- The number of “fire weather” days in the United States exceeds conventional hotspots.
- Climate change is regarded as the main driver of fire proneness.
- The numbers in states such as Oklahoma and Kansas have increased.
Researchers said on Wednesday that climate change is fueling conditions for faster-growing wildfires in the western United States-including in some places, from Oklahoma to Nebraska, which may be unexpected.
Wildfires have caused devastating damage to large areas of the West Coast, but fire-prone days in other western states have also peaked, indicating that safe havens away from deadly fires will continue to decrease without stepping up efforts to curb climate change.
“(In) most of these communities, it’s not a question of whether it will happen – it’s a question of time,” said Caitlin Weber, a data analyst at the Climate Center of the research group that released the report.
Weber grew up near more than 100,000 acres of land outside Sacramento that were destroyed by the Caldo Fire this month. He said that, as expected, parts of California are the most fire-prone areas.
She said that what is even more surprising is that high temperatures, winds and low humidity are increasing the risk of fires in other states for more and more days.
“Into parts of Oklahoma and Kansas… even parts of Nebraska-things are changing,” she said.
Weather more frequently laid the groundwork for these serious fires.
According to the analysis of the federal climate zones of 17 states, the San Joaquin and Sacramento basin areas in California ranked second and seventh in percentage increase in the number of days of “fire weather” between 1973 and 2020, respectively.
A fire-prone day is considered a day where the temperature reaches at least 7-11°C, depending on the season, with wind speeds up to 15 miles per hour and relative humidity close to the threshold used by the federal government to define increased fire risk-many places The humidity is 15% in parts of the west.
Weber said: “Climate change has led to higher temperatures, and higher temperatures have led to a severe drought trend in the western region. This has greatly increased the risk of more severe wildfires.”
According to data from the Congressional Research Service, California accounts for nearly 40% of the total area burned by wildfires in the United States in 2020. But the fire risk in other states is also on the rise.
Two regions in Nevada, including Las Vegas and the central and southern parts of the state, had the highest average number of “fire weather” days per year between 1973 and 2020, at 94 and 93 days, respectively.
According to data from the National Interagency Fire Center, in 2020, wildfires in Nevada burned more than 250,000 acres, ranking among the best of all states in the United States.
The analysis found that the number of fire days in New Mexico, California, and Texas has increased the most since 1973. Compared with 1973, the current “fire weather” has increased by about two months.
The report found that, at the same time, parts of southern Texas, California, Oregon, and Washington have experienced the largest percentage increase in the number of fire weather days since the early 1970s, with the number of such days more than doubling.
Fires in southwest Oklahoma, which borders Texas, increased by 169%.
Going east?
Climate scientist Michael Weiner said that this increase in fire risk is not limited to the western United States. Countries such as Greece, Turkey, Spain and France are now experiencing successive destructive fire seasons.
Weiner, one of the lead authors of the Intergovernmental Panel on Climate Change’s August report, said that US states further east may also find themselves at increasing risk.
For example, the Greenwood fire in northern Minnesota has scorched nearly 20,000 acres in the past 10 days.
“I expect the fire risk will increase throughout the mid-latitudes,” Weiner said. “Dry climates are always more prone to such incidents, but forest fires may occur in the eastern United States.”
Weber of the Climate Center said that as climate change has led to higher temperatures in many states, fires have become a risk in more places.
She said the report is “a warning sign that we really need to pay attention to this.”
Weber warned that weather is only one factor in the risk of wildfires. It also depends on bushes and other combustible fuels and the topography of an area.
She said the Bootleg fire, which burned more than 400,000 acres in Oregon since last month, occurred in the south-central part of the state, which is outside the highest risk area reported.
Weiner, a senior scientist at Lawrence Berkeley National Laboratory in California, said it is clear that higher temperatures and drier soils are fueling fires.
“Because the weather is hotter, no matter how the humidity changes, the soil is drier and the plants are drier. Therefore, it is more flammable,” Wehner said.
The Climate Center analysis found that since 1973, the frequency of fires in certain areas of North Dakota and South Dakota, and parts of Kansas and Nebraska has declined due to relatively low temperatures in spring and summer.
However, studies have found that this cooling is expected to be temporary and may be affected by changes in land use and crop irrigation, as well as natural changes.
