In my line of work one sometimes hears strange things. These include allegations that leaf blowers or pet manure should be high priority targets for reducing climate emissions. I’m in a myth-busting mood today, so I am happy to report that leaf blowers don’t really rate.

In the US, the emissions from all leaf blowers, both residential and commercial, for all of 2008 will be roughly equivalent to the emissions from driving that occurred between the arrival of the new year and 11:00 a.m. on January 1.

Add to that the entire year’s worth of snowblowers, and you can equal the driving emissions up until 1:30 p.m. on the first.

Add in all lawn mowers, both residential and commerical, including the big riding and tractor-type units. Add in rototillers and other turf maintenance equipment. Add chainsaws, chippers, stump grinders, and shredders. Now add trimmers, edgers, brush cutters, and any other garden tool you can think of. The combined emissions from all of that racket-making equipment, for the entire year, is roughly equal to the driving that occurred before afternoon rush hour on January 6.

Of course, that’s not really the whole story.

  • Here’s a different way to think about leaf blowers: they emit more than 2.6 million tons of carbon-dioxide each year in the US. And each year they burn enough fuel to fill 6.4 million oil barrels. (More than 90 percent of the fuel use and emissions are from commercial leaf blowers.) Now, that sounds like a lot because it is a lot. It’s just that it’s nowhere near the impact of driving—not even a single day’s worth of driving.

    So, from the perspective of climate protection, it makes more sense to go after the big fish—cars and trucks—where even a tiny improvement can translate into a huge gain.

    On the other hand, from the perspective of protecting local air quality, it might makes sense to worry about yard equipment. They have small but dirty two-stroke engines that can be responsible for a surprising share of health-harming air pollutants. (But these pollutants are mostly not the heat-trapping gases that cause climate change, a distinction that is frequently overlooked.)

    The most important perspective, however, is the perspective of not-annoying-me-while-I’m-enjoying-a-cold-drink-on-the-patio. From this vantage point it would be wise to replace gas-powered yard tools with electric or muscle-powered versions. And one good place to start would be my neighbor’s lawn mower.

    Figures in this post are calculated from the US Department of Transportation, “Transportation Energy Data Book,” table 2.10, here; and the Federal Highway Administration’s “Highway Statstics Series,” Table MF-21, here. I used 2005 data, the most recent available for comparison; and for rhetorical purposes I assumed that driving emissions are equally distributed across each hour of the year, which they aren’t.