Smoke from wildfires, linked to climate, grows daily more of a threat. Now science can see the direct human health cost.

LONDON, 14 September, 2021− Smoke from wildfires in burning forest vegetation now claims at least 33,500 lives a year worldwide. And that’s based on data from just 749 cities in 43 countries during the years 2000 to 2016.

The true cost to humankind of wildfire pollution from tiny particles of incinerated vegetation in cardiovascular and respiratory deaths will inevitably be much larger.

And a separate study finds that the fires now blazing every year in the Brazilian Amazon send more than 48,000 Brazilians to hospital. In the same timespan − the first 15 years of this century − an estimated 755,091 Brazilians have been admitted to hospitals with respiratory and cardiovascular conditions triggered by wildfire pollution.

Both findings are based on the use of subtle statistical techniques to tease out from public records the direct causes of hospitalisation and death. In the first study, researchers report in the journal Lancet Planetary Health that they combed through records of more than 66 million deaths from all causes in a selection of cities from 43 nations and regions, and then applied sophisticated mathematics to calculate which cases would have been triggered by the inhalation of what health scientists called “fine particulate matter” − fine enough to enter the lungs, cross the walls of the lung tissue and enter the blood circulation.

Wildfire smoke is deadlier than most forms of atmospheric pollution: it’s made up of smaller particles of a different chemical composition forged in higher temperatures. It can also travel further, up to 1,000 kms (625 miles), and still be potentially sickening.

Urban penalty

And, in a world in which planetary temperatures are soaring, droughts are becoming more intense and more frequent, and human destruction of the forests more devastating, the potential dangers are increasing.

California in 2020 recorded more than 46,000 outbreaks of wildfire. In the 2019-2020 burning season, Australia lost more than 100,000 sq kms of bush, forest and parkland to wildfire.

Brazil’s Amazon forest, disfigured by an accelerating number of fire outbreaks in the last two years, has lost more than 33,000 sq kms of canopy to fire every year since 2003.

A second study in the same journal identifies the cost across the decades to the nation with the largest and most important tropical forest on the planet: Brazil.

The fires may burn in distant regions now being converted to cattle ranches, soy plantations or mining operations, but the price is paid in crowded cities.

“In a world in which planetary temperatures are soaring and human destruction of the forests more devastating, the potential dangers are increasing”

Toxic smoke from these wildfires in the Amazon region can rise to enormous heights and travel colossal distances to trigger asthma, heart attack, stroke, respiratory conditions, hospitalisation and death, in young children and the elderly in particular.

The Lancet is one of the world’s oldest and most prestige-laden medical journals: it has also paid close attention to the health costs linked in any way to climate change driven by profligate greenhouse gas emissions, as the use of fossil fuels continues to expand.

It and its sister publications have examined the global hazard to new-born children in a fast-warming world; the massive global death toll of ever-increasing extremes of heat and cold; the health costs in terms of hunger and malnutrition that will follow as harvests wither, and as energy, protein and mineral levels in staple foods begin to change with ever-higher temperatures; and even to the direct consequences to the workforce and the economy as extreme temperatures begin to rise to unprecedented levels.

So the latest finding is in part a warning to governments, municipalities, nations and above all health professionals to be prepared for greater levels of hospitalisation and death.

Although one study is a worldwide look, the second a closer look at the costs to just one nation, the problem is truly worldwide: Japan, according to data from 47 cities, loses 7,000 people a year to wildfire pollution; Mexico (10 cities) more than 3,000; and the US records more than 3,200 deaths in 210 cities each year. − Climate News Network