Read more from Slate’s Summer Vacation special issue.
Barbecue season is upon us, and I’m wondering about the greenest method for cooking up my legendary T-bones and sweet sausages. Should I stick with charcoal, which I’ve used for years, or should I finally make the switch to gas?
If you’re concerned solely with the carbon dioxide that wafts off your grill, then gas is the easy choice. But if you step back and consider the whole production cycle, then certain types of charcoal may well be the greener cooking fuel. The real trick, as is so often the case, is to select a product that’s been created conscientiously—a tough assignment, given how little information manufacturers typically provide.
The indisputable part of the charcoal-vs.-gas conundrum is that the briquettes emit far more carbon dioxide per unit when they’re burned. According to Oak Ridge National Laboratory, obtaining a British thermal unit’s worth of energy from charcoal produces three times the carbon emissions as a BTU from natural gas. When taking into account the amount of fuel needed to run a barbecue for an hour, a gas grill puts out 5.6 pounds of carbon, while a grill using briquettes pumps 11 pounds of the stuff into the air.
But charcoal’s defenders point out that because the substance is made from trees, it can actually be carbon neutral in the end. They contend that the harvested trees, if taken from well-managed timberlands, are presumably replanted. So, while the felled trees are emitting carbon on barbecues nationwide, the new trees are sucking that carbon right back up. Gas, on the other hand, can’t be replenished—or at least not for the millions of years it takes for organic matter to break down into fossil fuels.
On top of that, briquettes are made primarily from wood waste, such as sawdust, which would simply be thrown away if it weren’t turned into cooking fuel. So, it’s not as if we’re cutting down forests simply to make briquettes—they are, instead, a byproduct of the paper-manufacturing process. (Lump charcoal, made from whole pieces of wood, is more problematic from an environmental standpoint, since it may require that trees be chopped down expressly for the purpose of making barbecue fuel.)
The major problem with most briquettes, however, is their nonwood additives, such as coal, borax, and sodium nitrate. These are added to aid ignition and ensure slow burns yet end up causing appreciable emissions of smog-forming particulate matter. Another downside to briquettes is the energy that must be expended to bake them into shape. Some charcoal manufacturers claim to capture the excess heat from this kilning process and use it to generate electricity for their factories. But it’s unclear how much energy savings this provides or how much fossil fuel they use to create a bag of briquettes.
There are several briquettes that claim to be eco-friendly, most notably those from Wicked Good Charcoal, which are certified as coming from sustainable timber operations by the Forest Stewardship Council. Wicked Good’s briquettes are also additive-free. For a truly green grilling session, though, the company recommends that you eschew lighter fluid, which contains volatile organic compounds, in favor of a chimney starter.
No matter how it’s made, charcoal still presents a disposal issue once the grilling is done. While the ash from additive-free lump charcoal can be used occasionally by skilled gardeners, it’s usually best to toss out charcoal remnants (especially those from mainstream, chemical-rich brands). Gas provides no such disposal quandary—it’s either piped in from a home hookup or siphoned off from metal canisters that can be refilled again and again.
The Lantern personally prefers environmentally sound briquettes like those from Wicked Good but more for the taste than to protect the Earth. If you don’t like that charred flavor, go ahead and use gas, but please do so responsibly—for example, don’t leave the grill on for unnecessarily long stretches of time. Perhaps gas does a bit more long-term harm to the environment, in terms of increasing the amount of carbon in the atmosphere, but the effect is minuscule: Barbecue emissions account for 0.0003 percent of our nation’s annual carbon footprint.
The situation is quite different in Africa, however, where a significant amount of cooking is still done over wood fires. According to a 2005 study by researchers from the University of California-Berkeley and Harvard, the pollution from those fires causes 1.6 million premature deaths each year, primarily from respiratory diseases. If those fires ran off sustainably created charcoal or gas instead, millions of lives would be saved.
Is there an environmental quandary that’s been keeping you up at night? Send it to firstname.lastname@example.org, and check this space every Tuesday.