A new research has revealed that plants absorb more carbon dioxide (CO2) under polluted skies than in a cleaner atmosphere.
The research team included scientists from the Centre for Ecology and Hydrology, the Met Office Hadley Centre, ETH Zurich and the University of Exeter.
According to lead author Dr Lina Mercado, from the Centre for Ecology and Hydrology, "Surprisingly, the effects of atmospheric pollution seem to have enhanced global plant productivity by as much as a quarter from 1960 to 1999."
"This resulted in a net 10 percent increase in the amount of carbon stored by the land once other effects were taken into account," Mercado added.
An increase in microscopic particles released into the atmosphere (known as aerosols), by human activities and changes in cloud cover, caused a decline in the amount of sunlight reaching the Earth's surface from the 1950s up to the 1980s (a phenomenon known as 'global dimming').
Although reductions in sunlight reduce photosynthesis, clouds and atmospheric particles scatter light so that the surface receives light from multiple directions (diffuse radiation) rather than coming straight from the sun.
Plants are then able to convert more of the available sunlight into growth because fewer leaves are in the shade.
Scientists have known for a long time that aerosols cool climate by reflecting sunlight and making clouds brighter, but the new study is the first to use a global model to estimate the net effects on plant carbon uptake resulting from this type of atmospheric pollution.
According to co-author Dr Stephen Sitch from the Met Office Hadley Centre, (now at the University of Leeds), "Although many people believe that well-watered plants grow best on a bright sunny day, the reverse is true. Plants often thrive in hazy conditions such as those that exist during periods of increased atmospheric pollution."
The results of the study have important implications for efforts to combat future climate change, which are likely to take place alongside attempts to lower air pollution levels.