Volcanoes Can Affect Climate
Volcanic eruptions are responsible for releasing molten rock, or lava, from deep within the Earth, forming new rock on the Earth’s surface. But eruptions also impact the atmosphere.
The gases and dust particles thrown into the atmosphere during volcanic eruptions have influences on climate. Most of the particles spewed from volcanoes cool the planet by shading incoming solar radiation. The cooling effect can last for months to years depending on the characteristics of the eruption. Volcanoes have also caused global warming over millions of years during times in Earth’s history when extreme amounts of volcanism occurred, releasing greenhouse gases into the atmosphere.
Even though volcanoes are in specific places on Earth, their effects can be more widely distributed as gases, dust, and ash get into the atmosphere. Because of atmospheric circulation patterns, eruptions in the tropics can have an effect on the climate in both hemispheres while eruptions at mid or high latitudes only have impact the hemisphere they are within.
Below is an overview of materials that make their way from volcanic eruptions into the atmosphere: particles of dust and ash, sulfur dioxide, and greenhouse gases like water vapor and carbon dioxide.
Volcanoes can impact climate change. During major explosive eruptions huge amounts of volcanic gas, aerosol droplets, and ash are injected into the stratosphere. Injected ash falls rapidly from the stratosphere — most of it is removed within several days to weeks — and has little impact on climate change. But volcanic gases like sulfur dioxide can cause global cooling, while volcanic carbon dioxide, a greenhouse gas, has the potential to promote global warming.
Volcanic gases react with the atmosphere in various ways; the conversion of sulfur dioxide (SO2) to sulfuric acid (H2SO4has the most significant impact on climate.
Sulfate aerosols can cool the climate and deplete Earth’s ozone layer
The most significant climate impacts from volcanic injections into the stratosphere come from the conversion of sulfur dioxide to sulfuric acid, which condenses rapidly in the stratosphere to form fine sulfate aerosols. The aerosols increase the reflection of radiation from the Sun back into space, cooling the Earth’s lower atmosphere or troposphere.
Several eruptions during the past century have caused a decline in the average temperature at the Earth’s surface of up to half a degree (Fahrenheit scale) for periods of one to three years. The climactic eruption of Mount Pinatubo on June 15, 1991, was one of the largest eruptions of the twentieth century and injected a 20-million ton (metric scale) sulfur dioxide cloud into the stratosphere at an altitude of more than 20 miles. The Pinatubo cloud was the largest sulfur dioxide cloud ever observed in the stratosphere since the beginning of such observations by satellites in 1978. It caused what is believed to be the largest aerosol disturbance of the stratosphere in the twentieth century, though probably smaller than the disturbances from eruptions of Krakatau in 1883 and Tambora in 1815. Consequently, it was a standout in its climate impact and cooled the Earth’s surface for three years following the eruption, by as much as 1.3 degrees F at the height of the impact.
The June 12, 1991 eruption column from Mount Pinatubo taken from the east side of Clark Air Base.
The large 1783-1784 Laki fissure eruption in Iceland released a staggering amount more sulfur dioxide than Pinatubo (approximately 120-million ton vs. 20). Although the two eruptions were significantly different in length and style, the added atmospheric SO2 caused regional cooling of Europe and North America by similar amounts for similar periods of time.
Particles of Dust and Ash
Volcanic ash or dust released into the atmosphere during an eruption shade sunlight and cause temporary cooling. Larger particles of ash have little effect because they fall out of the air quickly. Small ash particles form a dark cloud in the troposphere that shades and cools the area directly below. Most of these particles fall out of the atmosphere within rain a few hours or days after an eruption. But the smallest particles of dust get into the stratosphere and are able to travel vast distances, often worldwide. These tiny particles are so light that they can stay in the stratosphere for months, blocking sunlight and causing cooling over large areas of the Earth.
Sulfur from Volcanoes
Often, erupting volcanoes emit sulfur dioxide into the atmosphere. Sulfur dioxide is much more effective than ash particles at cooling the climate. The sulfur dioxide moves into the stratosphere and combines with water to form sulfuric acid aerosols. The sulfuric acid makes a haze of tiny droplets in the stratosphere that reflects incoming solar radiation, causing cooling of the Earth’s surface. The aerosols can stay in the stratosphere for up to three years, moved around by winds and causing significant cooling worldwide. Eventually, the droplets grow large enough to fall to Earth.
Greenhouse Gases Emitted by Volcanoes
Volcanoes also release large amounts of greenhouse gases such as water vapor and carbon dioxide. The amounts put into the atmosphere from a large eruption doesn’t change the global amounts of these gases very much. However, there have been times during Earth history when intense volcanism has significantly increased the amount of carbon dioxide in the atmosphere and caused global warming.
Do the Earth’s volcanoes emit more CO2 than human activities? No.
Carbon dioxide (CO2) is a greenhouse gas and is the primary gas blamed for climate change. While sulfur dioxide released in contemporary volcanic eruptions has occasionally caused detectable global cooling of the lower atmosphere, the carbon dioxide released in contemporary volcanic eruptions has never caused detectable global warming of the atmosphere. In 2010, human activities were responsible for a projected 35 billion metric tons (gigatons) of CO2 emissions. All studies to date of global volcanic carbon dioxide emissions indicate that present-day subaerial and submarine volcanoes release less than a percent of the carbon dioxide released currently by human activities. While it has been proposed that intense volcanic release of carbon dioxide in the deep geologic past did cause global warming, and possibly some mass extinctions, this is a topic of scientific debate at present.
Published scientific estimates of the global CO2 emission rate for all degassing subaerial (on land) and submarine volcanoes lie in a range from 0.13 gigaton to 0.44 gigaton per year. The 35-gigaton projected anthropogenic CO2 emission for 2010 is about 80 to 270 times larger than the respective maximum and minimum annual global volcanic CO2 emission estimates.
There is no question that very large volcanic eruptions can inject significant amounts of carbon dioxide into the atmosphere. The 1980 eruption of Mount St. Helens vented approximately 10 million tons of CO2 into the atmosphere in only 9 hours. However, it currently takes humanity only 2.5 hours to put out the same amount. While large explosive eruptions like this are rare and only occur globally every 10 years or so, humanity’s emissions are ceaseless and increasing every year.
There continues to be efforts to reduce uncertainties and improve estimates of present-day global volcanic CO2 emissions, but there is little doubt among volcanic gas scientists that the anthropogenic CO2 emissions dwarf global volcanic CO2 emissions.
For additional information about this subject, please read the American Geophysical Union’s Eos article “Volcanic Versus Anthropogenic Carbon Dioxide” written by USGS scientist Terrence M. Gerlach.
Iceland’s Eyjafjoell volcano is emitting between 150,000 and 300,000 tonnes of carbon dioxide (CO2) per day, a figure placing it in the same emissions league as a small-to-medium European economy, experts said on Monday.
Assuming the composition of gas to be the same as in an earlier eruption on an adjacent volcano, “the CO2 flux of Eyjafjoell would be 150,000 tonnes per day,” Colin Macpherson, an Earth scientist at Britain’s University of Durham, said in an email. Patrick Allard of the Paris Institute for Global Physics (IPGP) gave what he described as a “top-range” estimate of 300,000 tonnes per day. Both insisted that these were only approximate estimates. Extrapolated over a year, the emissions would place the volcano 47th to 75th in the world table of emitters on a country-by-country basis, according to a database at the World Resources Institute (WRI), which tracks environment and sustainable development. A 47th ranking would place it above Austria, Belarus, Portugal, Ireland, Finland, Bulgaria, Sweden, Denmark and Switzerland, according to this list, which relates to 2005. Experts stressed that the volcano contributed just a tiny amount – less than a third of one percentage point – of global emissions of greenhouse gases.
When Mount Pinatubo erupted in the Philippines June 15, 1991, an estimated 20 million tons of sulfur dioxide and ash particles blasted more than 12 miles (20 km) high into the atmosphere. The eruption caused widespread destruction and loss of human life. Gases and solids injected into the stratosphere circled the globe for three weeks. Volcanic eruptions of this magnitude can impact global climate, reducing the amount of solar radiation reaching the Earth’s surface, lowering temperatures in the troposphere, and changing atmospheric circulation patterns. The extent to which this occurs is an ongoing debate.
Large-scale volcanic activity may last only a few days, but the massive outpouring of gases and ash can influence climate patterns for years. Sulfuric gases convert to sulfate aerosols, sub-micron droplets containing about 75 percent sulfuric acid. Following eruptions, these aerosol particles can linger as long as three to four years in the stratosphere.
Major eruptions alter the Earth’s radiative balance because volcanic aerosol clouds absorb terrestrial radiation, and scatter a significant amount of the incoming solar radiation, an effect known as “radiative forcing” that can last from two to three years following a volcanic eruption.
“Volcanic eruptions cause short-term climate changes and contribute to natural climate variability,” says Georgiy Stenchikov, a research professor with the Department of Environmental Sciences at Rutgers University. “Exploring effects of volcanic eruption allows us to better understand important physical mechanisms in the climate system that are initiated by volcanic forcing.”
Stenchikov and Professor Alan Robock of Rutgers University with Hans Graf and Ingo Kirchner of the Max Planck Institute for Meteorology performed a series of climate simulations that combined volcanic aerosol observations from the Stratospheric Aerosol and Gas Experiment II (SAGE II) available from NASA’s Atmospheric Science Data Center (ASDC), with Upper Atmosphere Research Satellite (UARS) data from NASA’s Goddard Earth Science Data and Information Services Center (GES DISC).
The research team ran a general circulation model developed at the Max Planck Institute with and without Pinatubo aerosols for the two years following the Pinatubo eruption. To study the sensitivity of climate response to sea surface temperature, using data from NASA’s Physical Oceanography Distributed Active Archive Center (PO.DAAC), they conducted calculations with climatologically mean sea surface temperature, as well as with those observed during particular El Niño and La Niña periods.
By comparing the climate simulations from the Pinatubo eruption, with and without aerosols, the researchers found that the climate model calculated a general cooling of the global troposphere, but yielded a clear winter warming pattern of surface air temperature over Northern Hemisphere continents. The temperature of the tropical lower stratosphere increased by 4 Kelvin (4°C) because of aerosol absorption of terrestrial longwave and solar near-infrared radiation. The model demonstrated that the direct radiative effect of volcanic aerosols causes general stratospheric heating and tropospheric cooling, with a tropospheric warming pattern in the winter.
“The modeled temperature change is consistent with the temperature anomalies observed after the eruption,” Stenchikov says. “The pattern of winter warming following the volcanic eruption is practically identical to a pattern of winter surface temperature change caused by global warming. It shows that volcanic aerosols force fundamental climate mechanisms that play an important role in the global change process.”
This temperature pattern is consistent with the existence of a strong phase of the Arctic Oscillation, a natural pattern of circulation in which atmospheric pressure at polar and middle latitudes fluctuates, bringing higher-than-normal pressure over the polar region and lower-than-normal pressure at about 45 degrees north latitude. It is forced by the aerosol radiative effect, and circulation in winter is stronger than the aerosol radiative cooling that dominates in summer.
NASA’s Upper Atmosphere Research Satellite (UARS) enables study of the chemistry, dynamics and energy balance in the atmosphere layers above the troposphere. UARS provides near-global (-80 degrees to +80 degrees) measurements of the atmospheres’ internal structure as well as measurements of external influences acting on the upper atmosphere. These measurements are made simultaneously in a coordinated manner. The UARS dataset spans from September 18, 1991 through August 31, 1999. UARS data are available from GES DISC.
SAGE II, launched in October 1984, uses a technique called solar occultation to measure attenuated solar radiation and to determine the vertical distribution of stratospheric aerosols, ozone, nitrogen dioxide, and water vapor around the globe. SAGE II data are available from ASDC.
Multi-Channel Sea Surface Temperature (MCSST) data are derived from measurements of emitted and reflected radiance by the five-channel Advanced Very High Resolution Radiometers (AVHRR) onboard the NOAA -7, -9. -11 and -14 polar orbiting satellites. MCSST data currently extend from November 11, 1981 through June 7, 2000, and are updated as new data become available. The sea surface temperature data sets may be ordered from PO.DAAC.
Man-made, or “anthropogenic” emissions can make the consequences of volcanic eruptions on the global climate system more severe, Stenchikov says. For instance, chlorofluorocarbons (CFCs) in the atmosphere start a chain of chemical reactions on aerosol surfaces that destroy ozone molecules in the mid-latitude stratosphere, intensifying observed stratospheric ozone depletion.
“While we have no observations, the 1963 Agung eruption on the island of Bali probably did not deplete ozone as there was little atmospheric chlorine in the stratosphere. In 1991 after the Pinatubo eruption, when the amount of CFCs in the stratosphere increased, the ozone content in the mid-latitudes decreased by 5 percent to 8 percent, affecting highly populated regions,” says Stenchikov.
NASA and the National Science Foundation have funded Robock and Stenchikov to study the Pinatubo eruption in more detail, and to conduct another model comparison with the volcanic aerosol data set. They plan to combine SAGE II data with available lidar and satellite data from various DAACs to improve their existing data set.
By understanding the impact of large volcanic eruptions on Earth’s climate system in more detail, perhaps scientists will be in a better position to suggest measures to lessen their effects on people and natural resources.
In brief: How much do volcanoes influence the climate?
Overnight, a volcano in Iceland called Bardabunga began erupting, triggering a flurry questions about the possible impacts for the UK and further afield.
In 2010, EyjafjallajÃ¶kull eruption in Iceland disrupted global transport – shutting down air traffic across Europe for several days.
Volcanoes also have an effect on the climate. Throughout earth’s history, volcanic eruptions have punctuated the temperature record. We take a quick look at the role of volcanic eruptions in climate – past, present and future.
A tiny contribution to global warming
Volcanic eruptions can affect climate in two main ways. First, they release the greenhouse gas carbon dioxide, contributing to warming of the atmosphere.
But the warming effect is very small. Volcanic carbon dioxide emissions since 1750 are at least 100 times smaller than those from fossil fuel burning, according to the latest report from the Intergovernmental Panel on Climate Change (IPCC).
A two-year cooling effect
As well as carbon dioxide, volcanic eruptions also blast a cloud of ash, dust and sulphur dioxide into the stratosphere, which is quickly blown around the globe.
Sulphur dioxide combines with oxygen and water to form sulphuric acid “aerosols”. These particles directly reflect sunlight and encourage clouds to form.
This cooling effect outweighs the warming contribution from carbon dioxide, causing an overall cooling that tends to lasts for about two years after a major eruption.
The eruption of Mount Pinatubo in 1991 was one of the century’s most powerful eruptions. Its huge dust and aerosol cloud cooled parts of the world by up to 0.4 degrees Celsius.
There have been no significant eruptions since Mt Pinatubo in 1991, though a few small events caused fairly significant cooling in the first decade of the 21st century. The 2010 EyjafjallajÃ¶kull eruption’s effect on climate was about 10,000 times less than Mount Pinatubo.
Short term impacts, but no lasting effect
Overall, volcanic eruptions have had very little influence on the temperature changes we’ve seen in the last century, except for the brief period following an eruption.
Along with other natural variability, such as ocean cycles and changes in the sun’s activity, volcanic eruptions contribute to ups and downs in global temperature from year to year.
Scientists think the cooling effect of volcanic eruptions together with a drop in solar activity since about 2005 is one reason why temperatures at earth’s surface have risen slower in the last 15 years than previous decades, for example.
Scientists expect some large eruptions this century but can’t predict when.
Since any contribution to global temperature will be small compared to human sources, all IPCC’s forecasts for future warming assume no major volcanic eruptions.
Based on greenhouse gas emissions alone, the IPCC expects between 0.3 and 0.7 degrees Celsius temperature rise by 2016-2035 compared to 1986-2005.
Consequences for Europe
While volcanic eruptions don’t have a lasting effect on global climate, evidence suggests summers in Central Europe immediately following a major eruption are cooler and drier than usual. By contrast, winters in Northern Europe tend to be warmer and wetter.
Earlier this week, The Daily Express this week suggested a different – and rather more dramatic – outcome, saying:
“Britain could freeze in years of super-cold winters and miserable summers if the Bardarbunga volcano erupts, experts have warned.”
The Met Office says the impacts specifically for Britain have a lot to do with which direction the winds is coming from when the volcano erupts. At the moment, the Bardabunga eruption hasn’t produced an ash cloud, but scientists are monitoring it closely for further activity.
Geoengineering the climate
Volcano eruptions provide an insight into what would happen if we deliberately inject aerosols into the atmosphere. This has been suggested by some as a way to “geoengineer” the climate to bring global temperatures down.
Research suggests the impact on the global water cycle is likely to be large. Both the African and Asian monsoons were weaker in the year following the Mt Pinatubo eruption in 1991.
How wildfires affect climate change — and vice versa
As the 2021 wildfire season begins to unfold, the memories of past seasons linger — in the lungs of people, in the communities and landscapes that burned and in the atmosphere, where greenhouse gases from wildfires continue to warm our planet.
Wildfires wreaked havoc across the world over the past year. In Australia, bushfires spanning 2019-20 captured public attention as videos of scorched koalas and wallabies made the rounds on the internet.
Fires burned in Arizona and Colorado during the early waves of COVID-19. In Siberia, boreal forests and tundra fires burned in the far north. And as fall arrived, Washington and Oregon began to burn, with the consequences felt across the United States and into Canada as smoke and COVID-19 kept people indoors.
When it comes to climate, wildfires occupy an unusual space: they are driven by climate change and they help drive it. As this vicious cycle plays out and predictions of extreme future fire seasons continue, the need for human intervention to interrupt this cycle has never been more clear.
Greenhouse gas release
Climate change is raising average global temperatures, bringing with it longer droughts, with cascading effects for forests and wildfires. These impacts are highly place-dependent — they are determined by the ecology an ecosystem and its history of disturbance, like wildfires, insect outbreaks or logging.
Across many forest types, increasing temperatures and droughts dry out fuels, including vegetation like dead trees and fallen branches, more quickly and completely, priming them to burn.
It’s complicated: While CO2 causes long-term warming, aerosols can have both a warming and a temporary cooling effect.
The extreme wildfires sweeping across parts of North America, Europe and Siberia this year are not only wreaking local damage and sending choking smoke downwind. They are also affecting the climate itself in important ways that will long outlast their flames.
Wildfires emit carbon dioxide and other greenhouse gases that will continue to warm the planet well into the future. They damage forests that would otherwise remove CO2 from the air. And they inject soot and other aerosols into the atmosphere, with complex effects on warming and cooling.
To be sure, the leading cause of global warming remains overwhelmingly the burning of fossil fuels. That warming lengthens the fire season, drying and heating the forests. In turn, blazes like those scorching areas across the Northern Hemisphere this summer have a feedback effect—a vicious cycle when the results of warming produce yet more warming.
Although the exact quantities are difficult to calculate, scientists estimate that wildfires emitted about 8 billion tons of CO2 per year for the past 20 years. In 2017, total global CO2 emissions reached 32.5 billion tons, according to the International Energy Agency.
When they calculate total global CO2 output, scientists don’t include all wildfire emissions as net emissions, though, because some of the CO2 is offset by renewed forest growth in the burned areas. As a result, they estimate that wildfires make up 5 to 10 percent of annual global CO2 emissions each year.
There have always been big wildfires, since long before humans began profoundly altering the climate by burning fossil fuels. Those historical emissions are part of the planet’s natural carbon cycle. But human activities, including firefighting practices, are resulting in bigger, more intense fires, and their emissions could become a bigger contributor to global warming.
Extreme fires can release huge amounts of CO2 in a very short time. California fire experts estimate that the blazes that devastated Northern California’s wine country in October 2017 emitted as much CO2 in one week as all of California’s cars and trucks do over the course of a year. This year’s fires have also been extreme; two of the state’s largest fires on record are burning right now, including the Mendocino fire complex, which exceeded 400,000 acres this week.
According to NOAA scientist Pieter Tans, head of the carbon cycle greenhouse gases group with the Greenhouse Gas Reference Network, a very large, very hot fire destroying 500,000 acres could emit the same total amount to CO2 as six large coal-fired power plants in one year.
That suggests that California’s wildfires in recent years may be releasing enough CO2 to endanger the state’s progress toward meeting its greenhouse gas reduction targets.
While fires have been worsening in some regions, globally the total burned area and emissions from wildfires have actually decreased over the past 20 years, said Guido van der Werf, a Dutch researcher who analyzes trends for the Global Fire Emissions Database. The global decline is because burned savannas and rainforests in the tropics are being converted to agricultural lands, which are less fire-prone.
In regions of the world drying out with global warming, like the U.S. West and the Mediterranean, however, extreme fire seasons have increased in recent years.
“If we start to see a higher level of fire activity than in the past because of global warming, they become part of a climate feedback loop,” van der Werf said. That means warming causes more fires, which causes more warming.
In some forests in California and British Columbia, climate impacts can reduce snowpack and speed up spring snow melt, which can lead to even drier vegetation and increase fire risk. In ecosystems plagued by drought, like areas of the southwestern U.S., long stretches without rain can kill trees and leave dead wood ready to burn.
As a driver of climate change, wildfires release huge quantities of greenhouse gases to the atmosphere. In British Columbia, extreme fire years in 2017 and 2018 each produced three times more greenhouse gases than all other sectors of the province combined. While trees can and do regrow after fire, building back carbon takes time, which is precisely what we lack in the fight against climate change.
In addition to their CO2 emissions, wildfires can affect the climate in other important ways.
Dead Wood and Changes to the Land
Fires don’t just burn up trees and shrubs and emit smoke. They leave behind long-lasting changes on the ground, and those changes also have effects on the climate.
Over the course of several decades after a big fire, emissions from decomposing dead wood often surpass by far the direct emissions from the fire itself. But at the same time, new growth in burned areas starts to once again take CO2 from the atmosphere and store it.
Fires also change the reflectivity of the land, called albedo. As burned forest areas start to regrow, lighter-colored patches of grasses and shrubs come in first, which, because they reflect more solar radiation, can have a cooling effect until the vegetation thickens and darkens again.
Scott Denning, an atmospheric scientist at Colorado State University, says site-specific studies show that the cooling effect in northern forests can last for decades. In a tropical rainforest, on the other hand, the dark canopy can regrow within a few years.
When new trees grow fast, they can start stashing away significant amounts of carbon quickly. But some recent research suggests that global warming is preventing forest regrowth after forest fires, including along the Front Range of Colorado and in the forests of the Sierra Nevada. If that emerges as a widespread trend in the coming decades, it means less forests available to take CO2 out of the atmosphere. Forests are estimated to absorb up to 30 percent of human greenhouse gas emissions.
That’s not to say that climate change is the only thing driving massive wildfires, nor is greenhouse gas release the only consequence. People, specifically European colonizers in North America, have created and perpetuated conditions that increase the risk of large, severe fires. We are just one of many species that suffer from the consequences.
An interrupted fire cycle
Fire has long played an important role in maintaining the health of many types of forest. For example, lodgepole pine relies on fire to reproduce by melting the resin that releases its seeds.
In the early 20th century, bans on controlled Indigenous burning and policies of fire suppression interrupted the fire cycle with which forests evolved, and removed regularly occurring fires from forested areas.
The exclusion of fire from temperate landscapes has disrupted the mosaics of ecosystems and recently burned areas that had once moderated fire spread and behaviour. Logging and timber practices, like clear cutting and replanting, have also modified fire risk by favouring stands of coniferous trees nearly identical in age that can quickly carry and spread fire.
Aerosols’ Cooling and Warming Effects
Scientists can’t say for certain whether the global level of fire activity in recent years is warming or cooling the atmosphere overall. Part of the reason that they don’t have a definitive answer is because, along with CO2, wildfires also produce many other volatile organic particles called aerosols, including substances like black carbon and gases that form ozone.
One recent study suggests that wildfires emit three times more fine particle pollution than estimated by the Environmental Protection Agency. This pollution creates health problems, and scientists are also working to better understand its impact on the climate.
Some of those aerosols can make the atmosphere more reflective. They block sunlight, which cools the atmosphere, similar to the effect attributed to emissions from volcanic eruptions. In general, the climate effect of aerosols is short-lived, lasting from a few months to a couple of years.
But black carbon, an aerosol and short-lived climate pollutant, can actually absorb heat while floating around in the air, and that heats the atmosphere. Recent research shows that the heat-trapping potency—though it is short-lived—is much higher than previously thought, roughly two-thirds that of carbon dioxide, according to Alfred Wiedensohler, with the Leibniz Institute for Tropospheric Research.
Megafires may intensify these emissions and send them higher into the atmosphere. A study published this week found that wildfires in Canada in 2017 resulted in extreme levels of aerosols over Europe, higher than those measured after the 1991 Mt. Pinatubo eruption.
An increase in megafires, driven at least partly by global warming, could change the wildfire carbon cycle, said Mark Parrington, a senior scientist with the European Centre for Medium-Range Weather Forecasts Copernicus Atmosphere Monitoring Service.
“In general, if we’re seeing an increase in megafires, with direct injections (of pollutants) into the upper atmosphere, the effects can linger for weeks or months, and that could have more of a climate-cooling effect,” he said.
More pieces to the wildfire-climate puzzle will fall into place after scientists evaluate data gathered by a C-130 airplane that’s making daily cruises near Western U.S. wildfires to take detailed measurements of wildfire emissions. The mission is sponsored by the National Center for Atmospheric Research and the National Science Foundation.
With the explosion of wildfires in the region the past few decades, the data will help evaluate impacts to human health and the environment, including nutrient cycling, cloud formation and global warming, said University of Wyoming atmospheric scientist Shane Michael Murphy, one of the project researchers.
Wind-Blown Soot Can Affect the Ice Sheets
Eventually, the skies will clear once again, but all that smoke doesn’t just magically disappear. The CO2 will heat the atmosphere for centuries; the methane for a few decades. Some of the aerosols and other particles are heavy enough to drift earthward, and others will wash to the ground with the first good rains of autumn or winter, but not before spreading out over the Northern Hemisphere’s oceans and continents.
The overall effect of wildfire fallout on Arctic melting is difficult to quantify, partly because of sparse sampling across the remote area, and partly because of the great annual variations in wildfire emissions. But a growing body of research suggests that wildfire soot will contribute to accelerating the Arctic meltdown in the decades ahead.
After doing research on the subject, I have come to the conclusion that I am comparing apples and oranges when I asked the question does Volcanoes or Forest Fires produce mor CO2? While, both are devestating in their own right. Volcanoes tend to be the lesser of two evils. Volcanoes produce little CO2 but they do infact produce a great deal of particulate matter which can remain in the atmosphere for quite some time. This can cause global cooling rather than the global warming that increased CO2 emissions causes. Take for example when the Indonesian volcano, Mount Tambora erupted in 1816. It was the greatest volcanic eruption in recorded history. When it erupted the climate went berserk. The winter brought extreme cold, and torrential rains which unleashed massive flooding in Asia. Western Europe and North America experienced a ‘year without a summer’, while failed harvests in 1817 led to the ‘year of famine’. However, once the heavier than air particles finally settled back to earth, the catastrophe was over.
This is not the case with increased CO2 production. That is why large forest fires are so devastating. Not only does the fire produce large amounts of CO2, the death of millions of trees reduces the CO2 absorptive capabilities of the planet. This also causes a decrease in the byproduct of the CO2 obsorption which is oxygen. So a forest fire is essentially a triple threat. A threat that does not go away until the excess CO2 is finally absorbed. If we allow the production of CO2 to go unabated we only have to look to Venus for a real life example of the Green House Effect on steroids.
usgs.gov, “Volcanoes Can Affect Climate.”; insiderclimatenews.org, “How Wildfires Can Affect Climate Change (and Vice Versa),” By Bob Berwyn; scied.ucar.edu, “How Volcanoes Influence Climate.”; eartdata.nasa.gov, “Volcanoes and Climate Change: Large-scale volcanic activity may last only a few days, but the massive outpouring of gases and ash can influence climate patterns for years.” By Jason Wolf; theconversation.com, “How wildfires affect climate change — and vice versa.” By Carly Phillips;