Microplastics can influence climate change, world-first study suggests

Airborne microplastics could have the potential to influence climate change, a new study claims.

The world-first study, published in Nature today, modelled the possible climate effects of airborne microplastics.

It found the tiny particles scatter and absorb light, which respectively has a cooling and heating effect on the climate.

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Lead author Laura Revell from the University of Canterbury told 9News the modelling so far indicates microplastics have an overall cooling effect.

"They scatter light and radiation like tiny disco balls, which has a cooling effect," Dr Revell said.

"(But) microplastics can also absorb light and in a small way can contribute to the greenhouse effect."

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However, Dr Revell is worried the heating effect could become dominant should concentrations of airborne microplastics increase in the atmosphere.

"It is possible the warming signal could become larger than the cooling signal," she said, explaining there is not enough data measuring factors like the position of microplastics in the atmosphere and colour of the particles, which affects absorption.

"There's just not a lot of data out there (but) either way we do expect it's going to get bigger in the future."

She said she's concerned about the fact many studies don't see microplastics smaller than 11 micrometres.

"It's possible there are all these tiny, tiny plastics out there and we just don't know about them yet."

Large concentrations of airborne microplastics have been found over two major cities: Beijing in China, and London in the United Kingdom.

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"Studies have been done in Beijing and London that identify them as being present in quite high concentrations," she said.

"In big cities, they may be present in the order of a couple thousand microplastics per cubic metre.

"It's possible microplastics in really populated regions could already be having local influence on climate, but I think the signal would be fairly small unless the abundance gets massive in future."

She added microplastics are not as prevalent as other types of atmospheric aerosols, such as dust.