Data shows the worsening trend of California wildfires

Cumulative Acres Burned, 1979-2018, for all Fires in CaliforniaIt’s clear to most citizens of California that wildfires have become more intense over the last few years. Researchers at UC Santa Barbara and the Nature Conservancy have compiled a new dataset of damage caused by wildfires in California in areas protected by the state of California. (Some of the data does not include fires on lands protected by federal agencies, such as the U.S. Forest Service, National Park Service, and the BLM). The report illustrates how the recent set of severe fires fits into a broader trend of increasing burn area and damage over the past 40 years.

The report was written by: Hanna Buechi (Environmental Market Solutions Lab, UCSB), Dick Cameron (The Nature Conservancy), Sarah Heard (The Nature Conservancy), Andrew J. Plantinga (Environmental Market Solutions Lab, UCSB), and Paige Weber (Environmental Market Solutions Lab, UCSB).

The researchers studied data on fire perimeters and estimates of damages for each fire and used the information to calculate trends involving the number and timing of fires throughout the state by time of year. They also calculated the total area burned and specifically identified the amount of wildland urban-interface burned. These are areas where houses intermingle with wildland vegetation, and are of particular concern to those studying wildfire.

Andrew Plantinga
Andrew Plantinga. UCSB photo.

“The main finding is that the recent severe fires in California — including the Thomas fire in 2017 and the Camp fire in 2018 — are part of a trend in California over the past four decades,” said Andrew Plantinga, an economics professor at UC Santa Barbara’s Bren School of Environmental Science & Management. “The trend is toward more wildfires that burn larger areas and cause more damage.”

The number of acres burned per year has not only been increasing, the report found, it is also accelerating. And this increase isn’t only during the season’s peak, from June through October. The state is also seeing a longer fire season, with more acres burned in late fall than in the past. And while greater burn areas don’t automatically translate to greater damages, the researchers found that these, too, have been on the rise.

“I expected the recent severe fires to be outliers, and they are,” said Plantinga, “but it’s also clear that they represent part of a trend toward larger and more damaging fires.”

Cumulative WUI Acres Burned in California, 1979 – 2018

The report is part of a larger effort to estimate the costs associated with a business-as-usual approach to development in California, when considering the potential impacts of climate change. The team had previously found that interventions on natural and working lands — like forests, farms and rangelands — can contribute 2.5 times the emissions reductions by 2050 as residential and commercial sectors combined.

What’s more, for every dollar spent on implementing land-use strategies, close to fifty cents would be recouped in economic benefits. And that’s without accounting for other positive impacts, the previous report states.

California Civilian and Firefighter Deaths
Civilian and Firefighter Deaths on wildfires in California that occurred on State Responsibility Area lands, 1979 – 2017.
California Estimated Value of Structure Losses
Estimated Value of Structure Losses (in 2018 dollars) for State Responsibility Area Fires, by Year, 1979 – 2018.

Acres Burned by Month and Decade for all Fires in California

California Map of Structure Losses and Fire Perimeters
Map of Structure Losses and Fire Perimeters for State Responsibility Area Fires, 1979 – 2018.