Calculating That CO2 Footprint

Austin has a new addition to the carbon-offset business, the oft-criticized $55 million-a-year industry that lets you mitigate your carbon-dioxide emissions through clean-energy and carbon-sequestration investments. Chief among criticisms is the system's lack of accountability: It can be hard to tell what exactly you're buying or whether the beneficial activity might have happened without your investment anyway. So critics often are calling for more transparency, ideally through "local" investment options. And Austin nonprofit TreeFolks have answered that call.

The 18-year-old urban forestry organization already has a reputation for diligence: Every locally grown, native tree it plants has a contractually obligated caretaker, and volunteers revisit each tree to track survival. So it's fitting that in developing a carbon-offset system, TreeFolks "erred way, way, way on the side of accountability," as Executive Director Scott Harris puts it. TreeFolks' carbon calculator determines how many trees you need to buy to offset your emissions, based on the most conservative carbon-output estimates his research team could find, Harris says. Plus, after purchasing your trees, you get a certificate detailing when and where they were planted. As Harris likes to point out, he can "take you by the hand and point to your tree."

Such diligence has its drawbacks. Right now, TreeFolks can help you green up your wedding or office party, but it won't soon be offsetting any South by Southwest-sized footprints. Local fests like SXSW and Austin City Limits have used the offset program belonging to Green Mountain Energy, a national company headquartered in Austin since 2000. According to Gillan Taddune, Green Mountain's chief environmental officer, such festivals emit between 600 and 1,000 metric tons of CO2. By contrast, a large wedding that worked with TreeFolks this summer had only a 13-ton impact, Harris says.

Aside from its size, TreeFolks' other drawback is, well, trees, which arguably don't make the best carbon sinks, depending on species, lifespan, climate, and other variables. TreeFolks' calculator does include a high tree mortality rate to ensure that if some of your trees die, enough will remain to offset your emissions. Harris also points out that urban trees are particularly effective at absorbing CO2 (because of proximity to the source), and they help shade homes and mitigate the urban-heat-island effect, decreasing the need for emissions-causing air conditioning. These factors make TreeFolks' home-turf advantage particularly beneficial to Austinites. Through Green Mountain, SXSW and ACL have been able to offset their emissions in Texas – with wind-farm investments in Brazos and tree-plantings in Red River County – but TreeFolks stick with native trees, all planted right here in Austin's urban environs.

According to city of Austin Sustainability Officer Fred Blood, tree-planting will likely be a component of the city's carbon-offset program, which has been in development since the February announcement of the Austin Climate Protection Plan (see "Cool City"). Blood is quick to point out the many drawbacks of carbon-offset systems, which rely so heavily on varying estimates to determine, for instance, the impact of one person's ride on an airplane that would have flown regardless. But these calculations continue to improve, he says, so you don't want to "let the perfect interfere with the possible." The city's program will include both international and local investment options, which is where trees would come in. They may not be ideal, he says, but they're better than nothing – and with the city's program several months out, "nothing" is the only truly local alternative to TreeFolks.