Humans brought the heat. Earth says we pay the price
Amid wildfire death and destruction, there are solutions, workable smart solutions, but who wants to talk about that?
Out of the frying pan, into the fire
Heatwaves don't just fry the innards of us puny humans, they also desiccate and roast the world in which we live.
As recent conflagrations in Canada (2023 and 2024), the Northwestern US (2024), Australia (2019-2020), Siberia (2021, 2022, 2023, and 2024), and of course the Lahaina, Hawaii fire in 2023 and the Los Angeles, California disaster that stunned a nation this month, have amply shown, parched grasslands and boreal forests can host savage wildfires, resulting in the ruination of thousands of square kilometers of devasted wilderness, thousands of incinerated structures in living and working communities, and the deaths of not only millions of animals but also of scores of our fellow humans.
There are, of course, some climate-change denialists who argue, "But there have always been wildfires, just like there have always been changes in the Earth's weather. What's new?" Danielle Touma, research assistant professor at the University of Texas Institute for Geophysics, decided to find out, using the tool any objective, curious person would employ: Good ol' science.
Presenting the results of her research at AGU24, Touma removed any suspense in the title of her talk: "Changes in mean climate and climate variability drive substantial increases in extreme fire weather in the western United States" — or, to paraphrase James Carville's famous advice to Bill Clinton when that unknown Arkansas Governor ran for US President in 1992: "It's the climate change, stupid."
But are those fires destroying human habitations because we humans are moving into more-vulnerable areas, or because the fires themselves are growing in size and ferocity and thus reaching more into already habitable spaces? Moji Sadegh, associate professor of civil engineering at Boise State University, proposed a simple question at AGU24: "What we want to know is whether people are moving to areas that burn later, or is it that fires are encroaching upon existing human populations."
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To answer that deceptively simply query, Sadegh studied wildfire and damage data in the contiguous United States during the past two decades, the locations and population changes in the affected areas, and discovered that only one-fourth of the increasing trend in population exposure to wildfire damage was due to the increase in what he describes as people "moving to areas that burn later." Simply put, his research showed that three-quarters of wildfire damage to humans, their homes, and their businesses have not been due to said humans moving into fire zones, but instead due to fires growing more frequent, larger, and more destructive — and that increases to about 80 percent in the fire-prone Western United States.
Perhaps more concerning — though not surprising — were the findings by Sadegh and his colleague Arash Modaresi Rad, published in a 2023 paper in ScienceAdvances, based on research during the same period that compared destructive wildfires in the US states of Oregon, Washington, and California. They discovered that as wildfire damage "increased substantially" during that period, its catastrophic effects skyrocketed by nearly 250 percent for people "with high social vulnerability" — aka, the poor, the old, the disabled. What's more, the percentage of highly vulnerable residents affected by wildfires was not constant over many decades, but instead increased "at a very large rate" during the 2000–2021 period studied.
In traditionally cool scientific language, Sadegh and Modaresi Rad conclude, "Our results emphasize the importance of integrating the vulnerability of at-risk populations in wildfire mitigation and adaptation plans." Oh, and if you're interested in the raft of data underlying their conclusions, knock yourself out at Boise State's Joint Fire Science Program website.
Intuitively, there is a well-known relationship between extreme heat and wildfires
But are wildfires really caused by climate change and heatwaves? That sounds like a straightforward correlation — but, hey if there's any scientific cliché that bears repeating, it's that correlation does not imply causation™.
James Randerson, professor of Earth system science at the University of California at Irvine, hinted at that concern at AGU24, saying, "Intuitively, there is a well-known relationship between extreme heat and wildfires," citing the heatwave and fires of 2010 in the Russian Federation, plus other such recent heat-fire mashups in the Amazon, Australia, and Western North America.
But as Randerson well knows, "intuitively" is hardly a data-supported and evidence-based scientific linchpin. So to find support for that understandable intuition, Randerson and his colleagues began "quantifying wildfire response to extremes in fire weather" — the title of his AGU24 presentation.
Randerson and his team focused their analyses on 44 global study areas as defined by the IPCC's Sixth Assessment report (better known simply as AR6) and examined in each area the length and severity of heatwaves along with the number and size of wildfires and the type of terrain burned during each area's three-month peak fire season, which as Randerson explained: "Usually corresponds to the warmest time of the year, in most cases."
Their analysis showed a clear temporal link between heatwaves and the growth and size of wildfires. In addition, they established forest fires are more sensitive to the effects of heatwaves than shrub and grassland fires, and that among forests, boreal forests are more sensitive than forests in temperate or tropical regions. Boreal forests, for you non-dendrologists or xylologists, lie mostly in the high northern latitudes, cover between 11 and 12 percent of the Earth's landmass, and are comprised mostly coniferous trees such as pines, firs, spruce, and the like.
Unintuitively, Randerson suggested, was that although more individual fires were incited by heatwaves, the area burned by each of those individual fires was not necessarily greater than that of fires in non-heatwave situations. Although the total area burned during heatwaves was indeed larger, that extensiveness was due both to more individual fires and to those fires joining up into massive multi-ignition conflagrations, as was true in the boreal Russian Federation and associated pan-Arctic Canadian fires.
So what causes these multi-ignition monsters? Are they simply the result of heatwave-induced weather? It's not that simple, says Randerson. In some non-trivial number of cases the fires themselves create their own thunderstorms, which cause more lightning, which causes more ignition points, which cause more fires, which cause more thunderstorms, which cause ... well, you get the point. [cf. Ouroboros, above — ed.]
Those fire-caused thunderstorms, by the way, are known by the wonderful tongue-twisting term cumulonimbus flammagenitus, often referred to in the literature as the far more palatable pyro-Cb. It should be noted also that pyro-Cb storms make aerial fire-suppression assistance by helicopters and fixed-wing aircraft vastly more dangerous and often simply impossible.
The more heatwaves, the more fires. The more fires, the more pyro-Cb activity. The more pyro-Cb activity, the more ignition points. The more ignition points, the larger linked-up fires grow. The larger these linked-up fires grow, the more devastation. Game, set, match.
Our final bottom lines: Global warming exacerbates heatwaves. Heatwaves are increasing. Heatwaves kill. Heatwaves are worse for the poor and disabled. And heatwaves exacerbate wildfires.
So perhaps we should slow and eventually reverse global warming and its evil twin climate change by aggressively transitioning our economies from being based on fossil fuels to a reliance on clean energy, thus alleviating rising temperatures and lessening the increasing number of heatwaves, deaths, and fires. Deal?
Anthropogenic climate change is a problem — a real, quantifiable, demonstrable, and most importantly solvable problem. Luckily, we humans are smart. We’re inventive. We’re innovative. We can fix it — if we hurry. ®
Bootnote
You may have heard some foofaraw in recent news about how climate scientists don't know exactly why the Earth is heating as quickly as it quite demonstrably is. This minor niggle doesn't mean that climate models are crap.
It merely means that those models have been a bit too conservative, and that there are likely climatological elements that haven't yet been taken fully into account.
Think of it this way: A distiller aims to produce an 88-proof whisky, but his hydrometer shows his batch to be 90 proof. No matter; that usquebaugh (that's "red-eye" to us Yanks) may not have been foreseen, but it will still knock you on your bum.
PS: A number of US federal government websites tracking climate science, as well as healthcare issues including HIV prevention, were reportedly down as of Friday under the Trump administration's direction.