Forest fires have a detrimental impact on human health.

Smoke from fires sends particulate matter into the atmosphere: tiny pieces of material that pollute the air and get into human lungs, causing respiratory and potentially cardiovascular problems. 

The smallest particles, known as PM2.5, are the most concerning; they can poison the air for hundreds of kilometres beyond the location of the fire. Inhaling these pollutants can cause respiratory issues in both the short and long term, ranging from coughing to asthma, pneumonia, chronic obstructive pulmonary disease (COPD) and lung cancer. As well as the elderly, the populations most likely to suffer health issues are children, pregnant women, people with pre-existing conditions, and firefighters.

Tropical peat fires are particularly harmful to human health. They are especially difficult to extinguish as they burn both horizontally and vertically, meaning the fire may also be underground. Peatlands in Indonesia are predominantly drained and burned for palm oil and pulp plantations. These blazes emit three to six times more particulate matter per unit of carbon burned than fires on grasslands and forests. This is particularly troublesome in Indonesia, which contains 36% of the world’s tropical forest peatlands, covering more than 20 million hectares. Large areas of this peatland have been drained and cleared of vegetation, which makes them susceptible to fire. During the 2019 fires in Indonesia, nearly one million people suffered from acute respiratory infections.

Medical model of lungs in semi-blurred lense focus.
Photo by Robin Weermijer, 2020

Medical staff washing hands.
Photo by Piron Guillaume, 2020.


The health impacts of fires are magnified by Covid-19.

Various health organisations, such as the WHO and the European Public Health Alliance, have warned that people living in polluted areas may be at greater risk from coronavirus. Analysis has shown that even a tiny increase in particle pollution levels in the years prior to the pandemic was associated with a 15% increase in the death rate. Forest fires could also aid the transmission of coronavirus by triggering large scale emergency evacuations, with people forced to live in overcrowded shelters, where social distancing is impossible. Some 80,000 people were evacuated during the California fires in 2016, for instance.

Fire season also threatens placing additional stress on an already overburdened health system, due to increased emergency visits and hospital admissions from patients with respiratory problems. In Brazil, intensive care units have already become saturated as coronavirus has spread through the country. In the state of Amazonas, the government reported that occupancy had reached 96% in April 2020. Both Brazil and Indonesia could face dire problems in their health systems if the pandemic is not under control as the fire season progresses. 

Climate Change

While climate change is making forest fires worse in many places, dry weather does not explain the recent spike in tropical forest fires in Brazil and Indonesia.

However, there are links between these fires and climate change. As soils and vegetation are burned, they release their stored greenhouse gases, contributing to carbon emissions. In 2019, fires in the Brazilian Amazon emitted 392 million metric tonnes of carbon dioxide, equivalent to more than 80% of the country’s emissions in the previous year. Indonesia’s fires emitted 360 million metric tons of carbon dioxide in summer 2019. Peat fires are especially damaging: whereas tree regrowth can balance emissions from some forest fires, when peat burns it releases carbon that has been stored over thousands of years and cannot be replaced. The black carbon emitted by Amazonian fires has also been linked to the melting of glaciers in the tropical Andes. Climate change also increases the frequency and intensity of El Niño years, which currently occur about once every five years. In these years when drought increases, fires ignited by humans deforesting can more easily become out of control due to the dry conditions.

The clearing of the forest in the 'Day of Fire' areas continues even after the attention that the fires attracted inside and outside Brazil.

Photo by Fernando Martinho/Repórter Brasil, 2019

Ibu Rosalina showing the Nankay Cemedak fruit in Kapuas Hulu,
Kalimantan, Indonesia. Photo by hoto by Icaro Cooke Vieira/CIFOR, 2017


Forest fires have economic consequences, and these could be particularly acute as the world faces a recession in the wake of Covid-19.

Fires have a range of economic consequences including costs to healthcare services, damaging tree plantations, crops and houses, delaying flights and transportation, and forcing school closures and evacuations. Even low-intensity fires can kill up to 50% of trees and reduce the value of forests for local people. The World Bank estimates that the economic loss caused by the 2019 fires in Indonesia amounted to US$5.2 billion, equivalent to 0.5% of the country’s GDP. It estimates that US$157 million of this was related to direct damage and US$5 billion was from affected economic activities. However, these costs do not encompass the whole scope of the damage, such as reduced quality of education due to ill health and falling demand for Indonesia’s palm oil as trade relations sour with European countries. In Brazil, a nascent area of research into the effects of deforestation on local climatic change suggests that soy and maize crop yields could be reduced, with potential economic consequences for farmers as well as global grain prices.