California has always dealt with significant, sometimes catastrophic wildfires. Yet the past couple of years at least have seemed dramatically different in terms of the number, frequency, speed, intensity and effects of fires on California populations. Since the onset of the Camp Fire in northern California and the Woolsey and Hill fires in Southern California over the past weeks, several prominent voices from the scientific and policy communities have weighed in with analysis of what’s happening and where the trends might be headed.
How Much of a Factor is Climate Change?
The most common refrain heard in recent commentary on the California fires is that the climate is changing faster and more pervasively than our social systems or thought processes have been able to adapt. In the case of wildfires what this means is that over time the weather is consistently getting hotter and drier for longer durations than we have figured out what to do with socially.
According to an analysis by Robert Rohde, the chief scientist at Berkeley Earth, the long-term tendency is clear: California’s fire season has migrated steadily from being ordinarily cool and wet at the beginning of the last century, towards a current state of being normally hot and dry. As these consecutive hot and dry years accumulate the likelihood that vegetation becomes susceptible to sparks, and that the resulting blazes quickly consume large amounts of vegetated land goes steadily up.
Rohde’s conclusions are supported by a recent interview with UCLA climate scientist Daniel Swain who argues the fires are driven by the confluence of wind, excessive heat and dryness, indirectly driven by long-term climate trends. “Part of what we’ve been seeing with all of these big fires is there are two big weather or climate factors at play—very strong offshore winds, which in California can be extremely strong in localized canyons, especially along the western slopes of the Sierra Nevada and the canyons of coastal areas, where both of the fires are now burning. Those really strong winds can push a fire extremely quickly. The other part is what the vegetation is actually like. How dry is it? If it is at summer-like dryness levels, as it is now, then that fire is going to behave much differently than if we had experienced the rain that we typically experience come beginning of November. There is the primary climate connection. What’s really happening is an indirect effect, but a powerful one through the dryness of the landscape and dryness of the vegetation.”
Analysis from Yale Climate Connections expands on possible climate change connections blowing in the winds. Citing a 2006 paper in Geophysical Research Letters, they argue that the famed hot and dry Santa Ana winds are pushing steadily later in the year towards the winter, expanding the annual risk period for southern California in significant ways. Likewise, disappearing sea ice in the Arctic due to increased global warming has tended to disrupt the jet stream, the primary wind pattern regulating temperature and moisture in the northern hemisphere. Drastic changes underway in the Arctic are leading to a wavier oscillation and increased production of high-pressure ridges off the California coast which keeps needed rain offshore and contributes to the frequency and duration of hot and dry conditions.
As usually is the case, it’s impossible to attribute all the extreme weather patterns feeding the lengthening and intensifying California fire season, let alone these specific events occurring now. Nevertheless, strong and accumulating scientific evidence exists to say with high confidence that climate factors are unmistakably worsening the risk of wildfires throughout the state, and ensuring that when wildfires do happen, they will occur in an increasingly favorable environment for those fires to rapidly spread across large areas of dry vegetation.
The Urban Interface and Social Vulnerabilities
While it is doubtless true that forest management could stand to be improved, there is little evidence in the current circumstances that deteriorating conditions on forested land, most of which is managed by the federal government, played a central role in spawning the size, speed and impact of the current fires. As the Pasadena Fire Association recently noted on Twitter, the current fires were all spawned at what’s called the “urban interface” where the edges of settlements have pushed deeper into land which previously might have been forested or densely vegetated.
Out on the fringes of the urban interface, the meeting between human civilization, including the spreading electrical power lines and substations of SoCal Edison which appear to have been the proximate spark in the case of the catastrophic Woolsey Fire, is far more unsettled and dynamic than either in core urban or deeply forested areas. According to the National Institute of Standards and Technology this “wildland-urban interface” is growing nationally at a rate of 4000 acres per day and now constitutes the country’s single greatest wildfire risk.
Part of the pressure to continuously expand the wildland-urban interface, in California in particular, comes from economic development priorities and shortages of affordable housing in more prosperous urban areas. As housing prices continue to skyrocket in places like the Bay Area, for instance, more people search for housing alternatives in areas further and further from the urban core. Eventually, they arrive in reasonably high numbers in areas like Paradise in Butte County, CA which was entirely consumed by the Camp Fire this month.
Complicating matters along this wildland-urban periphery is the increasing confluence of areas of high wildfire risk with areas of high social vulnerability. For instance, a 2016 study published in the International Journal of Wildland Fire found that, while regions in the southeastern US in the wildland-urban interface zone were not necessarily more socially vulnerable in general than other areas, at least 10% of the total housing stock in these areas was both occupied by the most socially vulnerable households and in the areas of highest wildfire risk. People with the highest levels of social vulnerability are those who are least able to evacuate from fires, are most likely to suffer long-term adverse economic impacts, and to be afflicted with one or more chronic illness which might well be exacerbated either by the fires themselves or by the effects of long-term displacement due to the fires.
Notably, where social vulnerability appears to meet most significantly with wildfire risk is in areas with disproportionate shares of racial and ethnic minority populations. A recent study published in The Conversation found that “communities that are majority Black, Hispanic or Native American are over 50 percent more vulnerable to wildfire compared to other communities. Native Americans, in particular, are six times more likely than other groups to live in the most vulnerable communities.” These communities also displayed the lowest capacities for adaptation to changing wildfire landscapes.
Toward a Fire-Resilient Future
While there is no single solution to improving social resilience in the face of the growing threat of wildfires, a few key themes can be persistently found. For example, a 2016 study in the journal BioScience, “The Science of Firescapes: Achieving Fire-Resilient Communities,” argues that wildfire resilience requires a potent mix of wildland management to control burn zones, public education to integrate risk and hazard modeling into broad social awareness and policy systems, and improving community building design to mitigate fire hazards and expand long-term planning incentives which incorporate resilience thinking. Obviously, reducing the threat from escalating levels of carbon in the atmosphere, along with the myriad secondary effects from climate change would also be helpful.
Changing how we produce electrical energy in these interface areas can also boost resilience in significant ways. Localized power generation through renewable sources like solar and wind not only positively impacts the production of carbon pollutants driving global warming but also minimizes the need to extend higher risk grid-based systems into areas of high wildfire risk.
Beyond these sorts of long-term planning and risk mitigation issues, we can continue to improve access to primary medical services which can cut the specific health risks to populations posed by wildfire activity, including acute asthma. Community health centers, free clinics and other institutions in the medical safety sphere can play an invaluable role in promoting this kind of health resilience, which in turn feeds into the improved likelihood of meeting the health needs of the most vulnerable during wildfire events. Direct Relief continues in this sense to support robust community health both for its own sake and as a way to strengthen the emergency systems that socially vulnerable populations will rely on in a future where wildfires on the scale of the Camp Fire and Woolsey Fire seem to be increasingly likely.