1. The elements of fire

Fire is an exothermic chemical reaction that produces energy in the form of heat and light. ‘The elements of fire’ explains its composition through a ‘triangle’ of heat, fuel, and oxygen, and the processes of ignition and combustion. Large, accidental urban catastrophes like the Great Fire of London have led to redesigns and safety measures, but most wildfires start in the fuels on the ground surface and there is no ‘one size fits all’ model for suppressing wildfires such as the recent outbreaks in Portugal, Australia, and America. As the population encroaches into formerly wild areas, fire at the Wildland–Urban (or Wildland–Rural) Interface is an increasing problem.

4. Containing and suppressing fire

‘Containing and suppressing fire’ compares urban and pastoral understandings of fire. Prevention and suppression measures for one country may not be relevant in another, and even in the case of wildfires, one region may contain many different biomes, so formulating fire suppression policies can be complex. Some low-intensity surface fires may help prevent more dangerous crown fires; an urban understanding of all landscape fires as negative is not always helpful. With the increased popularity of living among flammable vegetation, the speed of wildfires can take some people by surprise. In urban fires, smoke has long been recognized as dangerous, but smoke from wildfires and peat burning can also cause health problems.

3. Fire and humankind

It is often impossible to determine from charcoal records whether fires had environmental or human causes; historically, it is also difficult to identify whether human-started fires were intended as methods of attack or started as controlled fires that then became uncontrolled. ‘Fire and humankind’ examines the relationship humans have with fire, starting with the discoveries that fire could be used for cooking, weapon-making, and socializing. While ‘slash and burn’ agriculture is often frowned upon, fire can be used in regular crop rotation, and often is. Fire has been used as a weapon of war, from the destruction of cities and ‘scorched earth’ approach to chemical weapons in the twentieth century.

6. Fire and climate change

Are rising global temperatures affecting the frequency and size of wildfires? ‘Fire and climate change’ distinguishes between wildfires that might be expected and those that may have been affected by a warmer climate’s impact on vegetation and weather patterns. ‘Plant invasives’—plants that have been introduced from other regions—have had a chaotic effect, exacerbating fires that would otherwise not have spread. There are various options available, including the experimental approach, the modelling approach, and the pragmatic approach, to predict and pre-empt outbreaks of fire. Improving the understanding of fire is a priority among both policy makers and the wider public throughout the world.

5. New technologies and changing fire policies

Fire is a natural part of some ecosystems, but not others. ‘New technologies and changing fire policies’ explores our comparatively recent use of satellite monitoring to transcend the limitations of observing fire on the ground. A surface fire can drastically alter the structure of soil and affect how it responds to rainfall, meaning that heavy rainfall after fires can lead to massive destruction through flowing sediment far away from the burn site. Fire suppression and prevention legislation is important, as is the development of ‘fire-wise’ or ‘fire-smart’ communities. Suppression is prioritized in urban areas, but tragedies such as the Grenfell Tower fire show that progress has still to be made.

2. The deep history of fire

‘The deep history of fire’ looks at how fire data can be preserved in nature, such as charcoal deposits and scars on the rings of trees. The history of fire is linked to changes in vegetation and the atmosphere over millennia, like the increasing size of plants and the atmosphere’s changing oxygen content. Wildfires are currently affected by climate in the form of temperature, rainfall, topography, and the length of dry and wet periods. As human intervention increases and the distinction between natural and human-started fires becomes blurred, an understanding of pyrogeography (the study of past, present, and projected wildfire) and pyrodiversity (its varying effects on biodiversity) is increasingly important.