It saturates the atmosphere of many Asian countries, invades the oceans and melts the glaciers of the Himalayas and the Arctic sea ice. “Black carbon” is a little-known but omnipresent super-pollutant.
A threat to public health. While it contaminates the air, the oceans and accelerates the melting of glaciers, “black carbon” is not new. Indeed, according to Xavier Mari, biogeochemist at the Research Institute for Development (IRD), “the first human who domesticated fire already breathed black carbon”.
Formed during the incomplete combustion of biomass and fossil fuels, this pollutant has been omnipresent for millennia. Coming from domestic heating and cooking – which represents 43% of global emissions –, transport and industry, soot carbon particles are particularly dangerous and penetrate deep into the lungs. “These fine particles in general are linked to certain cancers and heart diseases,” Bertrand Bessagnet, air quality manager at the International Center for Integrated Mountain Development (ICIMOD) in Kathmandu (Nepal) and author of a thesis on carbonaceous aerosols.
Inserm researchers showed that this pollutant was associated with a 30% increase in the risk of lung cancer, in a study published in 2021.
Accelerated global warming
Although its lifespan in the atmosphere does not exceed twelve days, its warming power is colossal: 1,500 times greater than that of CO2. Its effect results from its black color, which absorbs light and stores heat.
Carried by the winds, the “black carbon” is deposited on glaciers and ice floes, accelerating their melting. In the French Alps, it reduces the duration of snow cover by 17 days on average over 40 years, threatening mountain ecosystems. “It only takes small quantities to change the color of the snow and accelerate the melting,” explained Marie Dumont, CNRS specialist.
A global ecological and health challenge
Present in the atmosphere, oceans and even the human placenta, “black carbon” contaminates the entire planet. Every year it enters the food chain, from microorganisms to marine mammals. They are found everywhere, even in newborns.
There is, however, hope for regulation. Black carbon emissions have declined in Europe since the 2000s, thanks to stricter regulations. But the battle is far from won. The Clean Arctic Alliance calls for binding measures to reduce emissions from ships, which are particularly harmful to the Arctic.
