Soot is heating up the planet, experts warn

U. LEEDS (UK) — Soot’s role in global warming may be underestimated, but a major effort in reduction could potentially gain us a few decades of relief.

The direct warming effect of black carbon, the term used by scientists to describe soot, could be about twice the previous estimates, according to a study published in the Journal of Geophysical Research Atmospheres.

Black carbon is believed to have a warming effect of about 1.1 Watts per square meter (W/m2), approximately two thirds the warming effect of carbon dioxide—the largest man-made contributor to global warming—and greater than that of methane.

The figures indicate there may be a greater potential to curb warming by reducing soot emissions than previously thought.

Professor Piers Forster from the School of Earth and Environment at the University of Leeds, who co-led the study, says: “There are exciting opportunities to cool climate by cutting soot emissions, but it is not straightforward.

“Reducing emissions from diesel engines and domestic wood and coal fires is a no-brainer, as there are tandem health and climate benefits.

“If we did everything we could to reduce these emissions, we could buy ourselves up to half a degree less warming—or a couple of decades of respite,” Forster says.

David Fahey from the US National Oceanic and Atmospheric Administration (NOAA), says: “This study confirms and goes beyond other research that suggested black carbon has a strong warming effect on climate, just ahead of methane.” Previous studies had also indicated underestimates of some regions’ soot emissions.

Sources of soot

Huge quantities of man-made soot enter the atmosphere every year, with about 7.5 million tons emitted in 2000 alone. These emissions come from a variety of sources.

The largest global cause is the burning of forest and savannah grasslands, but diesel engines account for about 70 percent of emissions from Europe, North America, and Latin America.

Residential fires contribute 60 to 80 percent of Asian and African emissions, and coal fires are also a significant source of soot in China, some Eastern European countries, and the former USSR.

The small, dark particles that make up black carbon directly heat the atmosphere by absorbing incoming and scattered heat from the sun. They can promote the formation of clouds that can have either cooling or warming effects. Black carbon can also fall on the surface of snow and ice, promoting warming and increasing melting by reducing light reflection.

“Mitigation is a complex issue because soot is typically emitted with other particles and gases that probably cool the climate,” Forster says. “For instance, organic matter in the atmosphere produced by open vegetation burning likely has a cooling effect. Therefore the net effect of eliminating that source might not give us the desired cooling.”

Immediate effects

There are some targets for reduction that scientists believe will have a clear benefit.

“One great candidate is soot from diesel engines. It may also be possible to look at wood and coal burning in some kinds of industry and in small household burners. In these cases, soot makes up a large fraction of their emissions, so removing these sources would likely cool the climate,” Forster says.

Reducing black carbon emissions has a major advantage: its effect would be seen almost immediately because black carbon’s influence is a continuous short-term process. While carbon dioxide remains in the atmosphere for relatively long periods, existing soot emissions are washed out of the atmosphere in a few weeks.

However, black carbon reduction could only be part of a solution. Forster says: “Soot mitigation is an immediate effect but helps for a short time only. We will always need to mitigate CO2 to achieve a long-term cooling.”

The report finds black carbon is a significant cause of the rapid warming in the Northern Hemisphere at mid to high latitudes, including the northern United States, Canada, northern Europe, and northern Asia. Its effect can also be felt further south, causing changes in rainfall patterns from the Asian Monsoon. Curbing black carbon emissions could significantly reduce regional climate change, while also having a positive impact on human health.

The International Global Atmospheric Chemistry Project (IGAC) commissioned the study.

Source: University of Leeds

chat15 Comments


  1. Dave Gleason

    Okay – so you are nuts, why do you think that the rest of us are nuts? Everyone knows that the earth has ALWAYS gone through normal cycles of climate change and that it has NOTHING to do with man. You are just trying to profit off of fear, taxation, and manipulation. WAKE UP!!! We don’t buy your lies.

  2. Ben Nevis

    I call BS…everyone should know that soot falls out of the air within a mile of the emitter. Soot is not a gas, it is heavier than air. Don’t believe the ‘man made climate change’ rhetoric…it is a scheme to keep us poor and in the control of the political class.

  3. Phil C.

    According to the “experts” in the 1960s, the planet was supposed to be in the grips of an ice age by 2000. Canada should now be under 1,000 feet of ice. It never happened. So, why should we believe these same self-styled “experts” now?

    By the way, I’m in California, and we’re living through the longest cold snap I can remember in the last 50 years — nearly a week of clear nights with freezing temperatures. The ciitrus industry already has losses in the millions of dollars. Maybe we need some more soot in the air to warm things up a bit.

  4. Dave Wilcox

    Why does this article use a picture of a row of parked Diesel trucks? Are we supposed to believe they’re the source of all of this mythical soot?

    When was the last time you saw a Diesel rig belching soot? Probably not in the last 20-25 years. Engines have become so clean and efficient in recent decades as the technology has improved that all I ever see coming from the stacks of Diesel tractors is hot, transparent gas, except for a small amount of soot for brief periods after a cold start or when they punch the throttle under heavy acceleration.

  5. Raj

    now i know why nothing ever happens to help global warming… idiots like the 4 who have commented up top.. they are the reason

  6. Bob

    @Raj-you are so right

  7. Brian

    @ Raj- They offered reasonable arguments. You offered nothing to the debate because you have nothing. Everything they stated was accurate. Soot is just carbon. The density of air at sea level is ~1.43g/L. Carbon Black (aka soot) has a density of ~2.0g/mL making it 1,398.6 times as dense as air. (Note that the density of air decreases as you go higher in altitude) You want me, a chemist, to believe that somehow Archimedes’ principle doesn’t apply in this situation? The global warming fanatics have an agenda and use pretend science to fit their predisposed outlook. They are an abomination to science.

  8. Scott

    I agree we are in some kind of global warming trend. It is great you found a problem but what is a solution, I heat my home with wood and not at all close to any gas line, If I went to propane for heat someone would have to drill for the extra gas that I would use, I can’t go electric as I live off the grid, and there is not enough sun light to go solar heating, So maybe it would be better if you bring up a problem you also offer some solution to the problem, and for your information Today truck which move our supply run very clean compared to years ago, We are cleaning up just maybe not fast enough for you

  9. Brent

    Raj, yes I agree with you sadly! These are the type of people who love driving around in their arrogant SUV’s and oversized trucks because they love their feelings of power, prestige, and self entitlement. They have no thought of really considering if this is true and doing the due diligence in an honest manner to find this out. They don’t care about the poor in places like Bangldesh who will be flooded out of their homes from rising sea levels or those in Africa or India who will suffer from devastating droughts and starvation . These are the same types who love their violent video games and stockpile of guns and ammunition, but bemoan gun control because they make up lies that the enormous stockpile of guns does not make it any easier for unbalanced, demon possessed people to hurt others. . When this drought comes home to places like the US and they suffer intractable, heat waves, wildfires and high food prices maybe then they will open their hearts and minds, but maybe not because the fool does not heed the warning signs of impending destruction and they stupidly tread towards is finality. God made us to be stewards of the earth, to love and help our fellow man, not to use the earth for hedonistic self indulgent lifestyles. They will answer to the Creator both in this life and the next, and should hear the call to repent and believe in the Savior and the Son of God who opens our eyes to truth, humility, love and wisdom to deal with these issues! Jesus Christ is Lord..

  10. Joseph Dillard

    Everyone has an opinion about global warming. Most are based on delusions, biases, fears, and financial considerations.
    Here’s a news flash: physics doesn’t do opinions. Thermodynamics doesn’t do opinions.
    Neither care.
    They don’t care about delusions, biases, fear, financial considerations, religion, science, human rights, life or death.
    They don’t have a damn thing to do with God, progress, justice, sin, karma, or salvation.
    They don’t care whether you are going to make or lose money on global warming.
    It’s like the law of gravity: if you want to ignore it; no problem. If you want to defy it for a while (go flying), no problem.
    Gravity doesn’t care and neither does atmospheric physics.
    The point?
    Ignorance makes both living and dying rather pathetic.

  11. Kelly

    Climate deniers: look around. Does the air seem clear, clean and unfettered view in all directions? No? That’s the evidence of man made activity.
    If you were to see the change in 20 year increments, the alteration of clean air is unmistakeable.
    Consider this:
    Hold a party tonight with just you and your wife. Decide to go to bed early, turn out the lights, go to sleep. Not a bad clean up in the morning. Couple of dishes, a pan or two, some napkins, just a small basin of dishes to wash.
    Tomorrow night: Your wife brings a friend, you bring one of your buddies. You decide to call it an early night and leave the cleanup till morning. Not so bad, a few more dishes, a little more work, not bad.
    Next night: Each of your friends bring another friend and you and your wife each bring a new friend to meet those people. Stay late, leave the clean up until morning. Following day, there are eight times as many dishes and pots. There were a lot more toilet flushes, hand-washes. More napkins, dish towels to wash. Clean up is a bigger deal.
    Following night for the next month: Every one brings a new guest and what do you think the mess is like? It’s not just your simple dinner party anymore and the clean up is a big affair.
    Go back and have a do-over. Make it a smoking affair, too. Not many climate deniers are going to be claiming they can’t smell the smoke in the couch, are they?

    So imagine someone coming over to your house and flushing the toilet 7-8 billion times. Throwing out a variety of disposables from razors to tampons to handwipes, you look at your house and soon realize nearly all of what YOU use is ‘disposable’…. 7-8 billion times. Daily. 7 days a week.

    The very narrow and naive view that if you cannot see it, it doesn’t exist; or that this plaent is a very big place and stuff happens; or this place is constantly changing… all of these ignore three very significant FACTS: 1) An overwhelming majority of scientists from all disciplines are in concurrence that temperatures are increasing 2) the evidence of man-made influences is also overwhelming, 3) the worst case scenarios for effects of those changes are quickly being reached and passed, 4) the risks of ignoring critical thinking on the topic, doing nothing are far more significant than the expense of doing something and being proved wrong.

    The amount of things which remain unknown are truly astounding, as we find out everyday. The foolishness of pretending that something doesn’t exist when evidence is presented, is perhaps the only more astounding thing.

  12. Infünity

    Soot is actually responsible for global dimming and cooling as a result of clouds having higher concentrations of reflective water droplets. Dust and radiation makes clouds and the sun has more to do with the change in temperature than soot or CO2. Just look at how all the other planets are heating up at the same rate as earth. Sunspot cycles…

  13. Eli

    Certainly doesn’t feel like its heating up. Its been insanely freezing cold lately. Record breaking cold.

  14. Hsaive

    So chemtrails are actually “SOOT”.?

  15. Hsaive

    Monetizing the climate is now big business. $14 Trillion in carbon “off-sets” even while Shindel et al have nailed “aerosols” as the chief driver of atmospheric warming.

    Geoengineering projects designed to melt polar ice have been the objective of industrialists for over 100 years. Since the Mid-90’s a global weather modification operation is now accelerating global ice melt and climate change to access resources.

    Read the amazing history of DELIBERATE GLOBAL WARMING and the joint military/federal agencies ongoing weather modification programs the media would rather you not consider. READ THIS

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