, that would still take 30 years to absorb the CO2. That seemed slightly less lame than 100 years, but still, 30 years is a full generation.

Instead, we decided to take a middle position and go with 10 trees per ton - a 10 year return, plus the trees will continue absorbing carbon for about 90 years after the initial 10.

Just think, if everyone planted trees to offset their carbon! Not a bad thing.

 

 The third step in the process was planting the trees. And we did. 42 oak trees were planted on October 1st as part of a project to reforest the once abundant woodlands of this area. And we know those trees will be doing something else - they will be absorbing CO2 as the grow! A two-fer!