Atmospheric black carbon in the climate system
Review article, 2026
Black carbon (BC) aerosols are short-lived climate pollutants with important, but uncertain, climate impacts. In this Review, we synthesize observations of atmospheric BC concentrations, sources, optical properties, lifetimes and climate effects, drawing comparisons with atmospheric model simulations. Isotopic fingerprinting reveals regional differences in BC sources, with biomass burning contributing 93 ± 3% in sub-Saharan Africa, 56 ± 7% in South Asia and 28 ± 5% in East Asia. Atmospheric BC loadings have declined in South America, East Asia, Europe and North America, and stabilized in Africa and South Asia owing to clean air policies and advances in technology and practices. The optical properties of BC influence its climate effects. The global-mean mass absorption coefficient (MAC550 ) of atmospheric BC is 12.3 ± 5.8 m2 g−1, being highest in Africa, Europe and South Asia. MAC550 is enhanced near universally by 1.6 ± 0.4 owing to ageing during long-range transport. In major emission regions, the aerosol absorption optical depth and the direct aerosol radiative forcing ratio between the bottom and the top of the atmosphere are lower in model simulations than in observations by factors of 2 and 1.5, respectively. Relative to long-term observations, model simulations estimate higher BC deposition fluxes but lower concentrations and sunlight absorption. These discrepancies have implications for the accuracy of model representations of humidity, clouds, precipitation and climate forcing. Future research should prioritize comparisons of emission inventory and model estimates with observations to enhance model accuracy and guide mitigation efforts.
Author
Örjan Gustafsson
Stockholm University
Krishnakant Budhavant
Maldives Climate Observatory
Indian Institute of Science
Navinya Chimurkar
Indian Institute of Technology
Sean Clarke
Stockholm University
Gabrielle Dreyfus
Institute for Governance and Sustainable Development, Inc.
Xin Gong
Nankai University
Z. Klimont
International Institute for Applied Systems Analysis
Klaus Klingmüller
Max Planck Society
Sang Woo Kim
Seoul National University
Jos Lelieveld
Max Planck Society
Cyprus Institute
Gunnar Myhre
Cicero Senter for klimaforskning
Hari Ram Chandrika Rajendran Nair
Chalmers, Space, Earth and Environment, Geoscience and Remote Sensing
Jianfei Peng
Nankai University
V. Ramanathan
University of California
Cornell University
Archita Rana
Jülich Research Centre
M. R. Manoj
Stockholm University
S. K. Satheesh
Indian Institute of Science
Chandra Venkataraman
Indian Institute of Technology
Qiang Zhang
Tsinghua University
Nature Reviews Earth and Environment
2662138X (eISSN)
Vol. 7 5 312-328Subject Categories (SSIF 2025)
Climate Science
Meteorology and Atmospheric Sciences
DOI
10.1038/s43017-026-00773-3