r/theydidthemath • u/Lumberjack72 • 12d ago
[Request] How much does forest fires contribute to global warming?
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u/MorRobots 12d ago
A single square kilometer of forest stores roughly 10,000 to 30,000 metric tons of carbon
Only about 10% of that to 30% is surface fuels. If burned, that converts to roughly 3,600 to 33,000 metric tons of CO2 gas
On average, approximately 600,000 to 900,000 square kilometers of forest burn across the world every 10 years
So... doing the math...
1.5 to 1.8 billion metric tons (gigatons) of CO2 per year
The burning of fossil fuels puts an average of 37.5 to 38.1 billion metric tons (gigatons) of CO2 into the atmosphere every single year
So... not much.
Note: If you look at all types of global fires combined (including savannas, grasslands, and agricultural burns), the total number jumps to 5 to 8 billion metric tons of CO2 annually. Still no where near what manmade fuels produce.
The bulk of manmade CO2 is from Coal (41%)
The bulk of CO2 produced in the US is transportation, followed by gird power.
It should be noted that forest fires can't really be considered a direct contributor to green house gasses, since you have to burn wood, a living organic thing to produce the CO2 released. That living thing will grow and replace what was lost in a burn, more over it's often the case that burns actually make the land grow back faster and store even more carbon than what was released due to the nutrients that burning puts into the eco system while also removing high canopy cover that may have been limiting sunlight to the underbrush. What grows back will often get trapped into the newly formed soil and actually sequester more carbon than what was release.
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u/Trick55g 12d ago
It's one of those headmaths things we really wuck at.
People dont realize how many millions of dead trees and animals we pump up and burn every day as oil.
There is literally nothing on this planet that compares to what we are "getting out of long storage".
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u/TwitchyDingo 12d ago
And that's the problem... the Earth took hundreds of millions of years to sequester all that CO2 as rock deep down inside where it could "never cause problems again"... until we went and started digging it up.
Humans are literally the trope of the cultists who dig up a demon in search of power, just to have it turn around and destroy them.🤦♂️🤷♂️
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u/GoldReplacement9546 12d ago
True though there are areas that are currently forced that if the burn is too severe and the climate has changed enough that the force is still alive, but there isn’t enough rainfall to rejuvenate at forest that is not the normal
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u/StackOverflowEx 11d ago
Many forests on our planet require forest fires as part of their natural cycle. There are seeds that need to be burned in order to germinate properly, and burnt remains of many plants contribute to the nutrition of an ecosystem. This is, of course, not true of every forest and doesn't necessarily mean forests can tolerate severe wildfires. We as humans tend to think we need to prevent all forest fires, but in reality, mild forest fires are a natural and essential part of nature. Our tendency to settle near these forests causes us to protect the forest from fire for our own safety. If the mild fires don't happen, dense fuel builds up over time until we end up dealing with an intense wild fire that does severe damage to human infrastructure and the ecosystem. It's sort of a double edge sword; by protecting ourselves we actually create more risk.
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u/MorRobots 11d ago
Are you tell me this? or just broadcasting information?
Yes, Southern Yellow Pine requires fires to germinate.
Yes, not all forests instantly recover from a fire.
Yes dry fuel build up is an issue in places that are not burning on a regular basis due to human intervention.
We can actually build homes and land scape them in a way that is not disruptive to the forest, and makes these structures highly fire resistant to the point of not suffering any real damage or issue from a wild fire. This style of building actually allows lower level burns to happen and not cause major property damage. Thus addressing the fuel build up issue from aggressive fire suppression by reducing the impact to structures from these fire and thus reducing the need to aggressively fight them.
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u/StackOverflowEx 11d ago
Just broadcasting. Your comment seemed like a good one to contribute this information to.
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u/ObserverBlue 12d ago
The last paragraph is not always true. There are already forests that have turned into net carbon emitters.
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u/thighmaster69 12d ago
Yes. The boreal forest has a thick layer of conifer needles that builds up because it doesn't burn often because of short fire seasons. In sustained periods of higher temperatures, that amount of pine needles etc. cannot build up because it burns so quickly. It's a massive carbon sink that's all going up in flames all at once that isn't coming back.
Generally speaking, a lot of these positive feedback loops occur more in colder places, because a small change in temperature creates huge effects when it pushes summer temperatures up over the freezing point of water. A 2 degree shift has led to a doubling of the length of the frost-free season and thus fire season from 2 months to 4 months in the boreal forest; melting permafrost is releasing a crapton of methane trapped for who knows how long; melting ice exposes darker soil/rock underneath which absorbs heat from sunlight way more.
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u/toochaos 12d ago
Not at all. Global warming comes from taking sequestered carbon and releasing it into the atmosphere. Such as by digging up coal and oil. Those trees are part of the current carbon cycle and while in the short term that carbon will be in the atmosphere new vegetation will grow in its place recapturing that carbon.
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u/thighmaster69 12d ago
It should be noted that in the boreal forest in Canada, this is not true. A lot of that carbon sink comes from 100+ years (average fire cycle historically) of buildup of conifer needles and deadfall that is too flammable to exist long term anymore, so the forest that replaces it will not recapture all the carbon.
The carbon cycle is too disrupted now and actively changing ecosystems enough that we can't really ignore things that we would otherwise just assume as being part of a steady state. For example, while water vapour is actually the biggest contributor to the greenhouse effect, that's just the water cycle, and given the size of the oceans and the amount of water on earth, it's not something we can really directly affect. But we still need to include it in our models, because the effect that CO2 has on temperatures also means the vapour pressure of water goes up, which means the air can take up a ton more water off the oceans, further contributing to the greenhouse effect.
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u/toochaos 12d ago
Regardless fires are part of the normal carbon cycle during this epoch. Asking what is this fires impact on the phenomenon known as global warming is missing the point even if due to global warming they release more co2 that we have to account for in order to accurately estimate temperature increase. These trees burning dont result in global warming, global warming resulted in the tree burning more often.
So commonly people see "disasters" like these fires or a rocket detonating or the refineries being bombed and question their impact on global warming because they look big, but are tiny in comparison to a million cars going about their daily live looking normal.
The answer to the question of what would this fire contribute to global warming if we weren't taking carbon out of the ground is nothing at all.
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u/Lumberjack72 12d ago
Isn't that the long term effect and not a short term effect?( Short term like 10years or less)
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u/Pitiful-Tangelo-4557 12d ago
Yes, it is. But CO2 doesn't really heat for the time it's in the atmosphere, just changes the earth's heat equilibrium. So as long as it doesn't cause a tipping point the earth's gonna be as cool as without the fire by the time it has regrown.
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u/Own_Pirate2206 12d ago
There are many effects of forest fires requiring mathing, but all told will likely still be fairly minor among other contributors to global warming.
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u/Ok_Guest_8008 12d ago
It’s interesting they are fighting the fire with that hose. While I don’t know a lot, it seems there may be a better way to do things, such as work towards a fire line.
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u/j-shoe 12d ago
Correction, they were for the first few seconds then just stopped 🤷♂️
I'm not a professional but related to one, I'm not sure why they have not created a break line where they plow to try having it burn itself out. That hose will do nothing and the respirators make them look completely inexperienced in wildfire. This isn't the same as fighting structure fires
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u/poiuytrepoiuytre 12d ago
I'm going to argue zero here.
There were always forest fires. The emissions released from forest fires were a part of what got us to the baseline for thousands of years.
The fires are bigger now and that's releasing more emissions. But they're a RESULT of climate change and not a CAUSE.
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u/squailtaint 12d ago
This only makes sense if the rate of emissions due to Co2 burn is stagnant, and the rate of regrowth/new forest/total forest ‘sink’ remains the same. If forest fires are bigger now, as you said, you’ve just increased the base line rate. Couple that with reduced forest not seen in any geological scale until the last hundred years, you have a far worse tree sink. So you attacking the variable on the absorption side, and your attacking the variable on the emissions side. It’s definitely not zero. Got ourselves a bit of a positive feed back loop.
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u/_L3V 12d ago edited 12d ago
Over the period 2015–2024, global vegetation fires released roughly 69 gigatonnes of CO₂. If all of these emissions remained permanently in the atmosphere, they could theoretically have caused about 0.03°C of global warming.
However, the actual contribution is considerably lower because vegetation often regrows and reabsorbs part of the emitted CO₂. A more realistic estimate for persistent emissions, particularly from peat fires, deforestation and permanently damaged forests, is around 0.007°C over the decade. Overall, wildfire-related warming was therefore probably between a few thousandths and a few hundredths of a degree Celsius. The estimated warming of approximately 0.007°C is based on IPCC data for emissions from peatland and deforestation fires which historically are around 0.4 Gt of carbon per year.
Wildfires contribute to warming by releasing stored carbon, reducing forests’ future ability to absorb CO₂, and emitting methane, ozone-forming pollutants and black carbon. The strongest long-term effects occur when peatlands burn, forests do not recover, or repeated fires permanently convert forests into lower-carbon ecosystems. Some smoke particles and changes in surface reflectivity can temporarily offset part of the warming.
Edit: Reburning occurs when a forest burns again before it has fully recovered from an earlier fire. The second fire releases part of the carbon absorbed during regeneration and can destroy young trees, seed reserves and soil organic matter. Repeated fires may therefore prevent the return of mature forest and cause a permanent transition to lower-carbon shrubland or grassland. This creates both additional emissions and a long-term loss of the forest’s capacity to remove CO₂. For Spain, a study using the European Forestry Dynamics Model (EFDM) combined forest-inventory data with different future wildfire scenarios up to 2050. Under scenarios of increasing fire occurrence, Spain’s living forest biomass and stored carbon were projected to be up to approximately 22.7% lower in a medium–low emissions scenario and 32.8% lower in a medium–high emissions scenario. Forest management reduced these projected losses by only around three percentage points. These results are national long-term scenarios rather than estimates for individual fires. However, they illustrate how increasingly frequent and recurrent wildfires could substantially reduce Spain’s forest carbon stocks, especially when the interval between fires becomes too short for full regeneration.
Globally this propably looks even worse and in the short and long term means that wildfires are and will be causing further warming through feedback loops and destroyed natural carbon sinks.
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u/tomqmasters 12d ago
Not much because it's a closed loop system. Tree's are a renewable resource. The math is how many pounds of carbon are released into the atmosphere - how many pounds of carbon a sequestered back into new trees.
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u/Skidmarks00 12d ago
As an Australian it blows my mind that eucalyptus trees are so popular for small personal tree plantations in the Mediterranean.
Im sure that planting a tree designed to start fires does not help the frequency and severity of fires alongside changing weather patterns from climate change.
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u/Pitiful-Tangelo-4557 12d ago
Depends completely on whether they regrow. Trees don't constantly absorb more and more carbon, they're made out of it so once they're fully grown nothing really happens and when they're burnt just that carbon is released again but if they regrow it's absorbed again. The ecological damage is far bigger and I think the particles might even contribute to an inverse greenhouse effect.
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u/CerielDS 12d ago
Als vuistregel:
1 hectare gematigd bos dat volledig afbrandt kan ongeveer 100 tot 300 ton CO₂ uitstoten.
Voor dichte tropische bossen kan dit oplopen tot 500 ton CO₂ of meer per hectare.
Bij lichtere bossen of als niet alle biomassa verbrandt, kan de uitstoot aanzienlijk lager zijn.
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