Global trends in wildfire and its impacts: perceptions versus realities in a changing world

Abstract

Wildfire has been an important process affecting the Earth's surface and atmosphere for over 350 million years and human societies have coexisted with fire since their emergence. Yet many consider wildfire as an accelerating problem, with widely held perceptions both in the media and scientific papers of increasing fire occurrence, severity and resulting losses. However, important exceptions aside, the quantitative evidence available does not support these perceived overall trends. Instead, global area burned appears to have overall declined over past decades, and there is increasing evidence that there is less fire in the global landscape today than centuries ago. Regarding fire severity, limited data are available. For the western USA, they indicate little change overall, and also that area burned at high severity has overall declined compared to pre-European settlement. Direct fatalities from fire and economic losses also show no clear trends over the past three decades. Trends in indirect impacts, such as health problems from smoke or disruption to social functioning, remain insufficiently quantified to be examined. Global predictions for increased fire under a warming climate highlight the already urgent need for a more sustainable coexistence with fire. The data evaluation presented here aims to contribute to this by reducing misconceptions and facilitating a more informed understanding of the realities of global fire.This article is part of themed issue 'The interaction of fire and mankind'.

Keywords: area burned; climate change; costs; fire severity; media; risk.

Figure 1.

Public awareness campaigns supporting total exclusion of fire from our forests have driven largely our current perceptions of fire. For example, (a) Smokey Bear has been the American champion against fire since the 1950s; (b) the ‘all against fire’ campaign in Spain during the late 1980s and early 1990s also had wide national relevance.

Figure 2.

Wildfire occurrence (a) and corresponding area burnt (b) in the European Mediterranean region for the period 1980–2010. Source: San-Miguel-Ayanz et al. [37].

Figure 3.

Area burned, number of fires and suppression costs (inflation adjusted to 2016 equivalent) for the USA with linear trend lines (1991–2015). Data: National Interagency Fire Center [48].

Figure 4.

Global area burned with enlarged sections of the globe (1996–2012) and global population density with examples where regions with high proportions of area burned coincide with high population densities. (Based on and modified from Moritz et al. [19] and NASA (http://neo.sci.gsfc.nasa.gov/view.php?datasetId=SEDAC_POP).)