Research: wildland fire smoke, including tar balls, contribute to climate change more than previously thought

Manvendra Dubey
Manvendra Dubey

As soon as they were able to repopulate the facility after being evacuated due to the huge Las Conchas Fire in 2011, scientists at the Los Alamos National Laboratory in northern New Mexico set up an extensive aerosol sampling system to monitor the smoke from the smoldering fire for more than 10 days.  The team used field-emission scanning electron microscopy and energy dispersive X ray spectroscopy to analyze the aerosol samples and determined that spherical carbonaceous particles they called “tar balls” were 10 times more abundant than soot. The Los Alamos scientists were the first to discover tar balls and coated soot.

Senior laboratory scientist Manvedra Dubey noted that, “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. 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 assumed.” He said this should have a huge impact on how the aerosols are treated in computer models.

These photos of soot particles from the Las Conchas Fire are from a paper written by Mr. Debey and the three other scientists from Los Alamos National Laboratory listed below.

Bare soot particle
Bare soot particle. Los Alamos National Laboratory image.
Embedded soot particle
Embedded soot particle. Los Alamos National Laboratory image.

Mr. Dubey, along with postdoctoral fellow Allison Aiken and post-bachelor’s student Kyle Gorkowski, coordinated with Michigan Tech professor Claudio Mazzoleni (a former Los Alamos Director’s fellow) and graduate student Swarup China to perform the study.

This week on Twitter Mr. Dubey solicited and then answered questions about his fire smoke research:

Lab Chat Q&A Summary

1. Q: Wildfires contribute to global warming, but also help to make forests healthier naturally. So do we fight them or let them burn?

A: We have been fighting fires so forests are dense. Warming will exacerbate and we may not be able to fight future intense fires.

2. Q: What equipment was used to analyze/ discover tar balls? Are there other institutions studying these effects?

A: Field Emission Electron Microscopy for shape, and Energy Dispersive X-ray spectroscopy for elements.

3. Q: Why haven’t tar balls been recognized before as a problem?

A: Experimental techniques were limited. Our research is the most exhaustive & detailed. About 5,000 particles were analyzed.

4. Q: What are the effects of a tar ball release like Las Conchas compared to fossil fuel greenhouse emissions? Are they equivalent?

A: GHG emissions build over time, causing much greater forcing of climate. Wildfire amplify this by emitting tar balls and soot.

5. Q: Because of your research, does this mean current climate modeling is wrong?

A: No. Climate models provide the right physical framework. Our results provides more realistic input data on fires.

6. Q: Is climate modeling going to be more pessimistic now with this new information?

A: Probably. In current models the net climate effect of fires is small. We show that the feedback from fires will be positive.

7. Q: Is there a specific element of forest fires that creates tar balls?

A: They are basically made of carbon, oxygen, and hydrogen. Created by burning lignin & cellulose in wood.

8. Q: Are there any laboratories doing similar research and did they get similar results?

A: Yes-DOE/Science labs with much more funding do similar work. We were agile to first discover the tar balls & coated soot.

9. Q: How long did this research take to conduct?

A: The experiments took 2 weeks, the capability to do this was developed over 5 yrs, the analysis & writing took about 2 yrs.

10. Q: Do tar balls say in the atmosphere forever?

A: No, typically they last for a week before they are rained or deposited out. In a week they can be lofted and carried around the globe.

11. Q: Have tar and organics ever been considered in modeling at all?

A: No IPCC models treat tar balls, they do treat organics. There are some recent attempts to include them, but this is ongoing research.

12. Q: Since current climate models struggle with regional resolution, how can tarball effects be taken into account?

A: We specify the location of fires scaled to the grid size. The models then transport them & treat their climate impact.

13. Q: Are you currently examining the large fire in northern Quebec for tarball emission/effects?

A: No. We need more funding to do this research and hope to do it in the future.

14. Q: How exactly do “tar balls” increase climate warming and how significant is the effect?

A: They are brown spherical particles that absorb sunlight in the UV, warming the atmosphere. We are modeling to quantify it.

15. Q: Does anything counteract tar balls and soot?

A: Organics in smoke are white and offset the positive feedback, but fundamentally you have to reduce your carbon footprint.

16. Q: What is the most important thing an individual person do about Global Warming in your opinion?

A: Conserve energy and reduce their carbon emissions.

17. Q: Are tar balls a problem in wildfires worldwide or is it a regional issue?

A: It is a global issue. Tar balls are made in all types of wood combustion from wildfires in the U.S. to wood-burning in India.

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Author: Bill Gabbert

After working full time in wildland fire for 33 years, he continues to learn, and strives to be a Student of Fire.

5 thoughts on “Research: wildland fire smoke, including tar balls, contribute to climate change more than previously thought”

  1. I won’t dispute the fact that smoke amy or may not play a role in climate change. However, if it does play a larger role, Climate change was set in motion way before we ever set foot on a fire. If you look at it realistically, prior to our intervention fires burned freely across the land scape. So I submit that there is less smoke now than historically since we put the majority of fires out.

    1. While I’m not an expert in paleoclimatology, it’s pretty well established that there were massive wildfires in the distant past involving a “significant fraction of global biomass” that are considered contributing factors in climate change. The source below references specific studies with more detailed info.
      Source: Encyclopedia of Paleoclimatology and Ancient Environments, V. Gornitz via google books

      1. So, yeah, you’re right about more in the past. I suspect there are ice cores that tell the story as to comparing current total particulate matter in the air with historic patterns.

  2. I would have to believe the that fire size, intensity, nature of combustion, fuels and fuel loading, atmospheric conditions, etc. would all contribute to the nature of the smoke that any single fire produces. The Las Conchas fire burned under specific conditions and the collection site sounds like it was only several miles from the fire location. Were these very specific conditions/assumptions considered before making the conclusion that the results from this single case event applied to all forest fires in how they impact the global climate system?


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