Underestimated climate threat: Black carbon as a super pollutant

REDUCING greenhouse gas (GHG) emissions and limiting global temperature increase to 1.5°C or at least well below 2°C above pre-industrial levels is at the heart of the Paris Agreement. However, while carbon dioxide (CO2) is the major cause of global warming and has been a centrepiece of global discussions, there is a group of so-called super pollutants that are often overlooked when it comes to climate action. Not only are these super pollutants responsible for around 45% of global warming to date, but they also present a serious health hazard and are estimated to cause millions of premature deaths every year. Due to their short-lived nature, addressing super pollutants presents an opportunity for rapid impact while also yielding strong co-benefits for public health and clean air.

- By Dennis Mombauer

Unpacking super pollutants

The term “super pollutants” commonly refers to a group of greenhouse gases and aerosols that include methane, black carbon, fluorinated gases, nitrous oxide, and tropospheric ozone. These super pollutants are present in the atmosphere at lower concentrations than CO2 but have a much more powerful warming impact per ton and remain in the atmosphere for a much shorter time. This means that not only do they make an out-sized contribution to climate change, reducing them can also make a big and rapid difference.

Greenhouse gases under the Paris Agreement include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF6), and nitrogen trifluoride (NF3), with most of the attention placed on CO2 emissions. Reducing C02 emissions is vital to mitigate climate change and avoid catastrophic long-term impacts, especially given the long atmospheric lifetime of these emissions. However, the long-lasting nature of CO2 also means that any efforts towards climate action will take decades to show a significant impact.