Where There’s Smoke, There’s Climate Change: New Connections Between Climate Change and Wood Burning

Burning wood produces soot and methane, the second- and third-leading causes of global warming, respectively. Soot, also known as black carbon, kills approximately 1.5 million people per year worldwide, and methane increases ozone, which negatively impacts global health.

Not only are black carbon and methane themselves pollutants, but increasing levels of these combustion products lead to temperature increases that in turn worsen the health effects of air pollution. A recent study at Stanford University notes, “Controlling soot and methane may be the only methods of preventing loss of the Arctic sea ice and a tipping point to more rapid global warming.”

The impact of black carbon on climate change, especially as it impacts California, was the focus of the California Air Resources Board Meeting on May 24, 2012. Scientists from the EPA, Stanford University, UC Berkeley, UC San Diego, and the Pacific Northwest National Laboratory described how soot and brown carbon (a combination of soot, methane, and other fine organic particles) are affecting our climate at the regional and global levels in ways that undermine the very foundations of our climate systems.

The presenters noted that black and brown carbon are principally regional pollutants formed by incomplete combustion of fossil fuels, biofuels, and biomass such as wood. The resulting fine particles go directly into the atmosphere, remaining aloft for days or weeks. According to the EPA, “Controlling direct fine particle emissions from sources can be a highly effective air quality management strategy, with major public health benefits. Targeted reductions in black carbon emissions can provide significant near-term climate benefits.”

Reducing wood burning reduces the production of black and brown carbon as well as methane and may help slow climate change. In addition, reducing wood smoke will improve air quality, improve public health, and relieve some of the burden on the climatic systems that sustain life on earth.

Children’s Exposure to Wood Smoke: Small People, Big Problems

There are several new studies that show how pollution from biomass combustion, such as wood burning, has negative impacts on children’s heath. Some of these effects occur during pregnancy, creating lifelong damage to the developing fetus. From rural cook stoves in Africa to the mix of urban pollution in American cities, mothers and children are increasingly exposed to toxins and carcinogens from wood smoke, and their health is being compromised at unprecedented levels.

According to researchers at the University of California at Riverside and at Pitzer College in Claremont, California, children exposed to open-fire cooking in developing countries experience difficulty with memory, problem-solving, and social skills. The study concludes, “Exposure to wood-burning stoves may be more damaging than people realize. It could have cognitive and behavioral effects.”

Recent studies have also shown that prenatal exposure to air pollution can slow lung development in children and cause respiratory ailments, such as allergies and asthma.

These new studies highlight the fact that wood smoke is not only dangerous for those who are already at risk, such as those who suffer from asthma or cardiovascular illness. Wood smoke and other pollutants are also dangerous for developing fetuses and children in ways that are much more profound and long lasting than thought previously.

These studies join the growing body of evidence that wood smoke is a major public health threat that needs to be addressed in order to protect our children’s health and well-being.

Warm-weather Wood Burning: Pollution in Our Own Backyards

The weather is heating up, and homeowners are not burning as much wood to stay warm. Now we can all take a deep breath without fear of inhaling wood smoke, right?

Not quite. Unfortunately, the increasing popularity of backyard fire pits and “chimineas” is creating a new reason to worry if you like to breathe clean air. Burning wood in outdoor fire pits and chimineas is just as bad for air quality as burning wood in a fireplace or wood stove. The same pollutants, including particulate matter and dioxin, are produced. Worse, burning wood in the backyard eliminates the “smokestack” that normally releases these pollutants away from ground level; this results in more direct inhalation of the toxins.

Sitting around a camp fire, backyard fire pit, or chiminea thus results in much more immediate, concentrated exposure to harmful particles and since there is not as much opportunity for dispersion. The Canadian Lung Association notes, “Wood smoke from chimineas may stay closer to the ground since they have low chimney stacks and can pose a problem for neighbors.” The upshot is that those in the immediate vicinity of the fire inhale large quantities of wood smoke pollution, and their neighbors get a big dose as well. Children are especially vulnerable, as their respiratory systems are still developing and they breathe more air (and air pollution) per pound of body weight than adults.

While the romance of an outdoor fire is just as alluring as that of a blazing log in the hearth of your living room, please consider the damaging effects of these fires on your health and that of your children and neighbors. We all deserve to have healthy air and to enjoy our backyards without breathing in the pollution from an outdoor fire.

Greenhouse Gases from Wood are a Burning Issue

The International Panel on Climate Change (IPCC) has proven that particles created by burning wood and other biomass—so called “black carbon”—are a major contributor to global warming.

Just like coal, oil, and natural gas, the greenhouse gases (GHGs) sequestered in wood are released to the atmosphere when we burn it for fuel and heat. But while there is agreement that burning wood releases GHGs and creates black carbon, some argue that wood burning is “carbon neutral” because it releases about the same amount of GHGs that is released when a tree decays naturally.

Technically this is true; however, it’s important to consider the factor of time as it relates to burning vs. decaying. It takes over 15 years for a typical tree used for wood burning to mature before it is harvested.  During that time, the tree is storing CO2 that it collects from the atmosphere. Given the opportunity, that tree could live for another hundred years or more, continuing to collect and store GHGs. After it dies naturally, it will take many more years for it to decay and gradually release the GHGs it collected over its lifespan. However, if the tree is burned in a fireplace or woodstove, all those GHGs are released in just a few hours and in higher concentrations.

This difference in timescale is critical. The IPCC has developed a set of projections for the dire effects of climate change. Their report presents a range of scenarios based on how quickly we can reduce our GHG production and how fast we can lower the concentrations of GHGs already in our atmosphere. Many scientists believe that reducing or eliminating wood and other biomass burning to be one of the easiest and most effective ways for us to curb global warming.

The need to reduce deforestation in places like the Amazon and Africa, and in fact the need to plant MORE trees to sequester CO2 and other GHGs, has long been known. But we also need to make the connection to wood burning in our homes here in North America. If we immediately reduce our reliance on wood for heat and break our habit of burning wood for ambiance, we can make a significant contribution to reducing GHGs and black carbon and help avoid some of the most extreme effects of climate change that are predicted by the IPCC.