In the United States, data collected by the National Inter-Agency Fire Center indicates that wildfires in recent years have caused far more damage than they did even a few decades ago. The average number of burned acres over the 2020-24 period was 7.3 million acres, a nearly 250 percent increase over the five-year period of 1983-88. Extensive research has found that the bulk of the increase in wildfires both in the United States and globally is occurring as a result of man-made climate change, as both higher temperatures and reduced rainfall have extended fire seasons, left trees and other vegetation drier and more prone to burning, and are far too often accompanied by high winds, which was a significant driving force in the extensive wildfires that hit greater Los Angeles, CA in January 2025. A 2023 study published in the Proceedings of the National Academy of Sciences (PNAS) found that the 500 percent increase in burn area for summer forest fires occurring in California for the fifteen year period ending in 2021 compared to a fifteen year period between 1971 and 1996 was almost entirely attributable to climate change. Similarly, a study released at the recent COP30 international climate change meetings in Brazil projected that climate change would induce significant increases in seasonal fire weather conditions across between 68 and 91 percent of the world’s fire-prone area by the end of the twenty-first century, depending on the emission scenario.
Recent research indicates that the increase in wildfire frequency and magnitude has had measurable impacts on human health, stemming in particular from respiratory issues. Evidence shows that wildfires generally emit a significant amount of fine particulate matter (PM2.5) that is inhaled by firefighters and people living in or near the areas where the fires have occurred. This fire-generated PM has been found to have a different composition than the fine PM that people encounter from urban air pollution, including more oxidative components (such as oxygenated hydrocarbons) and pro-inflammatory components (like aldehydes). They also emit more carbon monoxide and ozone, which are also harmful to human health.
An article published in Nature Communications Earth and Environment in 2025 found that the climate-change induced increase in wildfires has led to more than 15,000 additional deaths from wildfire-generated PM respiratory issues over a 15-year period (between 2006 and 2020) in the western United States alone. These human health impacts created an estimated economic burden of $160 billion for the same region. Intense wildfires that strike urban environs, like last year’s massive fires in the Los Angeles, CA area, also leave behind on the ground or in damaged structures a toxic brew of ash and residue that includes incinerated cars, electronics, paints, furniture and every other kind of personal belonging, which may contain an unknown quantity of pesticides, asbestos, plastics, lead or other heavy metals. This material can persist for months or even years unless properly remediated. Excessive exposure to these substances can lead to not only respiratory problems but also neurological and cardiovascular problems. Within weeks after the LA fire, a massive study of its human health impacts was commissioned with funding from the Spiegel Family Fund, bringing in researchers from California universities such as UCLA and UC-Davis, as well as Harvard University and the University of Texas at Austin.
The agricultural sector has also experienced significant problems as a result of the increased magnitude and frequency of wildfires in its proximity. As just discussed, respiratory issues often increase in populations close enough to wildfires to inhale smoke and particulate matter thrown off by the blaze. This is a particular problem for farmers, their family members, and farm workers in the western U.S., who are often harvesting crops at the same time that the region’s fire season is peaking. A survey of farm workers in Sonoma County in California found that nearly three-quarters of them had worked at least once under wildfire smoke or hazardous air quality conditions in the past several years. Even though the state of California requires farms to provide protective gear to their workers in such situations, most of them received inadequate protection, such as surgical masks, or nothing at all. This work was conducted by faculty members at the University of California at Berkeley.
In addition, it is likely that everyone living in close proximity to where wildfires occur suffers at least some mental stress due to awareness of risk of loss of life and property for themselves and their loved ones. It is reported that 31 people lost their lives in last year’s LA fires, and many thousands of families from neighborhoods like Pacific Palisades and Altadena have not yet been able to resume their normal lives yet,
When it comes to crop production, wildfires can not only destroy or damage the crops that are currently in the field, even those under irrigation, but it can also scorch the topsoil and subsoil layers in the field, potentially causing longer-term impacts. A meta-analysis conducted by scientists at Clemson University found that the composition of a microbiome can change after a wildfire, with a decline in the diversity of both fungal and bacterial species that are present. This can disrupt the functioning of the entire ecosystem. In addition, we know that certain crops, like grapes and cannabis, can be adversely affected by exposure to wildfire smoke, which can alter the quality of the crop. For example, most of the wine grape crop in Napa County, California in 2020 was affected by smoke taint in the wake of the major fires in northern California in that year, and the harvested grapes could not be used at all to make wine. Grape producers in that county collected $111 million in federal crop insurance indemnities for the 2020 crop year, as compared to an average of $3.7 million annually over the five previous years.
