Why Wildfires Keep Getting Worse

Every year seems to bring a new "worst fire season on record" headline. It's tempting to write that off as media exaggeration — but the underlying data doesn't support that read. Wildfires across the western United States really are burning more land, moving faster, and lasting longer into the calendar year than they did a generation ago. This isn't a feeling. It's measurable, and scientists have gone to considerable lengths to figure out exactly why.

Here's what the actual research shows — and why the trend isn't expected to reverse anytime soon.

The most cited piece of research on this topic is a 2016 study published in the Proceedings of the National Academy of Sciences by climate scientists John Abatzoglou and A. Park Williams. Using climate models and decades of fire records, they isolated the specific contribution of human-caused climate change to western U.S. forest fire activity — separating it from natural climate variability.

Their conclusion: human-caused climate change accounted for roughly half of the observed increase in "fuel aridity" (essentially, how dry vegetation is) since the 1970s, and nearly doubled the cumulative area burned by forest fires between 1984 and 2015. In absolute terms, that's an additional 4.2 million hectares burned — an area roughly the combined size of Massachusetts and Connecticut — that likely wouldn't have burned without the extra warming humans have added to the system.

Follow-up research has only reinforced this. A NOAA-supported study examining vapor pressure deficit (a measure of how much moisture the atmosphere is pulling from vegetation) across the western U.S. from 1979–2020 found that most of the increase is explained by human-caused warming — and that the region has passed a "critical threshold" since around the year 2000, after which climate change became the dominant driver of wildfire risk, rather than just a contributing factor. More recent analysis attributing emissions to specific fossil fuel producers estimated that nearly 40% of the forest area burned in western North America between 1986 and 2021 can be traced to heat-trapping emissions from a relatively small number of major fossil fuel and cement companies.

The science behind why this happens is fairly intuitive once it's laid out:

• Warmer air holds more moisture-pulling capacity — it draws water out of soil, vegetation, and dead fuel faster, leaving forests and brushland drier for longer stretches of the year
• Drier fuel ignites more easily and burns more intensely — a small spark that might have smoldered out in moister vegetation instead catches and spreads
• Fire seasons are stretching in both directions — conditions conducive to fire now start earlier in the spring and persist later into fall and winter than they used to, which is a large part of why California officials now describe wildfire season as functionally year-round rather than a defined summer-to-fall window
• The compounding effect gets steeper as warming continues — modeling in some forest types has found that even a relatively modest additional 1°C (about 2°F) of warming could increase the median area burned per year by several hundred percent, though the exact magnitude varies significantly by forest type and region

None of this means every individual fire is "caused by climate change" in a simple, direct sense — ignition still requires a spark, whether from lightning, downed power lines, equipment, or human activity. What the research shows is that climate change has fundamentally shifted the conditions fires burn under, making the fires that do start bigger, faster, and harder to contain than they would have been a few decades ago.

Climate is the dominant driver, but it isn't acting in isolation. A handful of other trends are stacking on top of it, and each one makes the underlying problem worse:

A century of fire suppression left forests overloaded with fuel. For most of the 20th century, U.S. forest policy was built around extinguishing every fire immediately. Many western ecosystems evolved to burn periodically at low intensity — suppressing that natural cycle for decades allowed dense underbrush and dead wood to accumulate far beyond historical norms, so when a fire does start, there's dramatically more fuel available to burn.

Widespread tree die-off from drought and bark beetles. Prolonged drought stresses trees and makes them far more vulnerable to bark beetle infestation — and beetle populations themselves have expanded their range as winters grow milder, since cold snaps that once controlled beetle populations happen less often. The scale has been enormous: an estimated 150 million trees died in California's Sierra Nevada alone between 2012 and 2019 during one severe drought and beetle outbreak. The relationship between beetle-killed trees and fire behavior is genuinely more complex than "dead trees equal worse fires" — researchers have found it depends heavily on how long ago the trees died and the specific forest type — but the dead and downed material left behind unquestionably adds to the total fuel load over time.

Invasive grasses are creating new fire pathways. Species like cheatgrass have spread aggressively across disturbed, drought-stressed land in the western U.S. These invasive grasses form continuous mats of fine, fast-drying fuel that can carry fire across a landscape at extreme speed — and problematically, they often recover and re-establish faster after a fire than native vegetation does, creating a cycle where invaded land burns more frequently over time.

More homes are being built where the fire is. The wildland-urban interface — the zone where development meets wildland vegetation — is one of the fastest-growing land use categories in the country, driven by population migration toward scenic, forested, and rural landscapes. This doesn't change how much land burns, but it directly changes how much of what burns is somebody's home. More of the built environment now sits inside fire-prone landscapes than at any point in the past.

Put together: the fuel is drier (climate), there's more of it (suppression legacy and tree die-off), it spreads faster (invasive grasses), and more homes are sitting directly in its path (WUI growth). These aren't four separate problems — they're compounding on top of each other in the exact same landscapes, at the exact same time.

Fire departments, municipal water systems, and mutual-aid response networks were largely built and staffed around a baseline level of fire activity — a baseline that assumed a shorter fire season and fires of a certain size and frequency. That baseline no longer describes reality. California, for example, now experiences dozens more days per year with fire-conducive conditions than it did fifty years ago — by one widely cited estimate, roughly 78 additional "fire days" annually compared to five decades ago.

More fire days spread across a longer calendar year means more simultaneous incidents competing for the same finite pool of engines, aircraft, and personnel — precisely the dynamic that stretched resources thin during the Palisades Fire and other major recent incidents. Water infrastructure faces the same scaling problem: systems engineered for a handful of structures needing hydrant flow at once simply weren't designed for the demand of an entire neighborhood burning simultaneously.

This is the uncomfortable bottom line: while the science says wildfire conditions will likely keep intensifying for the foreseeable future, the infrastructure built to respond to fire is not scaling at anywhere close to the same rate.

None of the research suggests this trend reverses on its own in the near term. Even under optimistic emissions scenarios, the warming already built into the climate system means fire-conducive conditions are expected to continue intensifying for years to come. The compounding factors — suppression-driven fuel loads, drought-stressed forests, invasive fuel sources, and continued WUI development — aren't going away either.

That combination means the responsibility for protecting any individual home is shifting, whether by design or default, further onto the property owner. Public firefighting resources will keep doing everything they can — but the data is clear that they're being asked to cover more ground, more often, with infrastructure that was sized for a fire era that no longer exists.

Understanding this trend isn't about fear — it's about making an accurate risk assessment instead of an outdated one. If the frequency and intensity of wildfire threat to your property is genuinely higher than it was ten years ago, and public response capacity hasn't grown at the same pace, the case for having an independent, on-property line of defense gets stronger every year, not weaker.

13 HP Honda GX390 Twin-Stage Fire Pump Package

An independent, grid-independent line of defense — turn your pool, tank, or pond into real reach and pressure before a fire arrives.

$2,900.00View Details →

Barricade II Fire Blocking Gel — Complete Kit

U.S. Forest Service–approved gel that extends your water's effectiveness and creates a protective barrier that holds up far longer than plain water.

$1,073.18View Details →

Sources & further reading: Abatzoglou & Williams, "Impact of anthropogenic climate change on wildfire across western US forests," PNAS (2016); NOAA's Wildfire & Climate Connection research summary; Union of Concerned Scientists emissions-attribution wildfire research; USDA Forest Service and Colorado State Forest Service research on bark beetle-fire interactions; CalMatters reporting on California's expanding fire season.

Keep Reading

Preparedness

Are You Ready for Wildfire?

A 6-step home defense checklist — defensible space, ember hardening, independent water supply, and fire retardant gel.

Strategy

What the Palisades Fire Taught Us

Our infrastructure was never built for urban conflagrations — when the hydrants ran dry, homeowners were left to fend for themselves.

Cost & Insurance

The Real Cost of Rebuilding After a Wildfire

Most homeowners are underinsured for wildfire rebuild costs — $450–$800/sq ft in California fire zones. Why preventing the loss is the better investment.