A long way from a record, the Alaska fire season is winding down at last with the long-term consequences far from clear.
The good news is no one died, although a number of firefighters suffered burns after falling into ash pits while battling the Swan Lake and McKinley fires in the Southcentral part of the state, according to state Division of Forestry spokesman Tim Mowry.
The latter fire also claimed 52 homes, three businesses and 84 outbuildings, according to the Matanuska-Susitna Borough. Meanwhile, the state’s largest city – caught between the Swan Lake fire to the south and the McKinley fire to the north – repeatedly suffered some of the worst air quality in the country.
Alaska in flames attracted plenty of media attention, too.
“‘Unprecedented’ wildfires ravage the Arctic,” CNN reported in June above a story reporting that “the fires themselves contribute to the climate crisis by releasing carbon dioxide (CO2) into the atmosphere.”
Only it’s not that simple, according to a variety of scientists, who contend fire history is regularly distorted by those who want to believe it another global warming/climate change disaster.
Wildfires, they point out, have long been a norm and apparently more so in the past than today.
Douglas Hamilton at Leeds University in the United Kingdom (UK) and others who took a long look at the history of fire in the geologic and historic records concluded, “fire occurrence increased to a peak around 1850…before declining to present-day levels. Paleoenvironmental archives therefore suggest that preindustrial fire activity was similar to present-day activity, if not higher. This runs contrary to existing ideas about the pristine nature of the Earth system in the preindustrial (period).”
“Fire is an essential component of the ecosystem and life has grown with it being present and thus incorporated it within its cycles,” Hamilton said in an email.
Despite a lot of hype about wildfires adding to CO2 in the atmosphere, they do not appear to play a major role in the build up the main greenhouse gas that keeps solar energy striking the earth from bouncing back into space as soon as the sun sets.
The Leeds study tracked fire history by looking for “black carbon,” ie. soot, in ice cores from glaciers to try to get a handle on past fires to determine the role of today’s fires in future global warming. When soot drifts into and deposits on areas normally covered with snow and ice, they began to absorb sunlight and store heat rather than immediately reflecting the solar energy back toward space.
Hamilton’s “reassessment of pre-industrial fire emissions” concluded current models for future climate over-estimate the effect of black carbon by ignoring its history. The study follows on another, which Hamilton pointed out, that concluded historical wildfire trends have also been widely miscalculated.
That study by Stefan H. Doeer and Cristina Santín at the United Kingdom’s Swansea University is titled “Global trends in wildfire and its impacts: perceptions versus realities in a changing world.” It was peer-reviewed and published by Royal Society Publishing – Biological Sciences in 2016.
“Human societies have coexisted with fire since their emergence,” Doeer and Santín wrote. “Yet many consider wildfire as an accelerating problem, with widely held perceptions both in the media and scientific papers of increasing fire occurrence, severity and resulting losses. However, important exceptions aside, the quantitative evidence available does not support these perceived overall trends. Instead, global area burned appears to have overall declined over past decades, and there is increasing evidence that there is less fire in the global landscape today than centuries ago.”
The misperceptions were broadly evident in Alaska this year.
The state was widely reported to be struggling with one of its “worst wildfire seasons” as parts of Alaska suffered through a drought and the warmest summer on record.
“Wildfires are a growing concern around the country. According to the latest National Climate Assessment, hotter, drier conditions over the past two decades have led to more area being burned across the U.S.”
The latter claim may be true of some parts of the U.S. in the past two decades, but the state forestry data indicates it is not the case in Alaska. It’s also a statement with which Doeer and Santín specifically took issue only three years ago, observing that “for the western USA, (records) indicate little change overall, and also that area burned at high severity has overall declined compared to pre-European settlement.”
The researchers noted societal views on fires in the Western world have been distorted since the “German forestry school of the nineteenth century” tried to eliminate wildfires as a waste of timber resources.
“Regarding social perceptions, it is important to stress that, in many of these regions, intentional burning had been used for a very long period both by native people and settlers,” they wrote. “Thus, in rural areas fire was understood as part of the landscape management culture. However, the current general public perception is predominantly different. Until very recently, governments refused to present fire as a potential positive ecological factor out of concern that any admission of a positive role for fire would sound contradictory. Smokey Bear in the USA is the best, but not the only, example of effective public awareness campaigns supporting 100 percent fire suppression.”
The Swansea researchers took to task both journalists and scientists, such as those this summer pushing the idea Alaska wildfires were somehow unique in state history because of drought in places.
“Numerous reports, ranging from popular media through to peer-reviewed scientific literature, have led to a common perception that fires have increased or worsened in recent years around the world,” Doeer and Santín wrote. “Where these reports are accompanied by quantitative observations, they are often based on short timescales and regional data for fire incidence or area burned, which do not necessarily reflect broader temporal or spatial realities.”
Mowry said Monday that just under 2.6 million acres of Alaska appear to have burned this year, “so we’re not anywhere near a record (almost 6.6 million in 2004).”
The 2019 number is about 600,000 acres less than burned in 1990 when the Alaska Division of Forestry started putting its fire reports online. This year’s toll is near double the 30-year average of 1.4 million acres, but it is within the middle of the range of fires in the three fire decades since 1990.
More significantly, the 2019 fire season is bringing to an end a decade in which the number of acres burned trails the 2000s by more than 5.5 million acres, according to the state data,
Decade-long or longer snapshots provide a more accurate picture of what is going on in any ecosystem than do annual snapshots. The latter are part of that “short timescale” problem referenced by Doerr and Santin.
An average of about 1-million-acres per year burned in Alaska in the ’90s within a range of 44,000 acres in 1995 to the 3.2 million acres in 1990, according to state records. The average in the first decades of the 2000s, however, mushroomed to 1.9 million acres as the years yo-yoed through time with a low of 104,000 acres burned in 2008 and the Alaska record burn of 6.6 million acres in 2004.
This decade looks as if it will slot in closer to 1990 than 2000 with an average burn of 1.3 million acres per year from a range of 234,000 acres in 2014 to 5.1 million in 2015.
Fire is a natural part of many of the state’s ecosystems and at least one of the most notable fires of ’19 – the 158,000-acre Swan Lake fire – blew up on the Kenai Peninsula where there has been considerable past fire suppression and in an area where a big fire has long been feared.
Almost two decades ago, the Kenai National Wildlife Refuge began warning of “fire hazards presented by large acreages of dead timber” in the area north of the Sterling Highway from Swan Lake west into the Kenai lowlands.
If this history of fire in Alaska is complicated, the relationship between wildfires and carbon dioxide (CO2) is only more so.
While trees are in flames they add CO2 to the atmosphere. There is no doubt about that given that CO2 and water are the main byproducts of all woodfires.
But new, fast-growing vegetation sucks more CO2 out of the atmosphere than mature vegetation, and some trees are better at storing CO2 than others. A study at Arizona State University found a large difference between deciduous trees which removed an average 80 kilograms (176 pounds) of carbon per year and coniferous trees, which removed only 41 pounds per year.”
There has been considerable speculation as to what happens to Alaska forests as the climate warms and the state continues to burns. Some scientists suggest a shift from highly flammable spruce trees to less flammable birch, popular and aspen trees, although scientists working in the field say they have observed no signs of that as of yet.
When researchers from the National Park Service and the University of Alaska Fairbanks went looking for these changes, about all they found was a general increase in tree growth apparently tied to warming.
“Our results confirmed expected increases in broadleaved species occupancy and abundance in the warmer, more fire‐affected study region along with considerably higher tree occupancy and abundance in high elevation areas there,” they reported in the peer-reviewed Ecological Monographs in May. “However, contrary to our predictions, we found no evidence of expected reductions in conifer occupancy or increases in non‐fire related tree mortality. Instead, both individual and combined tree species occupancy, density, abundance, and richness were considerably higher in the warmer, more fire‐influenced region, except in the warmest, driest areas (steep and south‐facing slopes at low elevation).”
And then there is the little matter of fire-driven carbon storage.
A study published in Nature Geoscience just last month concluded wildfires “convert a significant fraction of the burned vegetation biomass into pyrogenic carbon (ie., charcoal). Pyrogenic carbon can be stored in terrestrial and marine pools for centuries to millennia and therefore its production can be considered a mechanism for long-term carbon sequestration.”
“CO2 emitted during fires is normally sequestered again as vegetation regrows, and researchers generally consider wildfires to be carbon neutral events once full biomass recovery has occurred,” lead author Matthew Jones from the University of East Anglia in the UK told Science Daily.
“However, in a fire some of the vegetation is not consumed by burning, but instead transformed to charcoal. This carbon-rich material can be stored in soils and oceans over very long time periods.”
Jones and his colleagues concluded that over the long term fires are more of a carbon sink than the carbon source they were made out to be while Alaska was burning this year.
Jones classified the results of the study as “some good news,” saying the pyrogenic carbon is expected “to be trapped for a period of centuries to millennia, and although it will eventually return to the atmosphere as charcoal degrades, it is locked away and unable to affect our climate in the meantime.”
If you accept the global warming hypothesis – and there is no reason not to – that the steady increase in atmospheric CO2 since the start of the Industrial Age is tied to humans pulling increasingly large volumes of buried carbon out of the ground in the form of coal and oil; burning it; and in the process releasing large volumes of CO2 into the atmosphere, the idea that forests fires are generally carbon neutral only seems logical.
Lightning sparked fires have been common to many ecosystems for ages. Were they a large, net contributoe to atmospheric CO2, it would have been expected to spike upward before the Industrial Revolution, especially if one accepts the conclusion of Hamilton and colleagues who say the black-carbon record shows there were as many fires, or more, then as now.
But as with many things climate related, it’s complicated. Fire is simpler. If there are stockpiled forest fuels and tinder, as was the case on the Kenai, and lightning strikes, a fire will erupt. What happens after that depends on wind, weather, fire-fighting resources and management decisions.
Large parts of Alaska wilderness are considered “let-burn” areas where ecologists recognize the regenerative power of fires no matter how it might be portrayed as a new global-warming threat.