What's the Best Way to Barbecue?

Memorial Day is upon us, and the backyard grilling season is moving into full speed, giving rise once again to that hotly debated question: Which is best, charcoal or gas?

Setting taste aside for the moment, there is some evidence these days that if you think charcoal is less damaging to the environment you could be dead wrong.

A researcher in England has concluded that the carbon footprint for charcoal is about three times as big as the footprint from burning propane, the most common alternative to charcoal.

That's consistent with a study a few years ago from Oak Ridge National Laboratory, which looked at the impact from all those grills fired up on the most popular grilling day of the year, Independence Day.

Charcoal vs. Gas Debate Heats Up

That study concluded that enough energy would be burned on that single day to meet the residential demand of a city the size of Flagstaff, Ariz., with 21,000 households.

Those grills would emit nearly 225,000 metric tons of carbon dioxide, a greenhouse gas, the study concluded, especially since charcoal is the preferred fuel for nearly half of America's backyard chefs.

It will also burn the energy equivalent of 2,300 acres of forest.

The study argued that if the 34 million gas grills that were expected to be fired up for that day were instead fueled by charcoal, an additional 89,000 tons of carbon dioxide would be emitted. And if the charcoal grills could be switched to propane, carbon dioxide emissions could be reduced y 26 percent, or about 59,000 tons, the study found.

Case closed, right? Well, it's not all that simple.

In a study published in the current issue of Environmental Impact Assessment Review, environmental researcher Eric Johnson looked at all phases of the production, transportation and consumption of both propane and charcoal in the United Kingdom.

His findings were based partly on the fact that the charcoal consumed in England comes mainly from developing countries, especially Africa.

Much of the charcoal from those countries is produced in a pretty simple way -- trees are set on fire, buried under dirt, and left there until the wood has been reduced to dry carbon, the principal component of the stuff used in backyard grills.

Industry Group: Charcoal Sold in U.S. Is Cleaner Than Charcoal Elsewhere

But according to the Hearth, Patio & Barbeque Assn., an industry trade group, most of the charcoal sold in the United States is produced in this country using technology that is much cleaner than the methods used in developing countries.

Of course, the carbon dioxide released by charcoal is already in the environment because it had been temporarily stored in wood, and the greenhouse gases from propane had been sequestered deep in the earth and their release adds to the overall amount.

So the impact is not precisely clear, although studies have shown that charcoal is a far less efficient fuel than propane, so it would take significantly more charcoal to burn that dog than propane.

Meanwhile, other researchers have concluded that charcoal could actually be a lifesaver if it could be substituted for wood in many developing countries.

Study: Millions Could Be Saved in Africa by Switching From Wood to Kerosene and Propane

One major study by the University of California, Berkeley, and the Harvard School of Public Health found in 2005 that pollution from wood fires kills more than 1.6 million people, primarily women and children, in third world countries from respiratory diseases caused by the pollution from wood fires.

As many as 1.3 to 3.7 million persons could be saved from premature death if Africa could rapidly switch from wood to kerosene and propane, that study concluded, although that change was not deemed likely. Many lives could be saved, however, if more Africans could switch from wood to charcoal, the researchers found, but even that has its downside.

Charcoal burns cleaner than wood, the researchers said, but the way charcoal is produced in Africa is so inefficient that it has become a huge source of global pollution.

"Most charcoal is produced in Africa by one or two guys going out in the woods, almost always without a permit and on somebody else's land, cutting down a tree or two, chopping it up, lighting it, covering it with dirt, and then hovering around it for two to four days while it becomes charcoal," University of California Berkeley energy professor Daniel Kammen said in releasing the study.

Is Grilling Really the Healthy Alternative?

Randomly chopping down trees is also pretty hard on the forest, which today is still one of the first lines of defense against global climate change because of the ability of trees to sequester carbon, at least for a few decades.

The biggest concern among many backyard chefs, however, has little to do with British thermal units contained in a typical briquette, or pollution caused by burning charcoal, or even saving lives in Africa by switching to charcoal from wood.

Is grilling really the healthy way to go?

Surf the net for a while and you'll find all sorts of claims ranging from the family barbecue pit can give you cancer to the amount of pollution caused by backyard grilling is so slight compared to other sources that it isn't worth worrying about. Maybe so, on both counts.

Charcoal Appears to Leave Larger Carbon Footprint Than Propane

There's some evidence that grilling can expose you to carcinogens, regardless of which fuel you use. The problem, according to cancer researchers, is in the temperature, not the fuel.

If you like your steak well done, burning it around the edges produces chemicals called heterocyclic amines, according to the National Institutes of Health, which are known to cause cancer in animals and are suspected of causing cancer in humans.

But those chemicals are produced by excessive heat, whether it's a grill or a frying pan on the kitchen stove. There is some concern also that fat dripping from the meat onto the heat-source causes smoke that can add additional chemicals to the meat, but that's a matter that is still debated.

Although there's no absolute answers to these questions, there does seem to be a trend in the various studies. It does appear that charcoal leaves a larger carbon footprint than propane, burning your red meat is not a good idea, and grilling veggies may not be as much fun, but it's probably healthier.

Bon appetite.