Wildfires May Have Greater Impact on Global Warming: The Effect of Carbon

When wildfires sweep across an area, they release a slew of carbon-containing particles, releasing them into the Earth's atmosphere. These fine, carbonaceous particles can degrade air quality. Now, scientists have discovered that the particles emitted by fires are having far more of an effect on climate change than we first thought.

In 2011, a fire took place near Los Alamos National Laboratory. Dubbed the Las Conchas fire, it was the largest of its kind in New Mexico at the time. It burned 245 square miles, sweeping across dried vegetation and spewing smoke. While the after effects were devastating, though, the fire provided the perfect natural experiment for researchers at the laboratory. They monitored the smoke from the smoldering fire for more than 10 days, using an extensive aerosol sampling system.

After sampling the aerosols, it was time to analyze them. The researchers used field-emissions scanning electron microscopy and energy dispersive X-ray spectroscopy in order to examine the samples. It turns out that, surprisingly, spherical carbonaceous particles called tar balls were 10 times more abundant than soot. In addition, the bare soot particles were modified significantly by the organics emitted by the fire.

"We've found that substances resembling tar balls dominate, and even the soot is coated by organics that focus sunlight," said Manvendra Dubey, senior laboratory scientist, in a news release. "Both components can potentially increase climate warming by increased light absorption."

So what does this mean exactly? The different composition from wildfires could drastically increase warming. This could, in turn, have a major impact on current climate models.

"Most climate assessment models treat fire emissions as a mixture of pure soot and organic carbon aerosols that offset the respective warming and cooling effects of one another on climate," said Dubey. "However Las Conchas results show that tar balls exceed soot by a factor of 10 and the soot gets coated by organics in fire emissions, each resulting in more of a warming effect than is currently being assumed."

Wildfires are actually increasing as the climate changes, drying out areas. This means that it's possible that in the future, wildfires could make a huge impact on the rate of warming temperatures. It's therefore more important than ever to factor in the true effect of these fires.

The findings are published in the journal Nature Communications.