Climate at a Glance: U.S. Wildfires

Burning pine forest in the Western United States. Image licensed from 123RF

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Key Takeaways:

  • Compared to the first half of the twentieth century, the number of wildfires occurring in the United States over the past decade is lower, and the fires have been less severe.
  • In years in which there has been an increase in wildfire activity during the past decade, the fires have usually involved substantially fewer acres of burnt land compared to much of the twentieth century.
  • Even in the worst wildfire seasons occurring recently, wildfires typically burned one-fifth to half as much land as standard wildfire seasons during the early twentieth century.
  • Drought is the key climate factor for wildfires, an important consideration because the United States has experienced relatively few droughts recently.
  • Data showing greater numbers of acres lost to wildfires in previous decades were removed from an important database by a government fire agency, likely because the data did not support the claim that wildfires are becoming more frequent.

Short Summary:

Wildfires, especially in arid parts of the United States, have always been a natural part of the environment, and they likely always will. Global warming did not create wildfires. In fact, wildfires have become less frequent and less severe in recent decades. One of the key contributing factors has been that the United States has experienced fewer droughts in recent decades than in periods throughout the twentieth century.1

The U.S. National Interagency Fire Center (NIFC) provides data about U.S. wildfires dating back to 1926. NIFC data show the number of acres burned in recent years has been far less than it was during the early twentieth century. (See Figure 1.) The number of acres burned in modern wildfires is roughly one-fourth to onefifth of the size of the record values that occurred in the 1930s. At that time, the peak wildfire burn was greater than 52 million acres. From 2010 to
2020, the peaks were typically just 10 million acres or less.2

Figure 1. Wildland Fires: Number of Acres Burned in the United States, 1926–2019

Figure 1. Available wildfire acreage burned, by year, in the United States, 1926 to 2019. This includes data from NIFC prior to the disappearance of data that occurred in 2021. Graph by Anthony Watts.

Some climate activists cite a relatively small upward trend, starting in 1983, in the number of acres burned by wildfires as evidence that climate change has been making wildfires considerably worse. However, the data show that trend is minor compared to the much longer historical record. Wildfires burned far more acres, on average, prior to 1950.

Even more disturbing, climate activists and several scientists have deleted significant amounts of wildfire data from years prior to the start of the upward trend, making it appear as though the United States is in the midst of a much greater trend than the historical record shows.


In March 2021, NIFC removed wildfire data from years prior to 1983. The stated justification for the decision was that data are allegedly “unreliable,” an assertion that should be viewed with great skepticism considering that this supposedly unreliable data had been used in peer-reviewed scientific publications for many decades.

By disappearing all data prior to 1983, which happens to be the lowest point in the dataset for the number of fires, NIFC data now suggest wildfires are getting much worse and that the number of fires is aligned with global temperature.3 Without a distorted dataset, these dire claims about wildfires would be impossible to make with any
degree of credibility. (See Figure 2.)

Figure 2. A Comparison of NIFC Datasets, Number of Acres Burned in the United States, 1926–2020 and 1983–2020

Figure 2. A comparison of NIFC wildfire datasets. It illustrates that when NIFC agreed to remove
wildfire data for the years prior to 1983, it provided the public with a distorted view of wildfires. Graphs
by Anthony Watts.

References:

  1. See Climate at a Glance, “Drought,” The Heartland Institute, accessed August 15, 2021,
    https://climateataglance.com/climate-at-a-glance-drought/
  2. National Interagency Fire Center, “Total Wildfire Acreage Burned by Year in the United
    States, 1983 to 2020,” data last accessed on August 16, 2021, https://www.nifc.gov/fireInfo/fireInfo_stats_totalFires.html
  3. WattsUpWithThat.com, “CAUGHT: ‘Inconvenient’ U.S. Wildfire Data Has Been ‘Disappeared’ by National Interagency Fire Center”, 5/13/2021, https://wattsupwiththat.com/2021/05/13/caught-inconvenient-u-s-wildfire-data-has-been-disappeared-by-national-interagency-fire-center-nifc_fire/

Climate At A Glance is a Project of The Heartland Institute

Email: think@heartland.org