Multi core wildfire soot particles found to boost global warming impact

by Riko Seibo
Tokyo, Japan (SPX) Jan 01, 2026
Traditionally, climate models have represented black carbon particles as having a single carbon core surrounded by a shell, but new work on wildfire smoke shows that about 21 percent of particles, especially those larger than 400 nanometers, actually contain two or more cores.

An international team including researchers from the Chinese Mainland, Hong Kong, the United States, the United Kingdom, Israel, Japan, and South Korea used field observations from Yunnan's wildfire season and advanced electron microscopy to document these multi core black carbon aerosols and their larger core diameters above 200 nanometers.

The study indicates that these multi core particles, which had not been represented in global climate models, likely explain why measured black carbon light absorption has been underestimated by roughly 50 percent compared with model estimates.

Lead author Dr Chen Xiyao said, "The mixing state of BC is fundamental to understanding its climate effects. Ignoring coagulation and multi-core structures impedes accurate assessment and policy development regarding BC's role in climate change."

To quantify these effects, the team built a machine learning emulator for absorption enhancement and integrated it into a global atmospheric model to test how multi core particles change black carbon's radiative impact.

Their simulations show that multi core black carbon particles increase the global average absorption of black carbon by about 19 percent, with particularly strong effects in wildfire influenced regions such as Southeast Asia, southwestern China, the Tibetan Plateau, Southern Africa, and North America.

Corresponding author Professor Li Weijun explained, "Our nanoscale observations have identified abundant multi-core black carbon particles in both wildfire and urban environments-structures previously unrepresented in climate models. By refining our algorithms, we have simulated their enhanced optical absorption and quantified their contribution to global warming, enabling more precise evaluation of black carbon's climate impact. This study provides a more solid foundation in atmospheric science for climate governance and global cooperation."

EdUHK atmospheric scientist Dr Joseph Ching, who led key aspects of the modeling work, said the combination of particle scale measurements, optical simulations, global climate modeling, and machine learning improves understanding of black carbon's warming influence and helps constrain its radiative forcing for use in climate policy.

The authors argue that climate models should explicitly include the multi core mixing state of black carbon so that global radiative forcing assessments and emission reduction strategies better capture the real contribution of wildfire and urban soot.

Co author Professor Mark Jacobson of Stanford University emphasized that the findings strengthen the case for black carbon as the second largest driver of global warming after carbon dioxide, underscoring the need for rapid mitigation.

With wildfire activity and human driven emissions expected to rise under continued warming, the researchers contend that integrating multi core black carbon behavior into climate modeling is important for effective climate governance, international collaboration, and progress on the United Nations Sustainable Development Goals related to health, sustainable cities, and climate action.

Research Report:Locating the missing absorption enhancement due to multi-core black carbon aerosols